Merge pull request #2551 from ehuss/bump-version

Update to 0.4.45
2025-12-28 13:51:10 -05:00 · 2025-02-17 18:26:17 +00:00 · 2025-02-17 10:18:04 -08:00 · 2025-02-17 18:12:15 +00:00 · 2025-02-17 17:52:50 +00:00 · 2025-02-17 09:41:52 -08:00
87 changed files with 4463 additions and 1617 deletions
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -3,47 +3,47 @@ on:
  release:
    types: [created]

+defaults:
+  run:
+    shell: bash
+
+permissions:
+  contents: write
+
 jobs:
  release:
-    name: Deploy Release
    runs-on: ${{ matrix.os }}
    strategy:
      matrix:
-        target:
-          - aarch64-unknown-linux-musl
-          - x86_64-unknown-linux-gnu
-          - x86_64-unknown-linux-musl
-          - x86_64-apple-darwin
-          - x86_64-pc-windows-msvc
        include:
          - target: aarch64-unknown-linux-musl
-            os: ubuntu-20.04
+            os: ubuntu-22.04
          - target: x86_64-unknown-linux-gnu
-            os: ubuntu-20.04
+            os: ubuntu-22.04
          - target: x86_64-unknown-linux-musl
-            os: ubuntu-20.04
+            os: ubuntu-22.04
          - target: x86_64-apple-darwin
            os: macos-latest
+          - target: aarch64-apple-darwin
+            os: macos-latest
          - target: x86_64-pc-windows-msvc
            os: windows-latest
+    name: Deploy ${{ matrix.target }}
    steps:
-    - uses: actions/checkout@master
-    - name: Install hub
-      run: ci/install-hub.sh ${{ matrix.os }}
-      shell: bash
+    - uses: actions/checkout@v4
    - name: Install Rust
      run: ci/install-rust.sh stable ${{ matrix.target }}
-      shell: bash
-    - name: Build and deploy artifacts
+    - name: Build asset
+      run: ci/make-release-asset.sh ${{ matrix.os }} ${{ matrix.target }}
+    - name: Update release with new asset
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-      run: ci/make-release.sh ${{ matrix.os }} ${{ matrix.target }}
-      shell: bash
+      run: gh release upload $MDBOOK_TAG $MDBOOK_ASSET
  pages:
    name: GitHub Pages
    runs-on: ubuntu-latest
    steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v4
    - name: Install Rust (rustup)
      run: rustup update stable --no-self-update && rustup default stable
    - name: Build book
@@ -56,3 +56,14 @@ jobs:
        curl -LsSf https://raw.githubusercontent.com/rust-lang/simpleinfra/master/setup-deploy-keys/src/deploy.rs | rustc - -o /tmp/deploy
        cd guide/book
        /tmp/deploy
+  publish:
+    name: Publish to crates.io
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Rust (rustup)
+        run: rustup update stable --no-self-update && rustup default stable
+      - name: Publish
+        env:
+          CARGO_REGISTRY_TOKEN: ${{ secrets.CARGO_REGISTRY_TOKEN }}
+        run: cargo publish --no-verify
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -1,52 +1,107 @@
 name: CI
 on:
-  # Only run when merging to master, or open/synchronize/reopen a PR.
-  push:
-    branches:
-      - master
  pull_request:
+  merge_group:
+
+env:
+  BROWSER_UI_TEST_VERSION: '0.19.0'

 jobs:
  test:
-    name: Test
    runs-on: ${{ matrix.os }}
    strategy:
      matrix:
-        build: [stable, beta, nightly, macos, windows, msrv]
        include:
-          - build: stable
+          - name: stable linux
            os: ubuntu-latest
            rust: stable
-          - build: beta
+            target: x86_64-unknown-linux-gnu
+          - name: beta linux
            os: ubuntu-latest
            rust: beta
-          - build: nightly
+            target: x86_64-unknown-linux-gnu
+          - name: nightly linux
            os: ubuntu-latest
            rust: nightly
-          - build: macos
+            target: x86_64-unknown-linux-gnu
+          - name: stable x86_64-unknown-linux-musl
+            os: ubuntu-22.04
+            rust: stable
+            target: x86_64-unknown-linux-musl
+          - name: stable x86_64 macos
            os: macos-latest
            rust: stable
-          - build: windows
+            target: x86_64-apple-darwin
+          - name: stable aarch64 macos
+            os: macos-latest
+            rust: stable
+            target: aarch64-apple-darwin
+          - name: stable windows-msvc
            os: windows-latest
            rust: stable
-          - build: msrv
-            os: ubuntu-20.04
+            target: x86_64-pc-windows-msvc
+          - name: msrv
+            os: ubuntu-22.04
            # sync MSRV with docs: guide/src/guide/installation.md and Cargo.toml
-            rust: 1.65.0
+            rust: 1.77.0
+            target: x86_64-unknown-linux-gnu
+    name: ${{ matrix.name }}
    steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
    - name: Install Rust
-      run: bash ci/install-rust.sh ${{ matrix.rust }}
+      run: bash ci/install-rust.sh ${{ matrix.rust }} ${{ matrix.target }}
    - name: Build and run tests
-      run: cargo test --locked
+      run: cargo test --locked --target ${{ matrix.target }}
    - name: Test no default
-      run: cargo test --no-default-features
+      run: cargo test --no-default-features --target ${{ matrix.target }}
+
+  aarch64-cross-builds:
+    runs-on: ubuntu-22.04
+    steps:
+    - uses: actions/checkout@v4
+    - name: Install Rust
+      run: bash ci/install-rust.sh stable aarch64-unknown-linux-musl
+    - name: Build
+      run: cargo build --locked --target aarch64-unknown-linux-musl

  rustfmt:
    name: Rustfmt
    runs-on: ubuntu-latest
    steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
    - name: Install Rust
      run: rustup update stable && rustup default stable && rustup component add rustfmt
    - run: cargo fmt --check
+
+  gui:
+    name: GUI tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Rust
+        run: bash ci/install-rust.sh stable x86_64-unknown-linux-gnu
+      - name: Install npm
+        uses: actions/setup-node@v3
+        with:
+          node-version: 20
+      - name: Install browser-ui-test
+        run: npm install browser-ui-test@"${BROWSER_UI_TEST_VERSION}"
+      - name: Build and run tests (+ GUI)
+        run: cargo test --locked --target x86_64-unknown-linux-gnu --test gui
+
+  # The success job is here to consolidate the total success/failure state of
+  # all other jobs. This job is then included in the GitHub branch protection
+  # rule which prevents merges unless all other jobs are passing. This makes
+  # it easier to manage the list of jobs via this yml file and to prevent
+  # accidentally adding new jobs without also updating the branch protections.
+  success:
+    name: Success gate
+    if: always()
+    needs:
+      - test
+      - rustfmt
+    runs-on: ubuntu-latest
+    steps:
+      - run: jq --exit-status 'all(.result == "success")' <<< '${{ toJson(needs) }}'
+      - name: Done
+        run: exit 0
--- a/.gitignore
+++ b/.gitignore
@@ -16,3 +16,8 @@ test_book/book/
 # Ignore Vim temporary and swap files.
 *.sw?
 *~
+
+# GUI tests
+node_modules
+package-lock.json
+package.json
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,255 @@
 # Changelog

+## mdBook 0.4.45
+[v0.4.44...v0.4.45](https://github.com/rust-lang/mdBook/compare/v0.4.44...v0.4.45)
+
+### Changed
+
+- Added context to error message when rustdoc is not found.
+  [#2545](https://github.com/rust-lang/mdBook/pull/2545)
+- Slightly changed the styling rules around margins of footnotes.
+  [#2524](https://github.com/rust-lang/mdBook/pull/2524)
+
+### Fixed
+
+- Fixed an issue where it would panic if a source_path is not set.
+  [#2550](https://github.com/rust-lang/mdBook/pull/2550)
+
+## mdBook 0.4.44
+[v0.4.43...v0.4.44](https://github.com/rust-lang/mdBook/compare/v0.4.43...v0.4.44)
+
+### Added
+
+- Added pre-built aarch64-apple-darwin binaries to the releases.
+  [#2500](https://github.com/rust-lang/mdBook/pull/2500)
+- `mdbook clean` now shows a summary of what it did.
+  [#2458](https://github.com/rust-lang/mdBook/pull/2458)
+- Added the `output.html.search.chapter` config setting to disable search indexing of individual chapters.
+  [#2533](https://github.com/rust-lang/mdBook/pull/2533)
+
+### Fixed
+
+- Fixed auto-scrolling the side-bar when loading a page with a `#` fragment URL.
+  [#2517](https://github.com/rust-lang/mdBook/pull/2517)
+- Fixed display of sidebar when javascript is disabled.
+  [#2529](https://github.com/rust-lang/mdBook/pull/2529)
+- Fixed the sidebar visibility getting out of sync with the button.
+  [#2532](https://github.com/rust-lang/mdBook/pull/2532)
+
+### Changed
+
+- ❗ Rust code block hidden lines now follow the same logic as rustdoc. This requires a space after the `#` symbol.
+  [#2530](https://github.com/rust-lang/mdBook/pull/2530)
+- ❗ Updated the Linux pre-built binaries which requires a newer version of glibc (2.34).
+  [#2523](https://github.com/rust-lang/mdBook/pull/2523)
+- Updated dependencies
+  [#2538](https://github.com/rust-lang/mdBook/pull/2538)
+  [#2539](https://github.com/rust-lang/mdBook/pull/2539)
+
+## mdBook 0.4.43
+[v0.4.42...v0.4.43](https://github.com/rust-lang/mdBook/compare/v0.4.42...v0.4.43)
+
+### Fixed
+
+- Fixed setting the title in `mdbook init` when no git user is configured.
+  [#2486](https://github.com/rust-lang/mdBook/pull/2486)
+
+### Changed
+
+- The Rust 2024 edition no longer needs `-Zunstable-options`.
+  [#2495](https://github.com/rust-lang/mdBook/pull/2495)
+
+## mdBook 0.4.42
+[v0.4.41...v0.4.42](https://github.com/rust-lang/mdBook/compare/v0.4.41...v0.4.42)
+
+### Fixed
+
+- Fixed chapter list folding.
+  [#2473](https://github.com/rust-lang/mdBook/pull/2473)
+
+## mdBook 0.4.41
+[v0.4.40...v0.4.41](https://github.com/rust-lang/mdBook/compare/v0.4.40...v0.4.41)
+
+**Note:** If you have a custom `index.hbs` theme file, you will need to update it to the latest version.
+
+### Added
+
+- Added preliminary support for Rust 2024 edition.
+  [#2398](https://github.com/rust-lang/mdBook/pull/2398)
+- Added a full example of the remove-emphasis preprocessor.
+  [#2464](https://github.com/rust-lang/mdBook/pull/2464)
+
+### Changed
+
+- Adjusted styling of clipboard/play icons.
+  [#2421](https://github.com/rust-lang/mdBook/pull/2421)
+- Updated to handlebars v6.
+  [#2416](https://github.com/rust-lang/mdBook/pull/2416)
+- Attr and section rules now have specific code highlighting.
+  [#2448](https://github.com/rust-lang/mdBook/pull/2448)
+- The sidebar is now loaded from a common file, significantly reducing the book size when there are many chapters.
+  [#2414](https://github.com/rust-lang/mdBook/pull/2414)
+- Updated dependencies.
+  [#2470](https://github.com/rust-lang/mdBook/pull/2470)
+
+### Fixed
+
+- Improved theme support when JavaScript is disabled.
+  [#2454](https://github.com/rust-lang/mdBook/pull/2454)
+- Fixed broken themes when localStorage has an invalid theme id.
+  [#2463](https://github.com/rust-lang/mdBook/pull/2463)
+- Adjusted the line-height of superscripts (and footnotes) to avoid adding extra space between lines.
+  [#2465](https://github.com/rust-lang/mdBook/pull/2465)
+
+## mdBook 0.4.40
+[v0.4.39...v0.4.40](https://github.com/rust-lang/mdBook/compare/v0.4.39...v0.4.40)
+
+### Fixed
+
+- Reverted the update to pulldown-cmark which broke the semver API.
+  [#2388](https://github.com/rust-lang/mdBook/pull/2388)
+
+## mdBook 0.4.39
+[v0.4.38...v0.4.39](https://github.com/rust-lang/mdBook/compare/v0.4.38...v0.4.39)
+
+### Fixed
+
+- Fixed the automatic deploy broken in the previous release.
+  [#2383](https://github.com/rust-lang/mdBook/pull/2383)
+
+## mdBook 0.4.38
+[v0.4.37...v0.4.38](https://github.com/rust-lang/mdBook/compare/v0.4.37...v0.4.38)
+
+### Added
+
+- Added `nix` to the default set of languages supported for syntax highlighting.
+  [#2262](https://github.com/rust-lang/mdBook/pull/2262)
+
+### Changed
+
+- The `output.html.curly-quotes` option has been renamed to `output.html.smart-punctuation` to better reflect what it does. The old option `curly-quotes` is kept for compatibility, but may be removed in the future.
+  [#2327](https://github.com/rust-lang/mdBook/pull/2327)
+- The file-watcher used in `mdbook serve` and `mdbook watch` now uses a poll-based watcher instead of the native operating system notifications. This should fix issues on various systems and environments, and more accurately detect when files change. The native watcher can still be used with the `--watcher native` CLI option.
+  [#2325](https://github.com/rust-lang/mdBook/pull/2325)
+- `mdbook test` output now includes color, and shows relative paths to the source.
+  [#2259](https://github.com/rust-lang/mdBook/pull/2259)
+- Updated dependencies, MSRV raised to 1.74
+  [#2350](https://github.com/rust-lang/mdBook/pull/2350)
+  [#2351](https://github.com/rust-lang/mdBook/pull/2351)
+  [#2378](https://github.com/rust-lang/mdBook/pull/2378)
+  [#2381](https://github.com/rust-lang/mdBook/pull/2381)
+
+### Fixed
+
+- Reduced memory allocation when copying files.
+  [#2355](https://github.com/rust-lang/mdBook/pull/2355)
+- Fixed the horizontal divider in `SUMMARY.md` from being indented into the previous nested section.
+  [#2364](https://github.com/rust-lang/mdBook/pull/2364)
+- Removed unnecessary `@import` in the CSS.
+  [#2260](https://github.com/rust-lang/mdBook/pull/2260)
+
+## mdBook 0.4.37
+[v0.4.36...v0.4.37](https://github.com/rust-lang/mdBook/compare/v0.4.36...v0.4.37)
+
+### Changed
+- ❗️ Updated the markdown parser. This brings in many changes to more closely follow the CommonMark spec. This may cause some small rendering changes. It is recommended to compare the output of the old and new version to check for changes. See <https://github.com/raphlinus/pulldown-cmark/releases/tag/v0.10.0> for more information.
+  [#2308](https://github.com/rust-lang/mdBook/pull/2308)
+- The warning about the legacy `src/theme` directory has been removed.
+  [#2263](https://github.com/rust-lang/mdBook/pull/2263)
+- Updated dependencies. MSRV raised to 1.71.0.
+  [#2283](https://github.com/rust-lang/mdBook/pull/2283)
+  [#2293](https://github.com/rust-lang/mdBook/pull/2293)
+  [#2297](https://github.com/rust-lang/mdBook/pull/2297)
+  [#2310](https://github.com/rust-lang/mdBook/pull/2310)
+  [#2309](https://github.com/rust-lang/mdBook/pull/2309)
+- Some internal performance/memory improvements.
+  [#2273](https://github.com/rust-lang/mdBook/pull/2273)
+  [#2290](https://github.com/rust-lang/mdBook/pull/2290)
+- Made the `pathdiff` dependency optional based on the `watch` feature.
+  [#2291](https://github.com/rust-lang/mdBook/pull/2291)
+
+### Fixed
+- The `s` shortcut key handler should not trigger when focus is in an HTML form.
+  [#2311](https://github.com/rust-lang/mdBook/pull/2311)
+
+## mdBook 0.4.36
+[v0.4.35...v0.4.36](https://github.com/rust-lang/mdBook/compare/v0.4.35...v0.4.36)
+
+### Added
+- Added Nim to the default highlighted languages.
+  [#2232](https://github.com/rust-lang/mdBook/pull/2232)
+- Added a small indicator for the sidebar resize handle.
+  [#2209](https://github.com/rust-lang/mdBook/pull/2209)
+
+### Changed
+- Updated dependencies. MSRV raised to 1.70.0.
+  [#2173](https://github.com/rust-lang/mdBook/pull/2173)
+  [#2250](https://github.com/rust-lang/mdBook/pull/2250)
+  [#2252](https://github.com/rust-lang/mdBook/pull/2252)
+
+### Fixed
+- Fixed blank column in print page when the sidebar was visible.
+  [#2235](https://github.com/rust-lang/mdBook/pull/2235)
+- Fixed indentation of code blocks when Javascript is disabled.
+  [#2162](https://github.com/rust-lang/mdBook/pull/2162)
+- Fixed a panic when `mdbook serve` or `mdbook watch` were given certain kinds of paths.
+  [#2229](https://github.com/rust-lang/mdBook/pull/2229)
+
+## mdBook 0.4.35
+[v0.4.34...v0.4.35](https://github.com/rust-lang/mdBook/compare/v0.4.34...v0.4.35)
+
+### Added
+- Added the `book.text-direction` setting for explicit support for right-to-left languages.
+  [#1641](https://github.com/rust-lang/mdBook/pull/1641)
+- Added `rel=prefetch` to the "next" links to potentially improve browser performance.
+  [#2168](https://github.com/rust-lang/mdBook/pull/2168)
+- Added a `.warning` CSS class which is styled for displaying warning blocks.
+  [#2187](https://github.com/rust-lang/mdBook/pull/2187)
+
+### Changed
+- Better support of the sidebar when JavaScript is disabled.
+  [#2175](https://github.com/rust-lang/mdBook/pull/2175)
+
+## mdBook 0.4.34
+[v0.4.33...v0.4.34](https://github.com/rust-lang/mdBook/compare/v0.4.33...v0.4.34)
+
+### Fixed
+- Fixed file change watcher failing on macOS with a large number of files.
+  [#2157](https://github.com/rust-lang/mdBook/pull/2157)
+
+## mdBook 0.4.33
+[v0.4.32...v0.4.33](https://github.com/rust-lang/mdBook/compare/v0.4.32...v0.4.33)
+
+### Added
+- The `color-scheme` CSS property is now set based on the light/dark theme, which applies some slight color differences in browser elements like scroll bars on some browsers.
+  [#2134](https://github.com/rust-lang/mdBook/pull/2134)
+
+### Fixed
+- Fixed watching of extra-watch-dirs when not running in the book root directory.
+  [#2146](https://github.com/rust-lang/mdBook/pull/2146)
+- Reverted the dependency update to the `toml` crate (again!). This was an unintentional breaking change in 0.4.32.
+  [#2021](https://github.com/rust-lang/mdBook/pull/2021)
+- Changed macOS change notifications to use the kqueue implementation which should fix some issues with repeated rebuilds when a file changed.
+  [#2152](https://github.com/rust-lang/mdBook/pull/2152)
+- Don't set a background color in the print page for code blocks in a header.
+  [#2150](https://github.com/rust-lang/mdBook/pull/2150)
+
+## mdBook 0.4.32
+[v0.4.31...v0.4.32](https://github.com/rust-lang/mdBook/compare/v0.4.31...v0.4.32)
+
+### Fixed
+- Fixed theme-color meta tag not syncing with the theme.
+  [#2118](https://github.com/rust-lang/mdBook/pull/2118)
+
+### Changed
+- Updated all dependencies.
+  [#2121](https://github.com/rust-lang/mdBook/pull/2121)
+  [#2122](https://github.com/rust-lang/mdBook/pull/2122)
+  [#2123](https://github.com/rust-lang/mdBook/pull/2123)
+  [#2124](https://github.com/rust-lang/mdBook/pull/2124)
+  [#2125](https://github.com/rust-lang/mdBook/pull/2125)
+  [#2126](https://github.com/rust-lang/mdBook/pull/2126)
+
 ## mdBook 0.4.31
 [v0.4.30...v0.4.31](https://github.com/rust-lang/mdBook/compare/v0.4.30...v0.4.31)

@@ -224,7 +474,7 @@
  [#1771](https://github.com/rust-lang/mdBook/pull/1771)
 - The 404 not-found page now includes the books title in the HTML title tag.
  [#1693](https://github.com/rust-lang/mdBook/pull/1693)
- Migrated to clap 3.0 which which handles CLI option parsing.
+- Migrated to clap 3.0 which handles CLI option parsing.
  [#1731](https://github.com/rust-lang/mdBook/pull/1731)

 ### Fixed
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -138,8 +138,23 @@ We generally strive to keep mdBook compatible with a relatively recent browser o
 That is, supporting Chrome, Safari, Firefox, Edge on Windows, macOS, Linux, iOS, and Android.
 If possible, do your best to avoid breaking older browser releases.

-Any change to the HTML or styling is encouraged to manually check on as many browsers and platforms that you can.
-Unfortunately at this time we don't have any automated UI or browser testing, so your assistance in testing is appreciated.
+GUI tests are checked with the GUI testsuite. To run it, you need to install `npm` first. Then run:
+
+```
+cargo test --test gui
+```
+
+The first time, it'll fail and ask you to install the `browser-ui-test` package. Install it then re-run the tests.
+
+If you want to disable the headless mode, use the `DISABLE_HEADLESS_TEST=1` environment variable:
+
+```
+cargo test --test gui -- --disable-headless-test
+```
+
+The GUI tests are in the directory `tests/gui` in text files with the `.goml` extension. These tests are run
+using a `node.js` framework called `browser-ui-test`. You can find documentation for this language on its
+[repository](https://github.com/GuillaumeGomez/browser-UI-test/blob/master/goml-script.md).

 ## Updating highlight.js

@@ -148,8 +163,28 @@ The following are instructions for updating [highlight.js](https://highlightjs.o
 1. Clone the repository at <https://github.com/highlightjs/highlight.js>
 1. Check out a tagged release (like `10.1.1`).
 1. Run `npm install`
-1. Run `node tools/build.js :common apache armasm coffeescript d handlebars haskell http julia nginx properties r scala x86asm yaml`
+1. Run `node tools/build.js :common apache armasm coffeescript d handlebars haskell http julia nginx nim nix properties r scala x86asm yaml`
 1. Compare the language list that it spits out to the one in [`syntax-highlighting.md`](https://github.com/camelid/mdBook/blob/master/guide/src/format/theme/syntax-highlighting.md). If any are missing, add them to the list and rebuild (and update these docs). If any are added to the common set, add them to `syntax-highlighting.md`.
 1. Copy `build/highlight.min.js` to mdbook's directory [`highlight.js`](https://github.com/rust-lang/mdBook/blob/master/src/theme/highlight.js).
 1. Be sure to check the highlight.js [CHANGES](https://github.com/highlightjs/highlight.js/blob/main/CHANGES.md) for any breaking changes. Breaking changes that would affect users will need to wait until the next major release.
 1. Build mdbook with the new file and build some books with the new version and compare the output with a variety of languages to see if anything changes. The [test_book](https://github.com/rust-lang/mdBook/tree/master/test_book) contains a chapter with many languages to examine.
+
+## Publishing new releases
+
+Instructions for mdBook maintainers to publish a new release:
+
+1. Create a PR to update the version and update the CHANGELOG:
+    1. Update the version in `Cargo.toml`
+    2. Run `cargo test` to verify that everything is passing, and to update `Cargo.lock`.
+    3. Double-check for any SemVer breaking changes.
+       Try [`cargo-semver-checks`](https://crates.io/crates/cargo-semver-checks), though beware that the current version of mdBook isn't properly adhering to SemVer due to the lack of `#[non_exhaustive]` and other issues. See https://github.com/rust-lang/mdBook/issues/1835.
+    4. Update `CHANGELOG.md` with any changes that users may be interested in.
+    5. Update `continuous-integration.md` to update the version number for the installation instructions.
+    6. Commit the changes, and open a PR.
+2. After the PR has been merged, create a release in GitHub. This can either be done in the GitHub web UI, or on the command-line:
+   ```bash
+   MDBOOK_VERS="`cargo read-manifest | jq -r .version`" ; \
+    gh release create -R rust-lang/mdbook v$MDBOOK_VERS \
+        --title v$MDBOOK_VERS \
+        --notes "See https://github.com/rust-lang/mdBook/blob/master/CHANGELOG.md#mdbook-${MDBOOK_VERS//.} for a complete list of changes."
+   ```
--- a/Cargo.lock
+++ b/Cargo.lock
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,9 @@
+[workspace]
+members = [".", "examples/remove-emphasis/mdbook-remove-emphasis"]
+
 [package]
 name = "mdbook"
-version = "0.4.31"
+version = "0.4.45"
 authors = [
    "Mathieu David <mathieudavid@mathieudavid.org>",
    "Michael-F-Bryan <michaelfbryan@gmail.com>",
@@ -14,45 +17,47 @@ license = "MPL-2.0"
 readme = "README.md"
 repository = "https://github.com/rust-lang/mdBook"
 description = "Creates a book from markdown files"
-rust-version = "1.65"
+rust-version = "1.77" # Keep in sync with installation.md and .github/workflows/main.yml

 [dependencies]
 anyhow = "1.0.71"
 chrono = { version = "0.4.24", default-features = false, features = ["clock"] }
-clap = { version = "4.2.7", features = ["cargo", "wrap_help"] }
-clap_complete = "4.2.3"
+clap = { version = "4.3.12", features = ["cargo", "wrap_help"] }
+clap_complete = "4.3.2"
 once_cell = "1.17.1"
-env_logger = "0.10.0"
-handlebars = "4.3.7"
+env_logger = "0.11.1"
+handlebars = "6.0"
 log = "0.4.17"
 memchr = "2.5.0"
-opener = "0.5.2"
-pulldown-cmark = { version = "0.9.3", default-features = false }
+opener = "0.7.0"
+pulldown-cmark = { version = "0.10.0", default-features = false, features = ["html"] } # Do not update, part of the public api.
 regex = "1.8.1"
 serde = { version = "1.0.163", features = ["derive"] }
 serde_json = "1.0.96"
-shlex = "1.1.0"
+shlex = "1.3.0"
 tempfile = "3.4.0"
-toml = "0.5.11"
+toml = "0.5.11" # Do not update, see https://github.com/rust-lang/mdBook/issues/2037
 topological-sort = "0.2.2"

 # Watch feature
-notify = { version = "5.1.0", optional = true }
-notify-debouncer-mini = { version = "0.2.1", optional = true }
+notify = { version = "8.0.0", optional = true }
+notify-debouncer-mini = { version = "0.6.0", optional = true }
 ignore = { version = "0.4.20", optional = true }
+pathdiff = { version = "0.2.1", optional = true }
+walkdir = { version = "2.3.3", optional = true }

 # Serve feature
 futures-util = { version = "0.3.28", optional = true }
 tokio = { version = "1.28.1", features = ["macros", "rt-multi-thread"], optional = true }
-warp = { version = "0.3.5", default-features = false, features = ["websocket"], optional = true }
+warp = { version = "0.3.6", default-features = false, features = ["websocket"], optional = true }

 # Search feature
 elasticlunr-rs = { version = "3.0.2", optional = true }
-ammonia = { version = "3.3.0", optional = true }
+ammonia = { version = "4.0.0", optional = true }

 [dev-dependencies]
 assert_cmd = "2.0.11"
-predicates = "2.1.5"
+predicates = "3.0.3"
 select = "0.6.0"
 semver = "1.0.17"
 pretty_assertions = "1.3.0"
@@ -60,7 +65,7 @@ walkdir = "2.3.3"

 [features]
 default = ["watch", "serve", "search"]
-watch = ["dep:notify", "dep:notify-debouncer-mini", "dep:ignore"]
+watch = ["dep:notify", "dep:notify-debouncer-mini", "dep:ignore", "dep:pathdiff", "dep:walkdir"]
 serve = ["dep:futures-util", "dep:tokio", "dep:warp"]
 search = ["dep:elasticlunr-rs", "dep:ammonia"]

@@ -71,3 +76,16 @@ name = "mdbook"
 [[example]]
 name = "nop-preprocessor"
 test = true
+
+[[example]]
+name = "remove-emphasis"
+path = "examples/remove-emphasis/test.rs"
+crate-type = ["lib"]
+test = true
+
+[[test]]
+harness = false
+test = false
+name = "gui"
+path = "tests/gui/runner.rs"
+crate-type = ["bin"]
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # mdBook

-[![Build Status](https://github.com/rust-lang/mdBook/workflows/CI/badge.svg?event=push)](https://github.com/rust-lang/mdBook/actions?workflow=CI)
+[![CI Status](https://github.com/rust-lang/mdBook/actions/workflows/main.yml/badge.svg)](https://github.com/rust-lang/mdBook/actions/workflows/main.yml)
 [![crates.io](https://img.shields.io/crates/v/mdbook.svg)](https://crates.io/crates/mdbook)
 [![LICENSE](https://img.shields.io/github/license/rust-lang/mdBook.svg)](LICENSE)

--- a/ci/install-hub.sh
+++ b/ci/install-hub.sh
@@ -1,24 +0,0 @@
-#!/usr/bin/env bash
-# Installs the `hub` executable into hub/bin
-set -ex
-case $1 in
-  ubuntu*)
-    curl -LsSf https://github.com/github/hub/releases/download/v2.12.8/hub-linux-amd64-2.12.8.tgz -o hub.tgz
-    mkdir hub
-    tar -xzvf hub.tgz --strip=1 -C hub
-    ;;
-  macos*)
-    curl -LsSf https://github.com/github/hub/releases/download/v2.12.8/hub-darwin-amd64-2.12.8.tgz -o hub.tgz
-    mkdir hub
-    tar -xzvf hub.tgz --strip=1 -C hub
-    ;;
-  windows*)
-    curl -LsSf https://github.com/github/hub/releases/download/v2.12.8/hub-windows-amd64-2.12.8.zip -o hub.zip
-    7z x hub.zip -ohub
-    ;;
-  *)
-    echo "OS should be first parameter, was: $1"
-    ;;
-esac
-
-echo "$PWD/hub/bin" >> $GITHUB_PATH
--- a/ci/install-rust.sh
+++ b/ci/install-rust.sh
@@ -22,6 +22,19 @@ then
        rustup component add llvm-tools-preview --toolchain=$TOOLCHAIN
        rustup component add rust-std-$TARGET --toolchain=$TOOLCHAIN
    fi
+    if [[ $TARGET == *"musl" ]]
+    then
+        # This is needed by libdbus-sys.
+        sudo apt update -y && sudo apt install musl-dev musl-tools -y
+    fi
+    if [[ $TARGET == "aarch64-unknown-linux-musl" ]]
+    then
+        echo CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_LINKER=rust-lld >> $GITHUB_ENV
+        # This `CC` is some nonsense needed for libdbus-sys (via opener).
+        # I don't know if this is really the right thing to do, but it seems to work.
+        sudo apt install gcc-aarch64-linux-gnu -y
+        echo CC=aarch64-linux-gnu-gcc >> $GITHUB_ENV
+    fi
 fi

 rustup default $TOOLCHAIN
--- a/ci/make-release-asset.sh
+++ b/ci/make-release-asset.sh
@@ -12,10 +12,6 @@ TAG=${GITHUB_REF#*/tags/}

 host=$(rustc -Vv | grep ^host: | sed -e "s/host: //g")
 target=$2
-if [ "$host" != "$target" ]
-then
-  export "CARGO_TARGET_$(echo $target | tr a-z- A-Z_)_LINKER"=rust-lld
-fi
 export CARGO_PROFILE_RELEASE_LTO=true
 cargo build --locked --bin mdbook --release --target $target
 cd target/$target/release
@@ -44,9 +40,10 @@ case $1 in
 esac
 cd ../..

-if [[ -z "$GITHUB_TOKEN" ]]
+if [[ -z "$GITHUB_ENV" ]]
 then
-  echo "$GITHUB_TOKEN not set, skipping deploy."
+  echo "GITHUB_ENV not set, run: gh release upload $TAG target/$asset"
 else
-  hub release edit -m "" --attach $asset $TAG
+  echo "MDBOOK_TAG=$TAG" >> $GITHUB_ENV
+  echo "MDBOOK_ASSET=target/$asset" >> $GITHUB_ENV
 fi
--- a/examples/nop-preprocessor.rs
+++ b/examples/nop-preprocessor.rs
@@ -26,7 +26,7 @@ fn main() {
    if let Some(sub_args) = matches.subcommand_matches("supports") {
        handle_supports(&preprocessor, sub_args);
    } else if let Err(e) = handle_preprocessing(&preprocessor) {
-        eprintln!("{}", e);
+        eprintln!("{e}");
        process::exit(1);
    }
 }
--- a/examples/remove-emphasis/.gitignore
+++ b/examples/remove-emphasis/.gitignore
@@ -0,0 +1 @@
+book
--- a/examples/remove-emphasis/book.toml
+++ b/examples/remove-emphasis/book.toml
@@ -0,0 +1,5 @@
+[book]
+title = "remove-emphasis"
+
+[preprocessor.remove-emphasis]
+command = "cargo run --manifest-path=mdbook-remove-emphasis/Cargo.toml --locked"
--- a/examples/remove-emphasis/mdbook-remove-emphasis/Cargo.toml
+++ b/examples/remove-emphasis/mdbook-remove-emphasis/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "mdbook-remove-emphasis"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+mdbook = { version = "0.4.40", path = "../../.." }
+pulldown-cmark = { version = "0.12.2", default-features = false }
+pulldown-cmark-to-cmark = "18.0.0"
+serde_json = "1.0.132"
--- a/examples/remove-emphasis/mdbook-remove-emphasis/src/main.rs
+++ b/examples/remove-emphasis/mdbook-remove-emphasis/src/main.rs
@@ -0,0 +1,82 @@
+//! This is a demonstration of an mdBook preprocessor which parses markdown
+//! and removes any instances of emphasis.
+
+use mdbook::book::{Book, Chapter};
+use mdbook::errors::Error;
+use mdbook::preprocess::{CmdPreprocessor, Preprocessor, PreprocessorContext};
+use mdbook::BookItem;
+use pulldown_cmark::{Event, Parser, Tag, TagEnd};
+use std::io;
+
+fn main() {
+    let mut args = std::env::args().skip(1);
+    match args.next().as_deref() {
+        Some("supports") => {
+            // Supports all renderers.
+            return;
+        }
+        Some(arg) => {
+            eprintln!("unknown argument: {arg}");
+            std::process::exit(1);
+        }
+        None => {}
+    }
+
+    if let Err(e) = handle_preprocessing() {
+        eprintln!("{}", e);
+        std::process::exit(1);
+    }
+}
+
+struct RemoveEmphasis;
+
+impl Preprocessor for RemoveEmphasis {
+    fn name(&self) -> &str {
+        "remove-emphasis"
+    }
+
+    fn run(&self, _ctx: &PreprocessorContext, mut book: Book) -> Result<Book, Error> {
+        let mut total = 0;
+        book.for_each_mut(|item| {
+            let BookItem::Chapter(ch) = item else {
+                return;
+            };
+            if ch.is_draft_chapter() {
+                return;
+            }
+            match remove_emphasis(&mut total, ch) {
+                Ok(s) => ch.content = s,
+                Err(e) => eprintln!("failed to process chapter: {e:?}"),
+            }
+        });
+        eprintln!("removed {total} emphasis");
+        Ok(book)
+    }
+}
+
+// ANCHOR: remove_emphasis
+fn remove_emphasis(num_removed_items: &mut usize, chapter: &mut Chapter) -> Result<String, Error> {
+    let mut buf = String::with_capacity(chapter.content.len());
+
+    let events = Parser::new(&chapter.content).filter(|e| match e {
+        Event::Start(Tag::Emphasis) | Event::Start(Tag::Strong) => {
+            *num_removed_items += 1;
+            false
+        }
+        Event::End(TagEnd::Emphasis) | Event::End(TagEnd::Strong) => false,
+        _ => true,
+    });
+
+    Ok(pulldown_cmark_to_cmark::cmark(events, &mut buf).map(|_| buf)?)
+}
+// ANCHOR_END: remove_emphasis
+
+pub fn handle_preprocessing() -> Result<(), Error> {
+    let pre = RemoveEmphasis;
+    let (ctx, book) = CmdPreprocessor::parse_input(io::stdin())?;
+
+    let processed_book = pre.run(&ctx, book)?;
+    serde_json::to_writer(io::stdout(), &processed_book)?;
+
+    Ok(())
+}
--- a/examples/remove-emphasis/src/SUMMARY.md
+++ b/examples/remove-emphasis/src/SUMMARY.md
@@ -0,0 +1,3 @@
+# Summary
+
+- [Chapter 1](./chapter_1.md)
--- a/examples/remove-emphasis/src/chapter_1.md
+++ b/examples/remove-emphasis/src/chapter_1.md
@@ -0,0 +1,3 @@
+# Chapter 1
+
+This has *light emphasis* and **bold emphasis**.
--- a/examples/remove-emphasis/test.rs
+++ b/examples/remove-emphasis/test.rs
@@ -0,0 +1,13 @@
+use mdbook::MDBook;
+
+#[test]
+fn remove_emphasis_works() {
+    // Tests that the remove-emphasis example works as expected.
+
+    // Workaround for https://github.com/rust-lang/mdBook/issues/1424
+    std::env::set_current_dir("examples/remove-emphasis").unwrap();
+    let book = MDBook::load(".").unwrap();
+    book.build().unwrap();
+    let ch1 = std::fs::read_to_string("book/chapter_1.html").unwrap();
+    assert!(ch1.contains("This has light emphasis and bold emphasis."));
+}
--- a/guide/book.toml
+++ b/guide/book.toml
@@ -8,6 +8,7 @@ language = "en"
 edition = "2018"

 [output.html]
+smart-punctuation = true
 mathjax-support = true
 site-url = "/mdBook/"
 git-repository-url = "https://github.com/rust-lang/mdBook/tree/master/guide"
--- a/guide/src/cli/README.md
+++ b/guide/src/cli/README.md
@@ -5,10 +5,10 @@ After you have [installed](../guide/installation.md) `mdbook`, you can run the `

 This following sections provide in-depth information on the different commands available.

-* [`mdbook init <directory>`](init.md) — Creates a new book with minimal boilerplate to start with.
-* [`mdbook build`](build.md) — Renders the book.
-* [`mdbook watch`](watch.md) — Rebuilds the book any time a source file changes.
-* [`mdbook serve`](serve.md) — Runs a web server to view the book, and rebuilds on changes.
-* [`mdbook test`](test.md) — Tests Rust code samples.
-* [`mdbook clean`](clean.md) — Deletes the rendered output.
-* [`mdbook completions`](completions.md) — Support for shell auto-completion.
+* [`mdbook init <directory>`](init.md) --- Creates a new book with minimal boilerplate to start with.
+* [`mdbook build`](build.md) --- Renders the book.
+* [`mdbook watch`](watch.md) --- Rebuilds the book any time a source file changes.
+* [`mdbook serve`](serve.md) --- Runs a web server to view the book, and rebuilds on changes.
+* [`mdbook test`](test.md) --- Tests Rust code samples.
+* [`mdbook clean`](clean.md) --- Deletes the rendered output.
+* [`mdbook completions`](completions.md) --- Support for shell auto-completion.
--- a/guide/src/cli/arg-watcher.md
+++ b/guide/src/cli/arg-watcher.md
@@ -0,0 +1,7 @@
+#### `--watcher`
+
+There are different backends used to determine when a file has changed.
+
+* `poll` (default) --- Checks for file modifications by scanning the filesystem every second.
+* `native` --- Uses the native operating system facilities to receive notifications when files change.
+  This can have less constant overhead, but may not be as reliable as the `poll` based watcher. See these issues for more information: [#383](https://github.com/rust-lang/mdBook/issues/383) [#1441](https://github.com/rust-lang/mdBook/issues/1441) [#1707](https://github.com/rust-lang/mdBook/issues/1707) [#2035](https://github.com/rust-lang/mdBook/issues/2035) [#2102](https://github.com/rust-lang/mdBook/issues/2102)
--- a/guide/src/cli/build.md
+++ b/guide/src/cli/build.md
@@ -7,8 +7,8 @@ mdbook build
 ```

 It will try to parse your `SUMMARY.md` file to understand the structure of your
-book and fetch the corresponding files. Note that files mentioned in `SUMMARY.md`
-but not present will be created.
+book and fetch the corresponding files. Note that this will also create files
+mentioned in `SUMMARY.md` which are not yet present.

 The rendered output will maintain the same directory structure as the source for
 convenience. Large books will therefore remain structured when rendered.
@@ -22,12 +22,12 @@ root instead of the current working directory.
 mdbook build path/to/book
 ```

-#### --open
+#### `--open`

 When you use the `--open` (`-o`) flag, mdbook will open the rendered book in
 your default web browser after building it.

-#### --dest-dir
+#### `--dest-dir`

 The `--dest-dir` (`-d`) option allows you to change the output directory for the
 book. Relative paths are interpreted relative to the book's root directory. If
--- a/guide/src/cli/clean.md
+++ b/guide/src/cli/clean.md
@@ -16,7 +16,7 @@ root instead of the current working directory.
 mdbook clean path/to/book
 ```

-#### --dest-dir
+#### `--dest-dir`

 The `--dest-dir` (`-d`) option allows you to override the book's output
 directory, which will be deleted by this command. Relative paths are interpreted
@@ -27,4 +27,4 @@ value of the `build.build-dir` key in `book.toml`, or to `./book`.
 mdbook clean --dest-dir=path/to/book
 ```

-`path/to/book` could be absolute or relative.
+`path/to/book` could be absolute or relative.
--- a/guide/src/cli/completions.md
+++ b/guide/src/cli/completions.md
@@ -6,7 +6,11 @@ This means when you type `mdbook` in your shell, you can then press your shell's
 The completions first need to be installed for your shell:

 ```bash
+# bash
 mdbook completions bash > ~/.local/share/bash-completion/completions/mdbook
+# oh-my-zsh
+mdbook completions zsh > ~/.oh-my-zsh/completions/_mdbook
+autoload -U compinit && compinit
 ```

 The command prints a completion script for the given shell.
--- a/guide/src/cli/init.md
+++ b/guide/src/cli/init.md
@@ -45,7 +45,7 @@ instead of the current working directory.
 mdbook init path/to/book
 ```

-#### --theme
+#### `--theme`

 When you use the `--theme` flag, the default theme will be copied into a
 directory called `theme` in your source directory so that you can modify it.
@@ -53,7 +53,7 @@ directory called `theme` in your source directory so that you can modify it.
 The theme is selectively overwritten, this means that if you don't want to
 overwrite a specific file, just delete it and the default file will be used.

-#### --title
+#### `--title`

 Specify a title for the book. If not supplied, an interactive prompt will ask for 
 a title. 
@@ -62,7 +62,7 @@ a title.
 mdbook init --title="my amazing book"
 ```

-#### --ignore
+#### `--ignore`

 Create a `.gitignore` file configured to ignore the `book` directory created when [building] a book. 
 If not supplied, an interactive prompt will ask whether it should be created.
@@ -77,6 +77,6 @@ mdbook init --ignore=git

 [building]: build.md

-#### --force
+#### `--force`

 Skip the prompts to create a `.gitignore` and for the title for the book.
--- a/guide/src/cli/serve.md
+++ b/guide/src/cli/serve.md
@@ -32,18 +32,20 @@ The `serve` hostname defaults to `localhost`, and the port defaults to `3000`. E
 mdbook serve path/to/book -p 8000 -n 127.0.0.1 
 ```

-#### --open
+#### `--open`

 When you use the `--open` (`-o`) flag, mdbook will open the book in your
 default web browser after starting the server.

-#### --dest-dir
+#### `--dest-dir`

 The `--dest-dir` (`-d`) option allows you to change the output directory for the
 book. Relative paths are interpreted relative to the book's root directory. If
 not specified it will default to the value of the `build.build-dir` key in
 `book.toml`, or to `./book`.

+{{#include arg-watcher.md}}
+
 #### Specify exclude patterns

 The `serve` command will not automatically trigger a build for files listed in
--- a/guide/src/cli/test.md
+++ b/guide/src/cli/test.md
@@ -6,8 +6,7 @@ of code examples that could get outdated. Therefore it is very important for
 them to be able to automatically test these code examples.

 mdBook supports a `test` command that will run all available tests in a book. At
-the moment, only rustdoc tests are supported, but this may be expanded upon in
-the future.
+the moment, only Rust tests are supported.

 #### Disable tests on a code block

@@ -38,7 +37,7 @@ instead of the current working directory.
 mdbook test path/to/book
 ```

-#### --library-path
+#### `--library-path`

 The `--library-path` (`-L`) option allows you to add directories to the library
 search path used by `rustdoc` when it builds and tests the examples. Multiple
@@ -55,14 +54,14 @@ mdbook test my-book -L target/debug/deps/
 See the `rustdoc` command-line [documentation](https://doc.rust-lang.org/rustdoc/command-line-arguments.html#-l--library-path-where-to-look-for-dependencies)
 for more information.

-#### --dest-dir
+#### `--dest-dir`

 The `--dest-dir` (`-d`) option allows you to change the output directory for the
 book. Relative paths are interpreted relative to the book's root directory. If
 not specified it will default to the value of the `build.build-dir` key in
 `book.toml`, or to `./book`.

-#### --chapter
+#### `--chapter`

 The `--chapter` (`-c`) option allows you to test a specific chapter of the
-book using the chapter name or the relative path to the chapter.
+book using the chapter name or the relative path to the chapter.
--- a/guide/src/cli/watch.md
+++ b/guide/src/cli/watch.md
@@ -15,18 +15,19 @@ root instead of the current working directory.
 mdbook watch path/to/book
 ```

-#### --open
+#### `--open`

 When you use the `--open` (`-o`) option, mdbook will open the rendered book in
 your default web browser.

-#### --dest-dir
+#### `--dest-dir`

 The `--dest-dir` (`-d`) option allows you to change the output directory for the
 book. Relative paths are interpreted relative to the book's root directory. If
 not specified it will default to the value of the `build.build-dir` key in
 `book.toml`, or to `./book`.

+{{#include arg-watcher.md}}

 #### Specify exclude patterns

--- a/guide/src/continuous-integration.md
+++ b/guide/src/continuous-integration.md
@@ -21,7 +21,7 @@ A simple approach would be to use the popular `curl` CLI tool to download the ex

 ```sh
 mkdir bin
-curl -sSL https://github.com/rust-lang/mdBook/releases/download/v0.4.31/mdbook-v0.4.31-x86_64-unknown-linux-gnu.tar.gz | tar -xz --directory=bin
+curl -sSL https://github.com/rust-lang/mdBook/releases/download/v0.4.45/mdbook-v0.4.45-x86_64-unknown-linux-gnu.tar.gz | tar -xz --directory=bin
 bin/mdbook build
 ```

@@ -51,13 +51,13 @@ cargo install mdbook --no-default-features --features search --vers "^0.4" --loc

 This includes several recommended options:

-* `--no-default-features` — Disables features like the HTTP server used by `mdbook serve` that is likely not needed on CI.
+* `--no-default-features` --- Disables features like the HTTP server used by `mdbook serve` that is likely not needed on CI.
  This will speed up the build time significantly.
-* `--features search` — Disabling default features means you should then manually enable features that you want, such as the built-in [search] capability.
-* `--vers "^0.4"` — This will install the most recent version of the `0.4` series.
+* `--features search` --- Disabling default features means you should then manually enable features that you want, such as the built-in [search] capability.
+* `--vers "^0.4"` --- This will install the most recent version of the `0.4` series.
  However, versions after like `0.5.0` won't be installed, as they may break your build.
  Cargo will automatically upgrade mdBook if you have an older version already installed.
-* `--locked` — This will use the dependencies that were used when mdBook was released.
+* `--locked` --- This will use the dependencies that were used when mdBook was released.
  Without `--locked`, it will use the latest version of all dependencies, which may include some fixes since the last release, but may also (rarely) cause build problems.

 You will likely want to investigate caching options, as building mdBook can be somewhat slow.
--- a/guide/src/for_developers/backends.md
+++ b/guide/src/for_developers/backends.md
@@ -287,7 +287,7 @@ like this:
 +             if cfg.deny_odds && num_words % 2 == 1 {
 +               eprintln!("{} has an odd number of words!", ch.name);
 +               process::exit(1);
-              }
+             }
          }
      }
  }
--- a/guide/src/for_developers/preprocessors.md
+++ b/guide/src/for_developers/preprocessors.md
@@ -68,33 +68,10 @@ The following code block shows how to remove all emphasis from markdown,
 without accidentally breaking the document.

 ```rust
-fn remove_emphasis(
-    num_removed_items: &mut usize,
-    chapter: &mut Chapter,
-) -> Result<String> {
-    let mut buf = String::with_capacity(chapter.content.len());
-
-    let events = Parser::new(&chapter.content).filter(|e| {
-        let should_keep = match *e {
-            Event::Start(Tag::Emphasis)
-            | Event::Start(Tag::Strong)
-            | Event::End(Tag::Emphasis)
-            | Event::End(Tag::Strong) => false,
-            _ => true,
-        };
-        if !should_keep {
-            *num_removed_items += 1;
-        }
-        should_keep
-    });
-
-    cmark(events, &mut buf, None).map(|_| buf).map_err(|err| {
-        Error::from(format!("Markdown serialization failed: {}", err))
-    })
-}
+{{#rustdoc_include ../../../examples/remove-emphasis/mdbook-remove-emphasis/src/main.rs:remove_emphasis}}
 ```

-For everything else, have a look [at the complete example][example].
+Take a look at the [full example source][emphasis-example] for more details.

 ## Implementing a preprocessor with a different language

@@ -122,11 +99,10 @@ if __name__ == '__main__':
 ```


-
+[emphasis-example]: https://github.com/rust-lang/mdBook/tree/master/examples/remove-emphasis/
 [preprocessor-docs]: https://docs.rs/mdbook/latest/mdbook/preprocess/trait.Preprocessor.html
 [pc]: https://crates.io/crates/pulldown-cmark
 [pctc]: https://crates.io/crates/pulldown-cmark-to-cmark
-[example]: https://github.com/rust-lang/mdBook/blob/master/examples/nop-preprocessor.rs
 [an example no-op preprocessor]: https://github.com/rust-lang/mdBook/blob/master/examples/nop-preprocessor.rs
 [`CmdPreprocessor::parse_input()`]: https://docs.rs/mdbook/latest/mdbook/preprocess/trait.Preprocessor.html#method.parse_input
 [`Book::for_each_mut()`]: https://docs.rs/mdbook/latest/mdbook/book/struct.Book.html#method.for_each_mut
--- a/guide/src/format/configuration/general.md
+++ b/guide/src/format/configuration/general.md
@@ -46,6 +46,9 @@ This is general information about your book.
  `src` directly under the root folder. But this is configurable with the `src`
  key in the configuration file.
 - **language:** The main language of the book, which is used as a language attribute `<html lang="en">` for example.
+  This is also used to derive the direction of text (RTL, LTR) within the book.
+- **text-direction**: The direction of text in the book: Left-to-right (LTR) or Right-to-left (RTL). Possible values: `ltr`, `rtl`.
+  When not specified, the text direction is derived from the book's `language` attribute.

 **book.toml**
 ```toml
@@ -55,6 +58,7 @@ authors = ["John Doe", "Jane Doe"]
 description = "The example book covers examples."
 src = "my-src"  # the source files will be found in `root/my-src` instead of `root/src`
 language = "en"
+text-direction = "ltr"
 ```

 ### Rust options
@@ -68,7 +72,7 @@ edition = "2015"   # the default edition for code blocks
 ```

 - **edition**: Rust edition to use by default for the code snippets. Default
-  is "2015". Individual code blocks can be controlled with the `edition2015`, 
+  is `"2015"`. Individual code blocks can be controlled with the `edition2015`,
  `edition2018` or `edition2021` annotations, such as:

  ~~~text
@@ -97,7 +101,7 @@ extra-watch-dirs = []             # directories to watch for triggering builds
  will be created when the book is built (i.e. `create-missing = true`). If this
  is `false` then the build process will instead exit with an error if any files
  do not exist.
- **use-default-preprocessors:** Disable the default preprocessors of (`links` &
+- **use-default-preprocessors:** Disable the default preprocessors (of `links` &
  `index`) by setting this option to `false`.

  If you have the same, and/or other preprocessors declared via their table
@@ -111,4 +115,4 @@ extra-watch-dirs = []             # directories to watch for triggering builds
    `use-default-preprocessors` that `links` it will run.
 - **extra-watch-dirs**: A list of paths to directories that will be watched in
  the `watch` and `serve` commands. Changes to files under these directories will
-  trigger rebuilds. Useful if your book depends on files outside its `src` directory.
+  trigger rebuilds. Useful if your book depends on files outside its `src` directory.
--- a/guide/src/format/configuration/renderers.md
+++ b/guide/src/format/configuration/renderers.md
@@ -4,9 +4,9 @@ Renderers (also called "backends") are responsible for creating the output of th

 The following backends are built-in:

-* [`html`](#html-renderer-options) — This renders the book to HTML.
+* [`html`](#html-renderer-options) --- This renders the book to HTML.
  This is enabled by default if no other `[output]` tables are defined in `book.toml`.
-* [`markdown`](#markdown-renderer) — This outputs the book as markdown after running the preprocessors.
+* [`markdown`](#markdown-renderer) --- This outputs the book as markdown after running the preprocessors.
  This is useful for debugging preprocessors.

 The community has developed several backends.
@@ -97,7 +97,7 @@ description = "The example book covers examples."
 theme = "my-theme"
 default-theme = "light"
 preferred-dark-theme = "navy"
-curly-quotes = true
+smart-punctuation = true
 mathjax-support = false
 copy-fonts = true
 additional-css = ["custom.css", "custom2.css"]
@@ -120,10 +120,12 @@ The following configuration options are available:
  'Change Theme' dropdown. Defaults to `light`.
 - **preferred-dark-theme:** The default dark theme. This theme will be used if
  the browser requests the dark version of the site via the
-  ['prefers-color-scheme'](https://developer.mozilla.org/en-US/docs/Web/CSS/@media/prefers-color-scheme)
+  [`prefers-color-scheme`](https://developer.mozilla.org/en-US/docs/Web/CSS/@media/prefers-color-scheme)
  CSS media query. Defaults to `navy`.
- **curly-quotes:** Convert straight quotes to curly quotes, except for those
-  that occur in code blocks and code spans. Defaults to `false`.
+- **smart-punctuation:** Converts quotes to curly quotes, `...` to `…`, `--` to en-dash, and `---` to em-dash.
+  See [Smart Punctuation](../markdown.md#smart-punctuation).
+  Defaults to `false`.
+- **curly-quotes:** Deprecated alias for `smart-punctuation`.
 - **mathjax-support:** Adds support for [MathJax](../mathjax.md). Defaults to
  `false`.
 - **copy-fonts:** (**Deprecated**) If `true` (the default), mdBook uses its built-in fonts which are copied to the output directory.
@@ -279,6 +281,20 @@ copy-js = true           # include Javascript code for search
 - **copy-js:** Copy JavaScript files for the search implementation to the output
  directory. Defaults to `true`.

+#### `[output.html.search.chapter]`
+
+The [`output.html.search.chapter`] table provides the ability to modify search settings per chapter or directory. Each key is the path to the chapter source file or directory, and the value is a table of settings to apply to that path. This will merge recursively, with more specific paths taking precedence.
+
+```toml
+[output.html.search.chapter]
+# Disables search indexing for all chapters in the `appendix` directory.
+"appendix" = { enable = false }
+# Enables search indexing for just this one appendix chapter.
+"appendix/glossary.md" = { enable = true }
+```
+
+- **enable:** Enables or disables search indexing for the given chapters. Defaults to `true`. This does not override the overall `output.html.search.enable` setting; that must be `true` for any search functionality to be enabled. Be cautious when disabling indexing for chapters because that can potentially lead to user confusion when they search for terms and expect them to be found. This should only be used in exceptional circumstances where keeping the chapter in the index will cause issues with the quality of the search results.
+
 ### `[output.html.redirect]`

 The `[output.html.redirect]` table provides a way to add redirects.
--- a/guide/src/format/markdown.md
+++ b/guide/src/format/markdown.md
@@ -73,14 +73,14 @@ Linking to a URL or local file is easy:
 ```markdown
 Use [mdBook](https://github.com/rust-lang/mdBook). 

-Read about [mdBook](mdBook.md).
+Read about [mdBook](mdbook.md).

 A bare url: <https://www.rust-lang.org>.
 ```

 Use [mdBook](https://github.com/rust-lang/mdBook). 

-Read about [mdBook](mdBook.md).
+Read about [mdBook](mdbook.md).

 A bare url: <https://www.rust-lang.org>.

@@ -214,12 +214,12 @@ characters:
 So, no need to manually enter those Unicode characters!

 This feature is disabled by default.
-To enable it, see the [`output.html.curly-quotes`] config option.
+To enable it, see the [`output.html.smart-punctuation`] config option.

 [strikethrough]: https://github.github.com/gfm/#strikethrough-extension-
 [tables]: https://github.github.com/gfm/#tables-extension-
 [task list extension]: https://github.github.com/gfm/#task-list-items-extension-
-[`output.html.curly-quotes`]: configuration/renderers.md#html-renderer-options
+[`output.html.smart-punctuation`]: configuration/renderers.md#html-renderer-options

 ### Heading attributes

@@ -232,4 +232,4 @@ Example:

 This makes the level 1 heading with the content `Example heading`, ID `first`, and classes `class1` and `class2`. Note that the attributes should be space-separated.

-More information can be found in the [heading attrs spec page](https://github.com/raphlinus/pulldown-cmark/blob/master/specs/heading_attrs.txt).
+More information can be found in the [heading attrs spec page](https://github.com/raphlinus/pulldown-cmark/blob/master/pulldown-cmark/specs/heading_attrs.txt).
--- a/guide/src/format/mdbook.md
+++ b/guide/src/format/mdbook.md
@@ -4,7 +4,8 @@

 There is a feature in mdBook that lets you hide code lines by prepending them with a specific prefix.

-For the Rust language, you can use the `#` character as a prefix which will hide lines [like you would with Rustdoc][rustdoc-hide].
+For the Rust language, you can prefix lines with `# ` (`#` followed by a space) to hide them [like you would with Rustdoc][rustdoc-hide].
+This prefix can be escaped with `##` to prevent the hiding of a line that should begin with the literal string `# ` (see [Rustdoc's docs][rustdoc-hide] for more details)

 [rustdoc-hide]: https://doc.rust-lang.org/stable/rustdoc/write-documentation/documentation-tests.html#hiding-portions-of-the-example

@@ -112,16 +113,16 @@ panic!("oops!");
 These are particularly important when using [`mdbook test`] to test Rust examples.
 These use the same attributes as [rustdoc attributes], with a few additions:

-* `editable` — Enables the [editor].
-* `noplayground` — Removes the play button, but will still be tested.
-* `mdbook-runnable` — Forces the play button to be displayed.
+* `editable` --- Enables the [editor].
+* `noplayground` --- Removes the play button, but will still be tested.
+* `mdbook-runnable` --- Forces the play button to be displayed.
  This is intended to be combined with the `ignore` attribute for examples that should not be tested, but you want to allow the reader to run.
-* `ignore` — Will not be tested and no play button is shown, but it is still highlighted as Rust syntax.
-* `should_panic` — When executed, it should produce a panic.
-* `no_run` — The code is compiled when tested, but it is not run.
+* `ignore` --- Will not be tested and no play button is shown, but it is still highlighted as Rust syntax.
+* `should_panic` --- When executed, it should produce a panic.
+* `no_run` --- The code is compiled when tested, but it is not run.
  The play button is also not shown.
-* `compile_fail` — The code should fail to compile.
-* `edition2015`, `edition2018`, `edition2021` — Forces the use of a specific Rust edition.
+* `compile_fail` --- The code should fail to compile.
+* `edition2015`, `edition2018`, `edition2021` --- Forces the use of a specific Rust edition.
  See [`rust.edition`] to set this globally.

 [`mdbook test`]: ../cli/test.md
@@ -314,3 +315,51 @@ contents (sidebar) by including a `\{{#title ...}}` near the top of the page.
 ```hbs
 \{{#title My Title}}
 ```
+
+## HTML classes provided by mdBook
+
+<img class="right" src="images/rust-logo-blk.svg" alt="The Rust logo">
+
+### `class="left"` and `"right"`
+
+These classes are provided by default, for inline HTML to float images.
+
+```html
+<img class="right" src="images/rust-logo-blk.svg" alt="The Rust logo">
+```
+
+### `class="hidden"`
+
+HTML tags with class `hidden` will not be shown.
+
+```html
+<div class="hidden">This will not be seen.</div>
+```
+
+<div class="hidden">This will not be seen.</div>
+
+### `class="warning"`
+
+To make a warning or similar note stand out, wrap it in a warning div.
+
+```html
+<div class="warning">
+
+This is a bad thing that you should pay attention to.
+
+Warning blocks should be used sparingly in documentation, to avoid "warning
+fatigue," where people are trained to ignore them because they usually don't
+matter for what they're doing.
+
+</div>
+```
+
+<div class="warning">
+
+This is a bad thing that you should pay attention to.
+
+Warning blocks should be used sparingly in documentation, to avoid "warning
+fatigue," where people are trained to ignore them because they usually don't
+matter for what they're doing.
+
+</div>
--- a/guide/src/format/summary.md
+++ b/guide/src/format/summary.md
@@ -29,11 +29,12 @@ to be ignored at best, or may cause an error when attempting to build the book.
   - [First Chapter](relative/path/to/markdown2.md)
   ```

-1. ***Part Title*** - Headers can be used as a title for the following numbered
-   chapters. This can be used to logically separate different sections
-   of the book. The title is rendered as unclickable text.
-   Titles are optional, and the numbered chapters can be broken into as many
-   parts as desired.
+1. ***Part Title*** -
+   Level 1 headers can be used as a title for the following numbered chapters.
+   This can be used to logically separate different sections of the book.
+   The title is rendered as unclickable text.
+   Titles are optional, and the numbered chapters can be broken into as many parts as desired.
+   Part titles must be h1 headers (one `#`), other heading levels are ignored.
   ```markdown
   # My Part Title

--- a/guide/src/format/theme/index-hbs.md
+++ b/guide/src/format/theme/index-hbs.md
@@ -18,7 +18,7 @@ handlebars template you can access this information by using
 Here is a list of the properties that are exposed:

 - ***language*** Language of the book in the form `en`, as specified in `book.toml` (if not specified, defaults to `en`). To use in <code
-  class="language-html">\<html lang="{{ language }}"></code> for example.
+  class="language-html">\<html lang=\"{{ language }}\"></code> for example.
 - ***title*** Title used for the current page. This is identical to `{{ chapter_title }} - {{ book_title }}` unless `book_title` is not set in which case it just defaults to the `chapter_title`.
 - ***book_title*** Title of the book, as specified in `book.toml`
 - ***chapter_title*** Title of the current chapter, as listed in `SUMMARY.md`
@@ -79,7 +79,7 @@ var chapters = {{chapters}};

 ### 2. previous / next

-The previous and next helpers expose a `link` and `name` property to the
+The previous and next helpers expose a `link` and `title` property to the
 previous and next chapters.

 They are used like this
@@ -87,7 +87,7 @@ They are used like this
 ```handlebars
 {{#previous}}
    <a href="{{link}}" class="nav-chapters previous">
-        <i class="fa fa-angle-left"></i>
+        <i class="fa fa-angle-left"></i> {{title}}
    </a>
 {{/previous}}
 ```
--- a/guide/src/format/theme/syntax-highlighting.md
+++ b/guide/src/format/theme/syntax-highlighting.md
@@ -44,6 +44,8 @@ your own `highlight.js` file:
 - makefile
 - markdown
 - nginx
+- nim
+- nix
 - objectivec
 - perl
 - php
--- a/guide/src/guide/installation.md
+++ b/guide/src/guide/installation.md
@@ -20,7 +20,7 @@ To make it easier to run, put the path to the binary into your `PATH`.

 To build the `mdbook` executable from source, you will first need to install Rust and Cargo.
 Follow the instructions on the [Rust installation page].
-mdBook currently requires at least Rust version 1.65.
+mdBook currently requires at least Rust version 1.77.

 Once you have installed Rust, the following command can be used to build and install mdBook:

@@ -30,6 +30,9 @@ cargo install mdbook

 This will automatically download mdBook from [crates.io], build it, and install it in Cargo's global binary directory (`~/.cargo/bin/` by default).

+You can run `cargo install mdbook` again whenever you want to update to a new version.
+That command will check if there is a newer version, and re-install mdBook if a newer version is found.
+
 To uninstall, run the command `cargo uninstall mdbook`.

 [Rust installation page]: https://www.rust-lang.org/tools/install
@@ -47,6 +50,8 @@ cargo install --git https://github.com/rust-lang/mdBook.git mdbook

 Again, make sure to add the Cargo bin directory to your `PATH`.

+## Modifying and contributing
+
 If you are interested in making modifications to mdBook itself, check out the [Contributing Guide] for more information.

 [Contributing Guide]: https://github.com/rust-lang/mdBook/blob/master/CONTRIBUTING.md
--- a/src/book/book.rs
+++ b/src/book/book.rs
@@ -18,11 +18,11 @@ pub fn load_book<P: AsRef<Path>>(src_dir: P, cfg: &BuildConfig) -> Result<Book>

    let mut summary_content = String::new();
    File::open(&summary_md)
-        .with_context(|| format!("Couldn't open SUMMARY.md in {:?} directory", src_dir))?
+        .with_context(|| format!("Couldn't open SUMMARY.md in {src_dir:?} directory"))?
        .read_to_string(&mut summary_content)?;

    let summary = parse_summary(&summary_content)
-        .with_context(|| format!("Summary parsing failed for file={:?}", summary_md))?;
+        .with_context(|| format!("Summary parsing failed for file={summary_md:?}"))?;

    if cfg.create_missing {
        create_missing(src_dir, &summary).with_context(|| "Unable to create missing chapters")?;
@@ -160,8 +160,21 @@ pub struct Chapter {
    /// Nested items.
    pub sub_items: Vec<BookItem>,
    /// The chapter's location, relative to the `SUMMARY.md` file.
+    ///
+    /// **Note**: After the index preprocessor runs, any README files will be
+    /// modified to be `index.md`. If you need access to the actual filename
+    /// on disk, use [`Chapter::source_path`] instead.
+    ///
+    /// This is `None` for a draft chapter.
    pub path: Option<PathBuf>,
    /// The chapter's source file, relative to the `SUMMARY.md` file.
+    ///
+    /// **Note**: Beware that README files will internally be treated as
+    /// `index.md` via the [`Chapter::path`] field. The `source_path` field
+    /// exists if you need access to the true file path.
+    ///
+    /// This is `None` for a draft chapter, or a synthetically generated
+    /// chapter that has no file on disk.
    pub source_path: Option<PathBuf>,
    /// An ordered list of the names of each chapter above this one in the hierarchy.
    pub parent_names: Vec<String>,
@@ -329,7 +342,7 @@ impl<'a> Iterator for BookItems<'a> {
 impl Display for Chapter {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        if let Some(ref section_number) = self.number {
-            write!(f, "{} ", section_number)?;
+            write!(f, "{section_number} ")?;
        }

        write!(f, "{}", self.name)
@@ -339,7 +352,6 @@ impl Display for Chapter {
 #[cfg(test)]
 mod tests {
    use super::*;
-    use std::io::Write;
    use tempfile::{Builder as TempFileBuilder, TempDir};

    const DUMMY_SRC: &str = "
--- a/src/book/mod.rs
+++ b/src/book/mod.rs
@@ -15,10 +15,10 @@ pub use self::init::BookBuilder;
 pub use self::summary::{parse_summary, Link, SectionNumber, Summary, SummaryItem};

 use log::{debug, error, info, log_enabled, trace, warn};
-use std::io::Write;
-use std::path::PathBuf;
+use std::ffi::OsString;
+use std::io::{IsTerminal, Write};
+use std::path::{Path, PathBuf};
 use std::process::Command;
-use std::string::ToString;
 use tempfile::Builder as TempFileBuilder;
 use toml::Value;
 use topological_sort::TopologicalSort;
@@ -71,22 +71,28 @@ impl MDBook {

        config.update_from_env();

-        if config
-            .html_config()
-            .map_or(false, |html| html.google_analytics.is_some())
-        {
-            warn!(
-                "The output.html.google-analytics field has been deprecated; \
-                 it will be removed in a future release.\n\
-                 Consider placing the appropriate site tag code into the \
-                 theme/head.hbs file instead.\n\
-                 The tracking code may be found in the Google Analytics Admin page.\n\
-               "
-            );
+        if let Some(html_config) = config.html_config() {
+            if html_config.google_analytics.is_some() {
+                warn!(
+                    "The output.html.google-analytics field has been deprecated; \
+                     it will be removed in a future release.\n\
+                     Consider placing the appropriate site tag code into the \
+                     theme/head.hbs file instead.\n\
+                     The tracking code may be found in the Google Analytics Admin page.\n\
+                   "
+                );
+            }
+            if html_config.curly_quotes {
+                warn!(
+                    "The output.html.curly-quotes field has been renamed to \
+                     output.html.smart-punctuation.\n\
+                     Use the new name in book.toml to remove this warning."
+                );
+            }
        }

        if log_enabled!(log::Level::Trace) {
-            for line in format!("Config: {:#?}", config).lines() {
+            for line in format!("Config: {config:#?}").lines() {
                trace!("{}", line);
            }
        }
@@ -259,10 +265,18 @@ impl MDBook {
    /// Run `rustdoc` tests on a specific chapter of the book, linking against the provided libraries.
    /// If `chapter` is `None`, all tests will be run.
    pub fn test_chapter(&mut self, library_paths: Vec<&str>, chapter: Option<&str>) -> Result<()> {
-        let library_args: Vec<&str> = (0..library_paths.len())
-            .map(|_| "-L")
-            .zip(library_paths.into_iter())
-            .flat_map(|x| vec![x.0, x.1])
+        let cwd = std::env::current_dir()?;
+        let library_args: Vec<OsString> = library_paths
+            .into_iter()
+            .flat_map(|path| {
+                let path = Path::new(path);
+                let path = if path.is_relative() {
+                    cwd.join(path).into_os_string()
+                } else {
+                    path.to_path_buf().into_os_string()
+                };
+                [OsString::from("-L"), path]
+            })
            .collect();

        let temp_dir = TempFileBuilder::new().prefix("mdbook-").tempdir()?;
@@ -289,6 +303,7 @@ impl MDBook {
            .collect();
        let (book, _) = self.preprocess_book(&TestRenderer)?;

+        let color_output = std::io::stderr().is_terminal();
        let mut failed = false;
        for item in book.iter() {
            if let BookItem::Chapter(ref ch) = *item {
@@ -314,7 +329,10 @@ impl MDBook {
                tmpf.write_all(ch.content.as_bytes())?;

                let mut cmd = Command::new("rustdoc");
-                cmd.arg(&path).arg("--test").args(&library_args);
+                cmd.current_dir(temp_dir.path())
+                    .arg(chapter_path)
+                    .arg("--test")
+                    .args(&library_args);

                if let Some(edition) = self.config.rust.edition {
                    match edition {
@@ -327,11 +345,20 @@ impl MDBook {
                        RustEdition::E2021 => {
                            cmd.args(["--edition", "2021"]);
                        }
+                        RustEdition::E2024 => {
+                            cmd.args(["--edition", "2024"]);
+                        }
                    }
                }

+                if color_output {
+                    cmd.args(["--color", "always"]);
+                }
+
                debug!("running {:?}", cmd);
-                let output = cmd.output()?;
+                let output = cmd
+                    .output()
+                    .with_context(|| "failed to execute `rustdoc`")?;

                if !output.status.success() {
                    failed = true;
@@ -458,15 +485,13 @@ fn determine_preprocessors(config: &Config) -> Result<Vec<Box<dyn Preprocessor>>
            if let Some(before) = table.get("before") {
                let before = before.as_array().ok_or_else(|| {
                    Error::msg(format!(
-                        "Expected preprocessor.{}.before to be an array",
-                        name
+                        "Expected preprocessor.{name}.before to be an array"
                    ))
                })?;
                for after in before {
                    let after = after.as_str().ok_or_else(|| {
                        Error::msg(format!(
-                            "Expected preprocessor.{}.before to contain strings",
-                            name
+                            "Expected preprocessor.{name}.before to contain strings"
                        ))
                    })?;

@@ -485,16 +510,12 @@ fn determine_preprocessors(config: &Config) -> Result<Vec<Box<dyn Preprocessor>>

            if let Some(after) = table.get("after") {
                let after = after.as_array().ok_or_else(|| {
-                    Error::msg(format!(
-                        "Expected preprocessor.{}.after to be an array",
-                        name
-                    ))
+                    Error::msg(format!("Expected preprocessor.{name}.after to be an array"))
                })?;
                for before in after {
                    let before = before.as_str().ok_or_else(|| {
                        Error::msg(format!(
-                            "Expected preprocessor.{}.after to contain strings",
-                            name
+                            "Expected preprocessor.{name}.after to contain strings"
                        ))
                    })?;

@@ -556,7 +577,7 @@ fn get_custom_preprocessor_cmd(key: &str, table: &Value) -> String {
        .get("command")
        .and_then(Value::as_str)
        .map(ToString::to_string)
-        .unwrap_or_else(|| format!("mdbook-{}", key))
+        .unwrap_or_else(|| format!("mdbook-{key}"))
 }

 fn interpret_custom_renderer(key: &str, table: &Value) -> Box<CmdRenderer> {
@@ -567,7 +588,7 @@ fn interpret_custom_renderer(key: &str, table: &Value) -> Box<CmdRenderer> {
        .and_then(Value::as_str)
        .map(ToString::to_string);

-    let command = table_dot_command.unwrap_or_else(|| format!("mdbook-{}", key));
+    let command = table_dot_command.unwrap_or_else(|| format!("mdbook-{key}"));

    Box::new(CmdRenderer::new(key.to_string(), command))
 }
@@ -605,7 +626,7 @@ fn preprocessor_should_run(
 mod tests {
    use super::*;
    use std::str::FromStr;
-    use toml::value::{Table, Value};
+    use toml::value::Table;

    #[test]
    fn config_defaults_to_html_renderer_if_empty() {
@@ -761,7 +782,7 @@ mod tests {
                for preprocessor in &preprocessors {
                    eprintln!("  {}", preprocessor.name());
                }
-                panic!("{} should come before {}", before, after);
+                panic!("{before} should come before {after}");
            }
        };

--- a/src/book/summary.rs
+++ b/src/book/summary.rs
@@ -1,10 +1,9 @@
 use crate::errors::*;
 use log::{debug, trace, warn};
-use memchr::{self, Memchr};
-use pulldown_cmark::{self, Event, HeadingLevel, Tag};
+use memchr::Memchr;
+use pulldown_cmark::{DefaultBrokenLinkCallback, Event, HeadingLevel, Tag, TagEnd};
 use serde::{Deserialize, Serialize};
 use std::fmt::{self, Display, Formatter};
-use std::iter::FromIterator;
 use std::ops::{Deref, DerefMut};
 use std::path::{Path, PathBuf};

@@ -163,7 +162,7 @@ impl From<Link> for SummaryItem {
 /// > match the following regex: "[^<>\n[]]+".
 struct SummaryParser<'a> {
    src: &'a str,
-    stream: pulldown_cmark::OffsetIter<'a, 'a>,
+    stream: pulldown_cmark::OffsetIter<'a, DefaultBrokenLinkCallback>,
    offset: usize,

    /// We can't actually put an event back into the `OffsetIter` stream, so instead we store it
@@ -210,7 +209,7 @@ macro_rules! collect_events {
 }

 impl<'a> SummaryParser<'a> {
-    fn new(text: &str) -> SummaryParser<'_> {
+    fn new(text: &'a str) -> SummaryParser<'a> {
        let pulldown_parser = pulldown_cmark::Parser::new(text).into_offset_iter();

        SummaryParser {
@@ -265,7 +264,12 @@ impl<'a> SummaryParser<'a> {
        loop {
            match self.next_event() {
                Some(ev @ Event::Start(Tag::List(..)))
-                | Some(ev @ Event::Start(Tag::Heading(HeadingLevel::H1, ..))) => {
+                | Some(
+                    ev @ Event::Start(Tag::Heading {
+                        level: HeadingLevel::H1,
+                        ..
+                    }),
+                ) => {
                    if is_prefix {
                        // we've finished prefix chapters and are at the start
                        // of the numbered section.
@@ -275,8 +279,8 @@ impl<'a> SummaryParser<'a> {
                        bail!(self.parse_error("Suffix chapters cannot be followed by a list"));
                    }
                }
-                Some(Event::Start(Tag::Link(_type, href, _title))) => {
-                    let link = self.parse_link(href.to_string());
+                Some(Event::Start(Tag::Link { dest_url, .. })) => {
+                    let link = self.parse_link(dest_url.to_string());
                    items.push(SummaryItem::Link(link));
                }
                Some(Event::Rule) => items.push(SummaryItem::Separator),
@@ -304,10 +308,13 @@ impl<'a> SummaryParser<'a> {
                    break;
                }

-                Some(Event::Start(Tag::Heading(HeadingLevel::H1, ..))) => {
+                Some(Event::Start(Tag::Heading {
+                    level: HeadingLevel::H1,
+                    ..
+                })) => {
                    debug!("Found a h1 in the SUMMARY");

-                    let tags = collect_events!(self.stream, end Tag::Heading(HeadingLevel::H1, ..));
+                    let tags = collect_events!(self.stream, end TagEnd::Heading(HeadingLevel::H1));
                    Some(stringify_events(tags))
                }

@@ -336,7 +343,7 @@ impl<'a> SummaryParser<'a> {
    /// Finishes parsing a link once the `Event::Start(Tag::Link(..))` has been opened.
    fn parse_link(&mut self, href: String) -> Link {
        let href = href.replace("%20", " ");
-        let link_content = collect_events!(self.stream, end Tag::Link(..));
+        let link_content = collect_events!(self.stream, end TagEnd::Link);
        let name = stringify_events(link_content);

        let path = if href.is_empty() {
@@ -377,7 +384,12 @@ impl<'a> SummaryParser<'a> {
                }
                // The expectation is that pulldown cmark will terminate a paragraph before a new
                // heading, so we can always count on this to return without skipping headings.
-                Some(ev @ Event::Start(Tag::Heading(HeadingLevel::H1, ..))) => {
+                Some(
+                    ev @ Event::Start(Tag::Heading {
+                        level: HeadingLevel::H1,
+                        ..
+                    }),
+                ) => {
                    // we're starting a new part
                    self.back(ev);
                    break;
@@ -398,7 +410,7 @@ impl<'a> SummaryParser<'a> {

                    // Skip over the contents of this tag
                    while let Some(event) = self.next_event() {
-                        if event == Event::End(other_tag.clone()) {
+                        if event == Event::End(other_tag.clone().into()) {
                            break;
                        }
                    }
@@ -469,7 +481,7 @@ impl<'a> SummaryParser<'a> {

                    last_item.nested_items = sub_items;
                }
-                Some(Event::End(Tag::List(..))) => break,
+                Some(Event::End(TagEnd::List(..))) => break,
                Some(_) => {}
                None => break,
            }
@@ -486,8 +498,8 @@ impl<'a> SummaryParser<'a> {
        loop {
            match self.next_event() {
                Some(Event::Start(Tag::Paragraph)) => continue,
-                Some(Event::Start(Tag::Link(_type, href, _title))) => {
-                    let mut link = self.parse_link(href.to_string());
+                Some(Event::Start(Tag::Link { dest_url, .. })) => {
+                    let mut link = self.parse_link(dest_url.to_string());

                    let mut number = parent.clone();
                    number.0.push(num_existing_items as u32 + 1);
@@ -529,14 +541,18 @@ impl<'a> SummaryParser<'a> {
    fn parse_title(&mut self) -> Option<String> {
        loop {
            match self.next_event() {
-                Some(Event::Start(Tag::Heading(HeadingLevel::H1, ..))) => {
+                Some(Event::Start(Tag::Heading {
+                    level: HeadingLevel::H1,
+                    ..
+                })) => {
                    debug!("Found a h1 in the SUMMARY");

-                    let tags = collect_events!(self.stream, end Tag::Heading(HeadingLevel::H1, ..));
+                    let tags = collect_events!(self.stream, end TagEnd::Heading(HeadingLevel::H1));
                    return Some(stringify_events(tags));
                }
                // Skip a HTML element such as a comment line.
-                Some(Event::Html(_)) => {}
+                Some(Event::Html(_) | Event::InlineHtml(_))
+                | Some(Event::Start(Tag::HtmlBlock) | Event::End(TagEnd::HtmlBlock)) => {}
                // Otherwise, no title.
                Some(ev) => {
                    self.back(ev);
@@ -567,11 +583,13 @@ fn get_last_link(links: &mut [SummaryItem]) -> Result<(usize, &mut Link)> {
        .iter_mut()
        .enumerate()
        .filter_map(|(i, item)| item.maybe_link_mut().map(|l| (i, l)))
-        .rev()
-        .next()
-        .ok_or_else(||
-            anyhow::anyhow!("Unable to get last link because the list of SummaryItems doesn't contain any Links")
+        .next_back()
+        .ok_or_else(|| {
+            anyhow::anyhow!(
+                "Unable to get last link because the list of SummaryItems \
+                 doesn't contain any Links"
            )
+        })
 }

 /// Removes the styling from a list of Markdown events and returns just the
@@ -598,7 +616,7 @@ impl Display for SectionNumber {
            write!(f, "0")
        } else {
            for item in &self.0 {
-                write!(f, "{}.", item)?;
+                write!(f, "{item}.")?;
            }
            Ok(())
        }
@@ -744,8 +762,8 @@ mod tests {
        let _ = parser.stream.next(); // Discard opening paragraph

        let href = match parser.stream.next() {
-            Some((Event::Start(Tag::Link(_type, href, _title)), _range)) => href.to_string(),
-            other => panic!("Unreachable, {:?}", other),
+            Some((Event::Start(Tag::Link { dest_url, .. }), _range)) => dest_url.to_string(),
+            other => panic!("Unreachable, {other:?}"),
        };

        let got = parser.parse_link(href);
--- a/src/cmd/clean.rs
+++ b/src/cmd/clean.rs
@@ -2,8 +2,9 @@ use super::command_prelude::*;
 use crate::get_book_dir;
 use anyhow::Context;
 use mdbook::MDBook;
-use std::fs;
+use std::mem::take;
 use std::path::PathBuf;
+use std::{fmt, fs};

 // Create clap subcommand arguments
 pub fn make_subcommand() -> Command {
@@ -23,10 +24,88 @@ pub fn execute(args: &ArgMatches) -> mdbook::errors::Result<()> {
        None => book.root.join(&book.config.build.build_dir),
    };

-    if dir_to_remove.exists() {
-        fs::remove_dir_all(&dir_to_remove)
-            .with_context(|| "Unable to remove the build directory")?;
-    }
+    let removed = Clean::new(&dir_to_remove)?;
+    println!("{removed}");

    Ok(())
 }
+
+/// Formats a number of bytes into a human readable SI-prefixed size.
+/// Returns a tuple of `(quantity, units)`.
+pub fn human_readable_bytes(bytes: u64) -> (f32, &'static str) {
+    static UNITS: [&str; 7] = ["B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB"];
+    let bytes = bytes as f32;
+    let i = ((bytes.log2() / 10.0) as usize).min(UNITS.len() - 1);
+    (bytes / 1024_f32.powi(i as i32), UNITS[i])
+}
+
+#[derive(Debug)]
+pub struct Clean {
+    num_files_removed: u64,
+    num_dirs_removed: u64,
+    total_bytes_removed: u64,
+}
+
+impl Clean {
+    fn new(dir: &PathBuf) -> mdbook::errors::Result<Clean> {
+        let mut files = vec![dir.clone()];
+        let mut children = Vec::new();
+        let mut num_files_removed = 0;
+        let mut num_dirs_removed = 0;
+        let mut total_bytes_removed = 0;
+
+        if dir.exists() {
+            while !files.is_empty() {
+                for file in files {
+                    if let Ok(meta) = file.metadata() {
+                        // Note: This can over-count bytes removed for hard-linked
+                        // files. It also under-counts since it only counts the exact
+                        // byte sizes and not the block sizes.
+                        total_bytes_removed += meta.len();
+                    }
+                    if file.is_file() {
+                        num_files_removed += 1;
+                    } else if file.is_dir() {
+                        num_dirs_removed += 1;
+                        for entry in fs::read_dir(file)? {
+                            children.push(entry?.path());
+                        }
+                    }
+                }
+                files = take(&mut children);
+            }
+            fs::remove_dir_all(&dir).with_context(|| "Unable to remove the build directory")?;
+        }
+
+        Ok(Clean {
+            num_files_removed,
+            num_dirs_removed,
+            total_bytes_removed,
+        })
+    }
+}
+
+impl fmt::Display for Clean {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "Removed ")?;
+        match (self.num_files_removed, self.num_dirs_removed) {
+            (0, 0) => write!(f, "0 files")?,
+            (0, 1) => write!(f, "1 directory")?,
+            (0, 2..) => write!(f, "{} directories", self.num_dirs_removed)?,
+            (1, _) => write!(f, "1 file")?,
+            (2.., _) => write!(f, "{} files", self.num_files_removed)?,
+        }
+
+        if self.total_bytes_removed == 0 {
+            Ok(())
+        } else {
+            // Don't show a fractional number of bytes.
+            if self.total_bytes_removed < 1024 {
+                write!(f, ", {}B total", self.total_bytes_removed)
+            } else {
+                let (bytes, unit) = human_readable_bytes(self.total_bytes_removed);
+                write!(f, ", {bytes:.2}{unit} total")
+            }
+        }
+    }
+}
--- a/src/cmd/command_prelude.rs
+++ b/src/cmd/command_prelude.rs
@@ -36,6 +36,20 @@ pub trait CommandExt: Sized {
    fn arg_open(self) -> Self {
        self._arg(arg!(-o --open "Opens the compiled book in a web browser"))
    }
+
+    #[cfg(any(feature = "watch", feature = "serve"))]
+    fn arg_watcher(self) -> Self {
+        #[cfg(feature = "watch")]
+        return self._arg(
+            Arg::new("watcher")
+                .long("watcher")
+                .value_parser(["poll", "native"])
+                .default_value("poll")
+                .help("The filesystem watching technique"),
+        );
+        #[cfg(not(feature = "watch"))]
+        return self;
+    }
 }

 impl CommandExt for Command {
--- a/src/cmd/init.rs
+++ b/src/cmd/init.rs
@@ -74,9 +74,9 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
    if let Some(author) = get_author_name() {
        debug!("Obtained user name from gitconfig: {:?}", author);
        config.book.authors.push(author);
-        builder.with_config(config);
    }

+    builder.with_config(config);
    builder.build()?;
    println!("\nAll done, no errors...");

--- a/src/cmd/serve.rs
+++ b/src/cmd/serve.rs
@@ -6,7 +6,6 @@ use clap::builder::NonEmptyStringValueParser;
 use futures_util::sink::SinkExt;
 use futures_util::StreamExt;
 use mdbook::errors::*;
-use mdbook::utils;
 use mdbook::utils::fs::get_404_output_file;
 use mdbook::MDBook;
 use std::net::{SocketAddr, ToSocketAddrs};
@@ -43,18 +42,19 @@ pub fn make_subcommand() -> Command {
                .help("Port to use for HTTP connections"),
        )
        .arg_open()
+        .arg_watcher()
 }

 // Serve command implementation
 pub fn execute(args: &ArgMatches) -> Result<()> {
    let book_dir = get_book_dir(args);
-    let mut book = MDBook::load(book_dir)?;
+    let mut book = MDBook::load(&book_dir)?;

    let port = args.get_one::<String>("port").unwrap();
    let hostname = args.get_one::<String>("hostname").unwrap();
    let open_browser = args.get_flag("open");

-    let address = format!("{}:{}", hostname, port);
+    let address = format!("{hostname}:{port}");

    let update_config = |book: &mut MDBook| {
        book.config
@@ -89,7 +89,7 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
        serve(build_dir, sockaddr, reload_tx, &file_404);
    });

-    let serving_url = format!("http://{}", address);
+    let serving_url = format!("http://{address}");
    info!("Serving on: {}", serving_url);

    if open_browser {
@@ -97,23 +97,12 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
    }

    #[cfg(feature = "watch")]
-    watch::trigger_on_change(&book, move |paths, book_dir| {
-        info!("Files changed: {:?}", paths);
-        info!("Building book...");
-
-        // FIXME: This area is really ugly because we need to re-set livereload :(
-        let result = MDBook::load(book_dir).and_then(|mut b| {
-            update_config(&mut b);
-            b.build()
-        });
-
-        if let Err(e) = result {
-            error!("Unable to load the book");
-            utils::log_backtrace(&e);
-        } else {
+    {
+        let watcher = watch::WatcherKind::from_str(args.get_one::<String>("watcher").unwrap());
+        watch::rebuild_on_change(watcher, &book_dir, &update_config, &move || {
            let _ = tx.send(Message::text("reload"));
-        }
-    });
+        });
+    }

    let _ = thread_handle.join();

--- a/src/cmd/test.rs
+++ b/src/cmd/test.rs
@@ -1,7 +1,7 @@
 use super::command_prelude::*;
 use crate::get_book_dir;
 use clap::builder::NonEmptyStringValueParser;
-use clap::{Arg, ArgAction, ArgMatches, Command};
+use clap::ArgAction;
 use mdbook::errors::Result;
 use mdbook::MDBook;
 use std::path::PathBuf;
--- a/src/cmd/watch.rs
+++ b/src/cmd/watch.rs
@@ -1,13 +1,11 @@
 use super::command_prelude::*;
 use crate::{get_book_dir, open};
-use ignore::gitignore::Gitignore;
 use mdbook::errors::Result;
-use mdbook::utils;
 use mdbook::MDBook;
 use std::path::{Path, PathBuf};
-use std::sync::mpsc::channel;
-use std::thread::sleep;
-use std::time::Duration;
+
+mod native;
+mod poller;

 // Create clap subcommand arguments
 pub fn make_subcommand() -> Command {
@@ -16,12 +14,28 @@ pub fn make_subcommand() -> Command {
        .arg_dest_dir()
        .arg_root_dir()
        .arg_open()
+        .arg_watcher()
+}
+
+pub enum WatcherKind {
+    Poll,
+    Native,
+}
+
+impl WatcherKind {
+    pub fn from_str(s: &str) -> WatcherKind {
+        match s {
+            "poll" => WatcherKind::Poll,
+            "native" => WatcherKind::Native,
+            _ => panic!("unsupported watcher {s}"),
+        }
+    }
 }

 // Watch command implementation
 pub fn execute(args: &ArgMatches) -> Result<()> {
    let book_dir = get_book_dir(args);
-    let mut book = MDBook::load(book_dir)?;
+    let mut book = MDBook::load(&book_dir)?;

    let update_config = |book: &mut MDBook| {
        if let Some(dest_dir) = args.get_one::<PathBuf>("dest-dir") {
@@ -40,42 +54,21 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
        open(path);
    }

-    trigger_on_change(&book, |paths, book_dir| {
-        info!("Files changed: {:?}\nBuilding book...\n", paths);
-        let result = MDBook::load(book_dir).and_then(|mut b| {
-            update_config(&mut b);
-            b.build()
-        });
-
-        if let Err(e) = result {
-            error!("Unable to build the book");
-            utils::log_backtrace(&e);
-        }
-    });
+    let watcher = WatcherKind::from_str(args.get_one::<String>("watcher").unwrap());
+    rebuild_on_change(watcher, &book_dir, &update_config, &|| {});

    Ok(())
 }

-fn remove_ignored_files(book_root: &Path, paths: &[PathBuf]) -> Vec<PathBuf> {
-    if paths.is_empty() {
-        return vec![];
-    }
-
-    match find_gitignore(book_root) {
-        Some(gitignore_path) => {
-            let (ignore, err) = Gitignore::new(&gitignore_path);
-            if let Some(err) = err {
-                warn!(
-                    "error reading gitignore `{}`: {err}",
-                    gitignore_path.display()
-                );
-            }
-            filter_ignored_files(ignore, paths)
-        }
-        None => {
-            // There is no .gitignore file.
-            paths.iter().map(|path| path.to_path_buf()).collect()
-        }
+pub fn rebuild_on_change(
+    kind: WatcherKind,
+    book_dir: &Path,
+    update_config: &dyn Fn(&mut MDBook),
+    post_build: &dyn Fn(),
+) {
+    match kind {
+        WatcherKind::Poll => self::poller::rebuild_on_change(book_dir, update_config, post_build),
+        WatcherKind::Native => self::native::rebuild_on_change(book_dir, update_config, post_build),
    }
 }

@@ -85,92 +78,3 @@ fn find_gitignore(book_root: &Path) -> Option<PathBuf> {
        .map(|p| p.join(".gitignore"))
        .find(|p| p.exists())
 }
-
-fn filter_ignored_files(ignore: Gitignore, paths: &[PathBuf]) -> Vec<PathBuf> {
-    paths
-        .iter()
-        .filter(|path| {
-            !ignore
-                .matched_path_or_any_parents(path, path.is_dir())
-                .is_ignore()
-        })
-        .map(|path| path.to_path_buf())
-        .collect()
-}
-
-/// Calls the closure when a book source file is changed, blocking indefinitely.
-pub fn trigger_on_change<F>(book: &MDBook, closure: F)
-where
-    F: Fn(Vec<PathBuf>, &Path),
-{
-    use notify::RecursiveMode::*;
-
-    // Create a channel to receive the events.
-    let (tx, rx) = channel();
-
-    let mut debouncer = match notify_debouncer_mini::new_debouncer(Duration::from_secs(1), None, tx)
-    {
-        Ok(d) => d,
-        Err(e) => {
-            error!("Error while trying to watch the files:\n\n\t{:?}", e);
-            std::process::exit(1)
-        }
-    };
-    let watcher = debouncer.watcher();
-
-    // Add the source directory to the watcher
-    if let Err(e) = watcher.watch(&book.source_dir(), Recursive) {
-        error!("Error while watching {:?}:\n    {:?}", book.source_dir(), e);
-        std::process::exit(1);
-    };
-
-    let _ = watcher.watch(&book.theme_dir(), Recursive);
-
-    // Add the book.toml file to the watcher if it exists
-    let _ = watcher.watch(&book.root.join("book.toml"), NonRecursive);
-
-    for dir in &book.config.build.extra_watch_dirs {
-        let path = dir.canonicalize().unwrap();
-        if let Err(e) = watcher.watch(&path, Recursive) {
-            error!(
-                "Error while watching extra directory {:?}:\n    {:?}",
-                path, e
-            );
-            std::process::exit(1);
-        }
-    }
-
-    info!("Listening for changes...");
-
-    loop {
-        let first_event = rx.recv().unwrap();
-        sleep(Duration::from_millis(50));
-        let other_events = rx.try_iter();
-
-        let all_events = std::iter::once(first_event).chain(other_events);
-
-        let paths: Vec<_> = all_events
-            .filter_map(|event| match event {
-                Ok(events) => Some(events),
-                Err(errors) => {
-                    for error in errors {
-                        log::warn!("error while watching for changes: {error}");
-                    }
-                    None
-                }
-            })
-            .flatten()
-            .map(|event| event.path)
-            .collect();
-
-        // If we are watching files outside the current repository (via extra-watch-dirs), then they are definitionally
-        // ignored by gitignore. So we handle this case by including such files into the watched paths list.
-        let any_external_paths = paths.iter().filter(|p| !p.starts_with(&book.root)).cloned();
-        let mut paths = remove_ignored_files(&book.root, &paths[..]);
-        paths.extend(any_external_paths);
-
-        if !paths.is_empty() {
-            closure(paths, &book.root);
-        }
-    }
-}
--- a/src/cmd/watch/native.rs
+++ b/src/cmd/watch/native.rs
@@ -0,0 +1,189 @@
+//! A filesystem watcher using native operating system facilities.
+
+use ignore::gitignore::Gitignore;
+use mdbook::MDBook;
+use std::path::{Path, PathBuf};
+use std::sync::mpsc::channel;
+use std::thread::sleep;
+use std::time::Duration;
+
+pub fn rebuild_on_change(
+    book_dir: &Path,
+    update_config: &dyn Fn(&mut MDBook),
+    post_build: &dyn Fn(),
+) {
+    use notify::RecursiveMode::*;
+
+    let mut book = MDBook::load(book_dir).unwrap_or_else(|e| {
+        error!("failed to load book: {e}");
+        std::process::exit(1);
+    });
+
+    // Create a channel to receive the events.
+    let (tx, rx) = channel();
+
+    let mut debouncer = match notify_debouncer_mini::new_debouncer(Duration::from_secs(1), tx) {
+        Ok(d) => d,
+        Err(e) => {
+            error!("Error while trying to watch the files:\n\n\t{:?}", e);
+            std::process::exit(1)
+        }
+    };
+    let watcher = debouncer.watcher();
+
+    // Add the source directory to the watcher
+    if let Err(e) = watcher.watch(&book.source_dir(), Recursive) {
+        error!("Error while watching {:?}:\n    {:?}", book.source_dir(), e);
+        std::process::exit(1);
+    };
+
+    let _ = watcher.watch(&book.theme_dir(), Recursive);
+
+    // Add the book.toml file to the watcher if it exists
+    let _ = watcher.watch(&book.root.join("book.toml"), NonRecursive);
+
+    for dir in &book.config.build.extra_watch_dirs {
+        let path = book.root.join(dir);
+        let canonical_path = path.canonicalize().unwrap_or_else(|e| {
+            error!("Error while watching extra directory {path:?}:\n    {e}");
+            std::process::exit(1);
+        });
+
+        if let Err(e) = watcher.watch(&canonical_path, Recursive) {
+            error!(
+                "Error while watching extra directory {:?}:\n    {:?}",
+                canonical_path, e
+            );
+            std::process::exit(1);
+        }
+    }
+
+    info!("Listening for changes...");
+
+    loop {
+        let first_event = rx.recv().unwrap();
+        sleep(Duration::from_millis(50));
+        let other_events = rx.try_iter();
+
+        let all_events = std::iter::once(first_event).chain(other_events);
+
+        let paths: Vec<_> = all_events
+            .filter_map(|event| match event {
+                Ok(events) => Some(events),
+                Err(error) => {
+                    log::warn!("error while watching for changes: {error}");
+                    None
+                }
+            })
+            .flatten()
+            .map(|event| event.path)
+            .collect();
+
+        // If we are watching files outside the current repository (via extra-watch-dirs), then they are definitionally
+        // ignored by gitignore. So we handle this case by including such files into the watched paths list.
+        let any_external_paths = paths.iter().filter(|p| !p.starts_with(&book.root)).cloned();
+        let mut paths = remove_ignored_files(&book.root, &paths[..]);
+        paths.extend(any_external_paths);
+
+        if !paths.is_empty() {
+            info!("Files changed: {paths:?}");
+            match MDBook::load(book_dir) {
+                Ok(mut b) => {
+                    update_config(&mut b);
+                    if let Err(e) = b.build() {
+                        error!("failed to build the book: {e:?}");
+                    } else {
+                        post_build();
+                    }
+                    book = b;
+                }
+                Err(e) => error!("failed to load book config: {e:?}"),
+            }
+        }
+    }
+}
+
+fn remove_ignored_files(book_root: &Path, paths: &[PathBuf]) -> Vec<PathBuf> {
+    if paths.is_empty() {
+        return vec![];
+    }
+
+    match super::find_gitignore(book_root) {
+        Some(gitignore_path) => {
+            let (ignore, err) = Gitignore::new(&gitignore_path);
+            if let Some(err) = err {
+                warn!(
+                    "error reading gitignore `{}`: {err}",
+                    gitignore_path.display()
+                );
+            }
+            filter_ignored_files(ignore, paths)
+        }
+        None => {
+            // There is no .gitignore file.
+            paths.iter().map(|path| path.to_path_buf()).collect()
+        }
+    }
+}
+
+// Note: The usage of `canonicalize` may encounter occasional failures on the Windows platform, presenting a potential risk.
+// For more details, refer to [Pull Request #2229](https://github.com/rust-lang/mdBook/pull/2229#discussion_r1408665981).
+fn filter_ignored_files(ignore: Gitignore, paths: &[PathBuf]) -> Vec<PathBuf> {
+    let ignore_root = ignore
+        .path()
+        .canonicalize()
+        .expect("ignore root canonicalize error");
+
+    paths
+        .iter()
+        .filter(|path| {
+            let relative_path = pathdiff::diff_paths(&path, &ignore_root)
+                .expect("One of the paths should be an absolute");
+            !ignore
+                .matched_path_or_any_parents(&relative_path, relative_path.is_dir())
+                .is_ignore()
+        })
+        .map(|path| path.to_path_buf())
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ignore::gitignore::GitignoreBuilder;
+    use std::env;
+
+    #[test]
+    fn test_filter_ignored_files() {
+        let current_dir = env::current_dir().unwrap();
+
+        let ignore = GitignoreBuilder::new(&current_dir)
+            .add_line(None, "*.html")
+            .unwrap()
+            .build()
+            .unwrap();
+        let should_remain = current_dir.join("record.text");
+        let should_filter = current_dir.join("index.html");
+
+        let remain = filter_ignored_files(ignore, &[should_remain.clone(), should_filter]);
+        assert_eq!(remain, vec![should_remain])
+    }
+
+    #[test]
+    fn filter_ignored_files_should_handle_parent_dir() {
+        let current_dir = env::current_dir().unwrap();
+
+        let ignore = GitignoreBuilder::new(&current_dir)
+            .add_line(None, "*.html")
+            .unwrap()
+            .build()
+            .unwrap();
+
+        let parent_dir = current_dir.join("..");
+        let should_remain = parent_dir.join("record.text");
+        let should_filter = parent_dir.join("index.html");
+
+        let remain = filter_ignored_files(ignore, &[should_remain.clone(), should_filter]);
+        assert_eq!(remain, vec![should_remain])
+    }
+}
--- a/src/cmd/watch/poller.rs
+++ b/src/cmd/watch/poller.rs
@@ -0,0 +1,386 @@
+//! A simple poll-based filesystem watcher.
+//!
+//! This exists because the native change notifications have historically had
+//! lots of problems. Various operating systems and different filesystems have
+//! had problems correctly reporting changes.
+
+use ignore::gitignore::Gitignore;
+use mdbook::MDBook;
+use pathdiff::diff_paths;
+use std::collections::HashMap;
+use std::fs::FileType;
+use std::path::{Path, PathBuf};
+use std::time::{Duration, Instant, SystemTime};
+use walkdir::WalkDir;
+
+/// Calls the closure when a book source file is changed, blocking indefinitely.
+pub fn rebuild_on_change(
+    book_dir: &Path,
+    update_config: &dyn Fn(&mut MDBook),
+    post_build: &dyn Fn(),
+) {
+    let mut book = MDBook::load(book_dir).unwrap_or_else(|e| {
+        error!("failed to load book: {e}");
+        std::process::exit(1);
+    });
+
+    let mut watcher = Watcher::new(book_dir);
+
+    info!("Watching for changes...");
+    // Scan once to initialize the starting point.
+    watcher.set_roots(&book);
+    watcher.scan();
+
+    // Track average scan time, to help investigate if the poller is taking
+    // undesirably long. This is not a rigorous benchmark, just a rough
+    // estimate.
+    const AVG_SIZE: usize = 60;
+    let mut avgs = vec![0.0; AVG_SIZE];
+    let mut avg_i = 0;
+
+    loop {
+        std::thread::sleep(Duration::new(1, 0));
+        watcher.set_roots(&book);
+        let start = Instant::now();
+        let paths = watcher.scan();
+        let elapsed = start.elapsed().as_secs_f64();
+        avgs[avg_i] = elapsed;
+        avg_i += 1;
+        if avg_i >= AVG_SIZE {
+            avg_i = 0;
+            let avg = avgs.iter().sum::<f64>() / (avgs.len() as f64);
+            trace!(
+                "scan average time: {avg:.2}s, scan size is {}",
+                watcher.path_data.len()
+            );
+        }
+
+        if !paths.is_empty() {
+            info!("Files changed: {paths:?}");
+            match MDBook::load(book_dir) {
+                Ok(mut b) => {
+                    update_config(&mut b);
+                    if let Err(e) = b.build() {
+                        error!("failed to build the book: {e:?}");
+                    } else {
+                        post_build();
+                    }
+                    book = b;
+                }
+                Err(e) => error!("failed to load book config: {e:?}"),
+            }
+        }
+    }
+}
+
+#[derive(PartialEq)]
+struct PathData {
+    file_type: FileType,
+    mtime: SystemTime,
+    size: u64,
+}
+
+/// A very simple poll-watcher that scans for modified files.
+#[derive(Default)]
+struct Watcher {
+    /// The root paths where it will recursively scan for changes.
+    root_paths: Vec<PathBuf>,
+    /// Data about files on disk.
+    path_data: HashMap<PathBuf, PathData>,
+    /// Filters paths that will be watched.
+    ignore: Option<(PathBuf, Gitignore)>,
+}
+
+impl Watcher {
+    fn new(book_root: &Path) -> Watcher {
+        // FIXME: ignore should be reloaded when it changes.
+        let ignore = super::find_gitignore(book_root).map(|gitignore_path| {
+            let (ignore, err) = Gitignore::new(&gitignore_path);
+            if let Some(err) = err {
+                warn!(
+                    "error reading gitignore `{}`: {err}",
+                    gitignore_path.display()
+                );
+            }
+            // Note: The usage of `canonicalize` may encounter occasional
+            // failures on the Windows platform, presenting a potential risk.
+            // For more details, refer to [Pull Request
+            // #2229](https://github.com/rust-lang/mdBook/pull/2229#discussion_r1408665981).
+            let ignore_path = ignore
+                .path()
+                .canonicalize()
+                .expect("ignore root canonicalize error");
+            (ignore_path, ignore)
+        });
+
+        Watcher {
+            ignore,
+            ..Default::default()
+        }
+    }
+
+    /// Sets the root directories where scanning will start.
+    fn set_roots(&mut self, book: &MDBook) {
+        let mut root_paths = vec![
+            book.source_dir(),
+            book.theme_dir(),
+            book.root.join("book.toml"),
+        ];
+        root_paths.extend(
+            book.config
+                .build
+                .extra_watch_dirs
+                .iter()
+                .map(|path| book.root.join(path)),
+        );
+        if let Some(html_config) = book.config.html_config() {
+            root_paths.extend(
+                html_config
+                    .additional_css
+                    .iter()
+                    .chain(html_config.additional_js.iter())
+                    .map(|path| book.root.join(path)),
+            );
+        }
+
+        self.root_paths = root_paths;
+    }
+
+    /// Scans for changes.
+    ///
+    /// Returns the paths that have changed.
+    fn scan(&mut self) -> Vec<PathBuf> {
+        let ignore = &self.ignore;
+        let new_path_data: HashMap<_, _> = self
+            .root_paths
+            .iter()
+            .filter(|root| root.exists())
+            .flat_map(|root| {
+                WalkDir::new(root)
+                    .follow_links(true)
+                    .into_iter()
+                    .filter_entry(|entry| {
+                        if let Some((ignore_path, ignore)) = ignore {
+                            let path = entry.path();
+                            // Canonicalization helps with removing `..` and
+                            // `.` entries, which can cause issues with
+                            // diff_paths.
+                            let path = path.canonicalize().unwrap_or_else(|_| path.to_path_buf());
+                            let relative_path = diff_paths(&path, &ignore_path)
+                                .expect("One of the paths should be an absolute");
+                            if ignore
+                                .matched_path_or_any_parents(&relative_path, relative_path.is_dir())
+                                .is_ignore()
+                            {
+                                trace!("ignoring {path:?}");
+                                return false;
+                            }
+                        }
+                        true
+                    })
+                    .filter_map(move |entry| {
+                        let entry = match entry {
+                            Ok(e) => e,
+                            Err(e) => {
+                                debug!("failed to scan {root:?}: {e}");
+                                return None;
+                            }
+                        };
+                        if entry.file_type().is_dir() {
+                            // Changes to directories themselves aren't
+                            // particularly interesting.
+                            return None;
+                        }
+                        let path = entry.path().to_path_buf();
+
+                        let meta = match entry.metadata() {
+                            Ok(meta) => meta,
+                            Err(e) => {
+                                debug!("failed to scan {path:?}: {e}");
+                                return None;
+                            }
+                        };
+                        let mtime = meta.modified().unwrap_or(SystemTime::UNIX_EPOCH);
+                        let pd = PathData {
+                            file_type: meta.file_type(),
+                            mtime,
+                            size: meta.len(),
+                        };
+                        Some((path, pd))
+                    })
+            })
+            .collect();
+        let mut paths = Vec::new();
+        for (new_path, new_data) in &new_path_data {
+            match self.path_data.get(new_path) {
+                Some(old_data) => {
+                    if new_data != old_data {
+                        paths.push(new_path.to_path_buf());
+                    }
+                }
+                None => {
+                    paths.push(new_path.clone());
+                }
+            }
+        }
+        for old_path in self.path_data.keys() {
+            if !new_path_data.contains_key(old_path) {
+                paths.push(old_path.to_path_buf());
+            }
+        }
+        self.path_data = new_path_data;
+        paths
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// Helper for testing the watcher.
+    fn check_watch_behavior(
+        gitignore_path: &str,
+        gitignore: &str,
+        book_root_path: &str,
+        ignored: &[&str],
+        not_ignored: &[&str],
+        extra_setup: &dyn Fn(&Path),
+    ) {
+        // Create the book and initialize things.
+        let temp = tempfile::Builder::new()
+            .prefix("mdbook-")
+            .tempdir()
+            .unwrap();
+        let root = temp.path();
+        let book_root = root.join(book_root_path);
+        // eprintln!("book_root={book_root:?}",);
+        MDBook::init(&book_root).build().unwrap();
+        std::fs::write(root.join(gitignore_path), gitignore).unwrap();
+        let create = |paths: &[&str]| {
+            let mut paths = paths
+                .iter()
+                .map(|path| root.join(path))
+                .inspect(|path| {
+                    std::fs::create_dir_all(path.parent().unwrap()).unwrap();
+                    std::fs::write(path, "initial content").unwrap();
+                })
+                .map(|path| path.canonicalize().unwrap())
+                .collect::<Vec<_>>();
+            paths.sort();
+            paths
+        };
+        let ignored = create(ignored);
+        let not_ignored = create(not_ignored);
+        extra_setup(&book_root);
+        // Create a watcher and check its behavior.
+        let book = MDBook::load(&book_root).unwrap();
+        let mut watcher = Watcher::new(&book_root);
+        watcher.set_roots(&book);
+        // Do an initial scan to initialize its state.
+        watcher.scan();
+        // Verify the steady state is empty.
+        let changed = watcher.scan();
+        assert_eq!(changed, Vec::<PathBuf>::new());
+        // Modify all files, and verify that only not_ignored are detected.
+        for path in ignored.iter().chain(not_ignored.iter()) {
+            std::fs::write(path, "modified").unwrap();
+        }
+        let changed = watcher.scan();
+        let mut changed = changed
+            .into_iter()
+            .map(|p| p.canonicalize().unwrap())
+            .collect::<Vec<_>>();
+        changed.sort();
+        assert_eq!(changed, not_ignored);
+        // Verify again that steady state is empty.
+        let changed = watcher.scan();
+        assert_eq!(changed, Vec::<PathBuf>::new());
+    }
+
+    #[test]
+    fn test_ignore() {
+        // Basic gitignore test.
+        check_watch_behavior(
+            "foo/.gitignore",
+            "*.tmp",
+            "foo",
+            &["foo/src/somefile.tmp"],
+            &["foo/src/chapter.md"],
+            &|_book_root| {},
+        );
+    }
+
+    #[test]
+    fn test_ignore_in_parent() {
+        // gitignore is in the parent of the book
+        check_watch_behavior(
+            ".gitignore",
+            "*.tmp\nsomedir/\n/inroot\n/foo/src/inbook\n",
+            "foo",
+            &[
+                "foo/src/somefile.tmp",
+                "foo/src/somedir/somefile",
+                "inroot/somefile",
+                "foo/src/inbook/somefile",
+            ],
+            &["foo/src/inroot/somefile"],
+            &|_book_root| {},
+        );
+    }
+
+    #[test]
+    fn test_ignore_canonical() {
+        // test with path with ..
+        check_watch_behavior(
+            ".gitignore",
+            "*.tmp\nsomedir/\n/foo/src/inbook\n",
+            "bar/../foo",
+            &[
+                "foo/src/somefile.tmp",
+                "foo/src/somedir/somefile",
+                "foo/src/inbook/somefile",
+            ],
+            &["foo/src/chapter.md"],
+            &|_book_root| {},
+        );
+    }
+
+    #[test]
+    fn test_scan_extra_watch() {
+        // Check behavior with extra-watch-dirs
+        check_watch_behavior(
+            ".gitignore",
+            "*.tmp\n/outside-root/ignoreme\n/foo/examples/ignoreme\n",
+            "foo",
+            &[
+                "foo/src/somefile.tmp",
+                "foo/examples/example.tmp",
+                "outside-root/somefile.tmp",
+                "outside-root/ignoreme",
+                "foo/examples/ignoreme",
+            ],
+            &[
+                "foo/src/chapter.md",
+                "foo/examples/example.rs",
+                "foo/examples/example2.rs",
+                "outside-root/image.png",
+            ],
+            &|book_root| {
+                std::fs::write(
+                    book_root.join("book.toml"),
+                    r#"
+                        [book]
+                        title = "foo"
+
+                        [build]
+                        extra-watch-dirs = [
+                            "examples",
+                            "../outside-root",
+                        ]
+                    "#,
+                )
+                .unwrap();
+            },
+        );
+    }
+}
--- a/src/config.rs
+++ b/src/config.rs
@@ -58,7 +58,7 @@ use std::io::Read;
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use toml::value::Table;
-use toml::{self, Value};
+use toml::Value;

 use crate::errors::*;
 use crate::utils::{self, toml_ext::TomlExt};
@@ -145,7 +145,7 @@ impl Config {
                if let serde_json::Value::Object(ref map) = parsed_value {
                    // To `set` each `key`, we wrap them as `prefix.key`
                    for (k, v) in map {
-                        let full_key = format!("{}.{}", key, k);
+                        let full_key = format!("{key}.{k}");
                        self.set(&full_key, v).expect("unreachable");
                    }
                    return;
@@ -411,6 +411,9 @@ pub struct BookConfig {
    pub multilingual: bool,
    /// The main language of the book.
    pub language: Option<String>,
+    /// The direction of text in the book: Left-to-right (LTR) or Right-to-left (RTL).
+    /// When not specified, the text direction is derived from [`BookConfig::language`].
+    pub text_direction: Option<TextDirection>,
 }

 impl Default for BookConfig {
@@ -422,6 +425,43 @@ impl Default for BookConfig {
            src: PathBuf::from("src"),
            multilingual: false,
            language: Some(String::from("en")),
+            text_direction: None,
+        }
+    }
+}
+
+impl BookConfig {
+    /// Gets the realized text direction, either from [`BookConfig::text_direction`]
+    /// or derived from [`BookConfig::language`], to be used by templating engines.
+    pub fn realized_text_direction(&self) -> TextDirection {
+        if let Some(direction) = self.text_direction {
+            direction
+        } else {
+            TextDirection::from_lang_code(self.language.as_deref().unwrap_or_default())
+        }
+    }
+}
+
+/// Text direction to use for HTML output
+#[derive(Debug, Copy, Clone, PartialEq, Serialize, Deserialize)]
+pub enum TextDirection {
+    /// Left to right.
+    #[serde(rename = "ltr")]
+    LeftToRight,
+    /// Right to left
+    #[serde(rename = "rtl")]
+    RightToLeft,
+}
+
+impl TextDirection {
+    /// Gets the text direction from language code
+    pub fn from_lang_code(code: &str) -> Self {
+        match code {
+            // list sourced from here: https://github.com/abarrak/rtl/blob/master/lib/rtl/core.rb#L16
+            "ar" | "ara" | "arc" | "ae" | "ave" | "egy" | "he" | "heb" | "nqo" | "pal" | "phn"
+            | "sam" | "syc" | "syr" | "fa" | "per" | "fas" | "ku" | "kur" | "ur" | "urd"
+            | "pus" | "ps" | "yi" | "yid" => TextDirection::RightToLeft,
+            _ => TextDirection::LeftToRight,
        }
    }
 }
@@ -464,6 +504,9 @@ pub struct RustConfig {
 #[derive(Debug, Copy, Clone, PartialEq, Serialize, Deserialize)]
 /// Rust edition to use for the code.
 pub enum RustEdition {
+    /// The 2024 edition of Rust
+    #[serde(rename = "2024")]
+    E2024,
    /// The 2021 edition of Rust
    #[serde(rename = "2021")]
    E2021,
@@ -486,7 +529,9 @@ pub struct HtmlConfig {
    /// The theme to use if the browser requests the dark version of the site.
    /// Defaults to 'navy'.
    pub preferred_dark_theme: Option<String>,
-    /// Use "smart quotes" instead of the usual `"` character.
+    /// Supports smart quotes, apostrophes, ellipsis, en-dash, and em-dash.
+    pub smart_punctuation: bool,
+    /// Deprecated alias for `smart_punctuation`.
    pub curly_quotes: bool,
    /// Should mathjax be enabled?
    pub mathjax_support: bool,
@@ -550,6 +595,7 @@ impl Default for HtmlConfig {
            theme: None,
            default_theme: None,
            preferred_dark_theme: None,
+            smart_punctuation: false,
            curly_quotes: false,
            mathjax_support: false,
            copy_fonts: true,
@@ -583,6 +629,11 @@ impl HtmlConfig {
            None => root.join("theme"),
        }
    }
+
+    /// Returns `true` if smart punctuation is enabled.
+    pub fn smart_punctuation(&self) -> bool {
+        self.smart_punctuation || self.curly_quotes
+    }
 }

 /// Configuration for how to render the print icon, print.html, and print.css.
@@ -616,7 +667,7 @@ pub struct Fold {
    pub level: u8,
 }

-/// Configuration for tweaking how the the HTML renderer handles the playground.
+/// Configuration for tweaking how the HTML renderer handles the playground.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(default, rename_all = "kebab-case")]
 pub struct Playground {
@@ -645,22 +696,14 @@ impl Default for Playground {
    }
 }

-/// Configuration for tweaking how the the HTML renderer handles code blocks.
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+/// Configuration for tweaking how the HTML renderer handles code blocks.
+#[derive(Debug, Default, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(default, rename_all = "kebab-case")]
 pub struct Code {
    /// A prefix string to hide lines per language (one or more chars).
    pub hidelines: HashMap<String, String>,
 }

-impl Default for Code {
-    fn default() -> Code {
-        Code {
-            hidelines: HashMap::new(),
-        }
-    }
-}
-
 /// Configuration of the search functionality of the HTML renderer.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(default, rename_all = "kebab-case")]
@@ -692,6 +735,11 @@ pub struct Search {
    /// Copy JavaScript files for the search functionality to the output directory?
    /// Default: `true`.
    pub copy_js: bool,
+    /// Specifies search settings for the given path.
+    ///
+    /// The path can be for a specific chapter, or a directory. This will
+    /// merge recursively, with more specific paths taking precedence.
+    pub chapter: HashMap<String, SearchChapterSettings>,
 }

 impl Default for Search {
@@ -708,10 +756,19 @@ impl Default for Search {
            expand: true,
            heading_split_level: 3,
            copy_js: true,
+            chapter: HashMap::new(),
        }
    }
 }

+/// Search options for chapters (or paths).
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, Default)]
+#[serde(default, rename_all = "kebab-case")]
+pub struct SearchChapterSettings {
+    /// Whether or not indexing is enabled, default `true`.
+    pub enable: Option<bool>,
+}
+
 /// Allows you to "update" any arbitrary field in a struct by round-tripping via
 /// a `toml::Value`.
 ///
@@ -758,7 +815,7 @@ mod tests {
        [output.html]
        theme = "./themedir"
        default-theme = "rust"
-        curly-quotes = true
+        smart-punctuation = true
        google-analytics = "123456"
        additional-css = ["./foo/bar/baz.css"]
        git-repository-url = "https://foo.com/"
@@ -788,6 +845,7 @@ mod tests {
            multilingual: true,
            src: PathBuf::from("source"),
            language: Some(String::from("ja")),
+            text_direction: None,
        };
        let build_should_be = BuildConfig {
            build_dir: PathBuf::from("outputs"),
@@ -804,7 +862,7 @@ mod tests {
            runnable: true,
        };
        let html_should_be = HtmlConfig {
-            curly_quotes: true,
+            smart_punctuation: true,
            google_analytics: Some(String::from("123456")),
            additional_css: vec![PathBuf::from("./foo/bar/baz.css")],
            theme: Some(PathBuf::from("./themedir")),
@@ -984,7 +1042,7 @@ mod tests {
        [output.html]
        destination = "my-book" # the output files will be generated in `root/my-book` instead of `root/book`
        theme = "my-theme"
-        curly-quotes = true
+        smart-punctuation = true
        google-analytics = "123456"
        additional-css = ["custom.css", "custom2.css"]
        additional-js = ["custom.js"]
@@ -1009,7 +1067,7 @@ mod tests {

        let html_should_be = HtmlConfig {
            theme: Some(PathBuf::from("my-theme")),
-            curly_quotes: true,
+            smart_punctuation: true,
            google_analytics: Some(String::from("123456")),
            additional_css: vec![PathBuf::from("custom.css"), PathBuf::from("custom2.css")],
            additional_js: vec![PathBuf::from("custom.js")],
@@ -1140,6 +1198,73 @@ mod tests {
        assert_eq!(&get_404_output_file(&html_config.input_404), "missing.html");
    }

+    #[test]
+    fn text_direction_ltr() {
+        let src = r#"
+        [book]
+        text-direction = "ltr"
+        "#;
+
+        let got = Config::from_str(src).unwrap();
+        assert_eq!(got.book.text_direction, Some(TextDirection::LeftToRight));
+    }
+
+    #[test]
+    fn text_direction_rtl() {
+        let src = r#"
+        [book]
+        text-direction = "rtl"
+        "#;
+
+        let got = Config::from_str(src).unwrap();
+        assert_eq!(got.book.text_direction, Some(TextDirection::RightToLeft));
+    }
+
+    #[test]
+    fn text_direction_none() {
+        let src = r#"
+        [book]
+        "#;
+
+        let got = Config::from_str(src).unwrap();
+        assert_eq!(got.book.text_direction, None);
+    }
+
+    #[test]
+    fn test_text_direction() {
+        let mut cfg = BookConfig::default();
+
+        // test deriving the text direction from language codes
+        cfg.language = Some("ar".into());
+        assert_eq!(cfg.realized_text_direction(), TextDirection::RightToLeft);
+
+        cfg.language = Some("he".into());
+        assert_eq!(cfg.realized_text_direction(), TextDirection::RightToLeft);
+
+        cfg.language = Some("en".into());
+        assert_eq!(cfg.realized_text_direction(), TextDirection::LeftToRight);
+
+        cfg.language = Some("ja".into());
+        assert_eq!(cfg.realized_text_direction(), TextDirection::LeftToRight);
+
+        // test forced direction
+        cfg.language = Some("ar".into());
+        cfg.text_direction = Some(TextDirection::LeftToRight);
+        assert_eq!(cfg.realized_text_direction(), TextDirection::LeftToRight);
+
+        cfg.language = Some("ar".into());
+        cfg.text_direction = Some(TextDirection::RightToLeft);
+        assert_eq!(cfg.realized_text_direction(), TextDirection::RightToLeft);
+
+        cfg.language = Some("en".into());
+        cfg.text_direction = Some(TextDirection::LeftToRight);
+        assert_eq!(cfg.realized_text_direction(), TextDirection::LeftToRight);
+
+        cfg.language = Some("en".into());
+        cfg.text_direction = Some(TextDirection::RightToLeft);
+        assert_eq!(cfg.realized_text_direction(), TextDirection::RightToLeft);
+    }
+
    #[test]
    #[should_panic(expected = "Invalid configuration file")]
    fn invalid_language_type_error() {
@@ -1212,4 +1337,37 @@ mod tests {
        assert!(html_config.print.enable);
        assert!(!html_config.print.page_break);
    }
+
+    #[test]
+    fn curly_quotes_or_smart_punctuation() {
+        let src = r#"
+        [book]
+        title = "mdBook Documentation"
+
+        [output.html]
+        smart-punctuation = true
+        "#;
+        let config = Config::from_str(src).unwrap();
+        assert_eq!(config.html_config().unwrap().smart_punctuation(), true);
+
+        let src = r#"
+        [book]
+        title = "mdBook Documentation"
+
+        [output.html]
+        curly-quotes = true
+        "#;
+        let config = Config::from_str(src).unwrap();
+        assert_eq!(config.html_config().unwrap().smart_punctuation(), true);
+
+        let src = r#"
+        [book]
+        title = "mdBook Documentation"
+        "#;
+        let config = Config::from_str(src).unwrap();
+        assert_eq!(
+            config.html_config().unwrap_or_default().smart_punctuation(),
+            false
+        );
+    }
 }
--- a/src/preprocess/links.rs
+++ b/src/preprocess/links.rs
@@ -493,7 +493,7 @@ mod tests {
        let s = "Some random text with {{#playground file.rs}} and {{#playground test.rs }}...";

        let res = find_links(s).collect::<Vec<_>>();
-        println!("\nOUTPUT: {:?}\n", res);
+        println!("\nOUTPUT: {res:?}\n");

        assert_eq!(
            res,
@@ -519,7 +519,7 @@ mod tests {
        let s = "Some random text with {{#playground foo-bar\\baz/_c++.rs}}...";

        let res = find_links(s).collect::<Vec<_>>();
-        println!("\nOUTPUT: {:?}\n", res);
+        println!("\nOUTPUT: {res:?}\n");

        assert_eq!(
            res,
@@ -536,7 +536,7 @@ mod tests {
    fn test_find_links_with_range() {
        let s = "Some random text with {{#include file.rs:10:20}}...";
        let res = find_links(s).collect::<Vec<_>>();
-        println!("\nOUTPUT: {:?}\n", res);
+        println!("\nOUTPUT: {res:?}\n");
        assert_eq!(
            res,
            vec![Link {
@@ -555,7 +555,7 @@ mod tests {
    fn test_find_links_with_line_number() {
        let s = "Some random text with {{#include file.rs:10}}...";
        let res = find_links(s).collect::<Vec<_>>();
-        println!("\nOUTPUT: {:?}\n", res);
+        println!("\nOUTPUT: {res:?}\n");
        assert_eq!(
            res,
            vec![Link {
@@ -574,7 +574,7 @@ mod tests {
    fn test_find_links_with_from_range() {
        let s = "Some random text with {{#include file.rs:10:}}...";
        let res = find_links(s).collect::<Vec<_>>();
-        println!("\nOUTPUT: {:?}\n", res);
+        println!("\nOUTPUT: {res:?}\n");
        assert_eq!(
            res,
            vec![Link {
@@ -593,7 +593,7 @@ mod tests {
    fn test_find_links_with_to_range() {
        let s = "Some random text with {{#include file.rs::20}}...";
        let res = find_links(s).collect::<Vec<_>>();
-        println!("\nOUTPUT: {:?}\n", res);
+        println!("\nOUTPUT: {res:?}\n");
        assert_eq!(
            res,
            vec![Link {
@@ -612,7 +612,7 @@ mod tests {
    fn test_find_links_with_full_range() {
        let s = "Some random text with {{#include file.rs::}}...";
        let res = find_links(s).collect::<Vec<_>>();
-        println!("\nOUTPUT: {:?}\n", res);
+        println!("\nOUTPUT: {res:?}\n");
        assert_eq!(
            res,
            vec![Link {
@@ -631,7 +631,7 @@ mod tests {
    fn test_find_links_with_no_range_specified() {
        let s = "Some random text with {{#include file.rs}}...";
        let res = find_links(s).collect::<Vec<_>>();
-        println!("\nOUTPUT: {:?}\n", res);
+        println!("\nOUTPUT: {res:?}\n");
        assert_eq!(
            res,
            vec![Link {
@@ -650,7 +650,7 @@ mod tests {
    fn test_find_links_with_anchor() {
        let s = "Some random text with {{#include file.rs:anchor}}...";
        let res = find_links(s).collect::<Vec<_>>();
-        println!("\nOUTPUT: {:?}\n", res);
+        println!("\nOUTPUT: {res:?}\n");
        assert_eq!(
            res,
            vec![Link {
@@ -670,7 +670,7 @@ mod tests {
        let s = "Some random text with escaped playground \\{{#playground file.rs editable}} ...";

        let res = find_links(s).collect::<Vec<_>>();
-        println!("\nOUTPUT: {:?}\n", res);
+        println!("\nOUTPUT: {res:?}\n");

        assert_eq!(
            res,
@@ -690,7 +690,7 @@ mod tests {
                 more\n text {{#playground my.rs editable no_run should_panic}} ...";

        let res = find_links(s).collect::<Vec<_>>();
-        println!("\nOUTPUT: {:?}\n", res);
+        println!("\nOUTPUT: {res:?}\n");
        assert_eq!(
            res,
            vec![
@@ -721,7 +721,7 @@ mod tests {
                 no_run should_panic}} ...";

        let res = find_links(s).collect::<Vec<_>>();
-        println!("\nOUTPUT: {:?}\n", res);
+        println!("\nOUTPUT: {res:?}\n");
        assert_eq!(res.len(), 3);
        assert_eq!(
            res[0],
--- a/src/renderer/html_handlebars/hbs_renderer.rs
+++ b/src/renderer/html_handlebars/hbs_renderer.rs
@@ -54,11 +54,13 @@ impl HtmlHandlebars {
                .insert("git_repository_edit_url".to_owned(), json!(edit_url));
        }

-        let content = ch.content.clone();
-        let content = utils::render_markdown(&content, ctx.html_config.curly_quotes);
+        let content = utils::render_markdown(&ch.content, ctx.html_config.smart_punctuation());

-        let fixed_content =
-            utils::render_markdown_with_path(&ch.content, ctx.html_config.curly_quotes, Some(path));
+        let fixed_content = utils::render_markdown_with_path(
+            &ch.content,
+            ctx.html_config.smart_punctuation(),
+            Some(path),
+        );
        if !ctx.is_index && ctx.html_config.print.page_break {
            // Add page break between chapters
            // See https://developer.mozilla.org/en-US/docs/Web/CSS/break-before and https://developer.mozilla.org/en-US/docs/Web/CSS/page-break-before
@@ -151,13 +153,13 @@ impl HtmlHandlebars {
        let content_404 = if let Some(ref filename) = html_config.input_404 {
            let path = src_dir.join(filename);
            std::fs::read_to_string(&path)
-                .with_context(|| format!("unable to open 404 input file {:?}", path))?
+                .with_context(|| format!("unable to open 404 input file {path:?}"))?
        } else {
            // 404 input not explicitly configured try the default file 404.md
            let default_404_location = src_dir.join("404.md");
            if default_404_location.exists() {
                std::fs::read_to_string(&default_404_location).with_context(|| {
-                    format!("unable to open 404 input file {:?}", default_404_location)
+                    format!("unable to open 404 input file {default_404_location:?}")
                })?
            } else {
                "# Document not found (404)\n\nThis URL is invalid, sorry. Please use the \
@@ -165,7 +167,8 @@ impl HtmlHandlebars {
                    .to_string()
            }
        };
-        let html_content_404 = utils::render_markdown(&content_404, html_config.curly_quotes);
+        let html_content_404 =
+            utils::render_markdown(&content_404, html_config.smart_punctuation());

        let mut data_404 = data.clone();
        let base_url = if let Some(site_url) = &html_config.site_url {
@@ -203,7 +206,7 @@ impl HtmlHandlebars {
        Ok(())
    }

-    #[cfg_attr(feature = "cargo-clippy", allow(clippy::let_and_return))]
+    #[allow(clippy::let_and_return)]
    fn post_process(
        &self,
        rendered: String,
@@ -234,7 +237,7 @@ impl HtmlHandlebars {
        )?;

        if let Some(cname) = &html_config.cname {
-            write_file(destination, "CNAME", format!("{}\n", cname).as_bytes())?;
+            write_file(destination, "CNAME", format!("{cname}\n").as_bytes())?;
        }

        write_file(destination, "book.js", &theme.js)?;
@@ -478,25 +481,6 @@ impl HtmlHandlebars {
    }
 }

-// TODO(mattico): Remove some time after the 0.1.8 release
-fn maybe_wrong_theme_dir(dir: &Path) -> Result<bool> {
-    fn entry_is_maybe_book_file(entry: fs::DirEntry) -> Result<bool> {
-        Ok(entry.file_type()?.is_file()
-            && entry.path().extension().map_or(false, |ext| ext == "md"))
-    }
-
-    if dir.is_dir() {
-        for entry in fs::read_dir(dir)? {
-            if entry_is_maybe_book_file(entry?).unwrap_or(false) {
-                return Ok(false);
-            }
-        }
-        Ok(true)
-    } else {
-        Ok(false)
-    }
-}
-
 impl Renderer for HtmlHandlebars {
    fn name(&self) -> &str {
        "html"
@@ -529,16 +513,6 @@ impl Renderer for HtmlHandlebars {
            None => ctx.root.join("theme"),
        };

-        if html_config.theme.is_none()
-            && maybe_wrong_theme_dir(&src_dir.join("theme")).unwrap_or(false)
-        {
-            warn!(
-                "Previous versions of mdBook erroneously accepted `./src/theme` as an automatic \
-                 theme directory"
-            );
-            warn!("Please move your theme files to `./theme` for them to continue being used");
-        }
-
        let theme = theme::Theme::new(theme_dir);

        debug!("Register the index handlebars template");
@@ -554,6 +528,11 @@ impl Renderer for HtmlHandlebars {
        debug!("Register the header handlebars template");
        handlebars.register_partial("header", String::from_utf8(theme.header.clone())?)?;

+        debug!("Register the toc handlebars template");
+        handlebars.register_template_string("toc_js", String::from_utf8(theme.toc_js.clone())?)?;
+        handlebars
+            .register_template_string("toc_html", String::from_utf8(theme.toc_html.clone())?)?;
+
        debug!("Register handlebars helpers");
        self.register_hbs_helpers(&mut handlebars, &html_config);

@@ -609,6 +588,18 @@ impl Renderer for HtmlHandlebars {
            debug!("Creating print.html ✓");
        }

+        debug!("Render toc");
+        {
+            let rendered_toc = handlebars.render("toc_js", &data)?;
+            utils::fs::write_file(destination, "toc.js", rendered_toc.as_bytes())?;
+            debug!("Creating toc.js ✓");
+            data.insert("is_toc_html".to_owned(), json!(true));
+            let rendered_toc = handlebars.render("toc_html", &data)?;
+            utils::fs::write_file(destination, "toc.html", rendered_toc.as_bytes())?;
+            debug!("Creating toc.html ✓");
+            data.remove("is_toc_html");
+        }
+
        debug!("Copy static files");
        self.copy_static_files(destination, &theme, &html_config)
            .with_context(|| "Unable to copy across static files")?;
@@ -648,6 +639,10 @@ fn make_data(
        "language".to_owned(),
        json!(config.book.language.clone().unwrap_or_default()),
    );
+    data.insert(
+        "text_direction".to_owned(),
+        json!(config.book.realized_text_direction()),
+    );
    data.insert(
        "book_title".to_owned(),
        json!(config.book.title.clone().unwrap_or_default()),
@@ -856,11 +851,7 @@ fn insert_link_into_header(
        .unwrap_or_default();

    format!(
-        r##"<h{level} id="{id}"{classes}><a class="header" href="#{id}">{text}</a></h{level}>"##,
-        level = level,
-        id = id,
-        text = content,
-        classes = classes
+        r##"<h{level} id="{id}"{classes}><a class="header" href="#{id}">{content}</a></h{level}>"##
    )
 }

@@ -882,12 +873,7 @@ fn fix_code_blocks(html: &str) -> String {
            let classes = &caps[2].replace(',', " ");
            let after = &caps[3];

-            format!(
-                r#"<code{before}class="{classes}"{after}>"#,
-                before = before,
-                classes = classes,
-                after = after
-            )
+            format!(r#"<code{before}class="{classes}"{after}>"#)
        })
        .into_owned()
 }
@@ -924,6 +910,7 @@ fn add_playground_pre(
                        Some(RustEdition::E2015) => " edition2015",
                        Some(RustEdition::E2018) => " edition2018",
                        Some(RustEdition::E2021) => " edition2021",
+                        Some(RustEdition::E2024) => " edition2024",
                        None => "",
                    }
                };
@@ -944,8 +931,7 @@ fn add_playground_pre(
                            // we need to inject our own main
                            let (attrs, code) = partition_source(code);

-                            format!("# #![allow(unused)]\n{}#fn main() {{\n{}#}}", attrs, code)
-                                .into()
+                            format!("# #![allow(unused)]\n{attrs}# fn main() {{\n{code}# }}").into()
                        };
                        content
                    }
@@ -961,8 +947,9 @@ fn add_playground_pre(
 /// Modifies all `<code>` blocks to convert "hidden" lines and to wrap them in
 /// a `<span class="boring">`.
 fn hide_lines(html: &str, code_config: &Code) -> String {
-    let language_regex = Regex::new(r"\blanguage-(\w+)\b").unwrap();
-    let hidelines_regex = Regex::new(r"\bhidelines=(\S+)").unwrap();
+    static LANGUAGE_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"\blanguage-(\w+)\b").unwrap());
+    static HIDELINES_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"\bhidelines=(\S+)").unwrap());
+
    CODE_BLOCK_RE
        .replace_all(html, |caps: &Captures<'_>| {
            let text = &caps[1];
@@ -977,12 +964,12 @@ fn hide_lines(html: &str, code_config: &Code) -> String {
                )
            } else {
                // First try to get the prefix from the code block
-                let hidelines_capture = hidelines_regex.captures(classes);
+                let hidelines_capture = HIDELINES_REGEX.captures(classes);
                let hidelines_prefix = match &hidelines_capture {
                    Some(capture) => Some(&capture[1]),
                    None => {
                        // Then look up the prefix by language
-                        language_regex.captures(classes).and_then(|capture| {
+                        LANGUAGE_REGEX.captures(classes).and_then(|capture| {
                            code_config.hidelines.get(&capture[1]).map(|p| p.as_str())
                        })
                    }
@@ -1016,12 +1003,9 @@ fn hide_lines_rust(content: &str) -> String {
                result += &caps[3];
                result += newline;
                continue;
-            } else if &caps[2] != "!" && &caps[2] != "[" {
+            } else if matches!(&caps[2], "" | " ") {
                result += "<span class=\"boring\">";
                result += &caps[1];
-                if &caps[2] != " " {
-                    result += &caps[2];
-                }
                result += &caps[3];
                result += newline;
                result += "</span>";
@@ -1088,6 +1072,8 @@ struct RenderItemContext<'a> {

 #[cfg(test)]
 mod tests {
+    use crate::config::TextDirection;
+
    use super::*;
    use pretty_assertions::assert_eq;

@@ -1145,7 +1131,7 @@ mod tests {
    fn add_playground() {
        let inputs = [
          ("<code class=\"language-rust\">x()</code>",
-           "<pre class=\"playground\"><code class=\"language-rust\"># #![allow(unused)]\n#fn main() {\nx()\n#}</code></pre>"),
+           "<pre class=\"playground\"><code class=\"language-rust\"># #![allow(unused)]\n# fn main() {\nx()\n# }</code></pre>"),
          ("<code class=\"language-rust\">fn main() {}</code>",
           "<pre class=\"playground\"><code class=\"language-rust\">fn main() {}</code></pre>"),
          ("<code class=\"language-rust editable\">let s = \"foo\n # bar\n\";</code>",
@@ -1175,7 +1161,7 @@ mod tests {
    fn add_playground_edition2015() {
        let inputs = [
          ("<code class=\"language-rust\">x()</code>",
-           "<pre class=\"playground\"><code class=\"language-rust edition2015\"># #![allow(unused)]\n#fn main() {\nx()\n#}</code></pre>"),
+           "<pre class=\"playground\"><code class=\"language-rust edition2015\"># #![allow(unused)]\n# fn main() {\nx()\n# }</code></pre>"),
          ("<code class=\"language-rust\">fn main() {}</code>",
           "<pre class=\"playground\"><code class=\"language-rust edition2015\">fn main() {}</code></pre>"),
          ("<code class=\"language-rust edition2015\">fn main() {}</code>",
@@ -1199,7 +1185,7 @@ mod tests {
    fn add_playground_edition2018() {
        let inputs = [
          ("<code class=\"language-rust\">x()</code>",
-           "<pre class=\"playground\"><code class=\"language-rust edition2018\"># #![allow(unused)]\n#fn main() {\nx()\n#}</code></pre>"),
+           "<pre class=\"playground\"><code class=\"language-rust edition2018\"># #![allow(unused)]\n# fn main() {\nx()\n# }</code></pre>"),
          ("<code class=\"language-rust\">fn main() {}</code>",
           "<pre class=\"playground\"><code class=\"language-rust edition2018\">fn main() {}</code></pre>"),
          ("<code class=\"language-rust edition2015\">fn main() {}</code>",
@@ -1223,7 +1209,7 @@ mod tests {
    fn add_playground_edition2021() {
        let inputs = [
            ("<code class=\"language-rust\">x()</code>",
-             "<pre class=\"playground\"><code class=\"language-rust edition2021\"># #![allow(unused)]\n#fn main() {\nx()\n#}</code></pre>"),
+             "<pre class=\"playground\"><code class=\"language-rust edition2021\"># #![allow(unused)]\n# fn main() {\nx()\n# }</code></pre>"),
            ("<code class=\"language-rust\">fn main() {}</code>",
             "<pre class=\"playground\"><code class=\"language-rust edition2021\">fn main() {}</code></pre>"),
            ("<code class=\"language-rust edition2015\">fn main() {}</code>",
@@ -1248,8 +1234,12 @@ mod tests {
    fn hide_lines_language_rust() {
        let inputs = [
          (
-           "<pre class=\"playground\"><code class=\"language-rust\">\n# #![allow(unused)]\n#fn main() {\nx()\n#}</code></pre>",
+           "<pre class=\"playground\"><code class=\"language-rust\">\n# #![allow(unused)]\n# fn main() {\nx()\n# }</code></pre>",
           "<pre class=\"playground\"><code class=\"language-rust\">\n<span class=\"boring\">#![allow(unused)]\n</span><span class=\"boring\">fn main() {\n</span>x()\n<span class=\"boring\">}</span></code></pre>",),
+          // # must be followed by a space for a line to be hidden
+          (
+           "<pre class=\"playground\"><code class=\"language-rust\">\n#fn main() {\nx()\n#}</code></pre>",
+           "<pre class=\"playground\"><code class=\"language-rust\">\n#fn main() {\nx()\n#}</code></pre>",),
          (
           "<pre class=\"playground\"><code class=\"language-rust\">fn main() {}</code></pre>",
           "<pre class=\"playground\"><code class=\"language-rust\">fn main() {}</code></pre>",),
@@ -1299,4 +1289,10 @@ mod tests {
            assert_eq!(&*got, *should_be);
        }
    }
+
+    #[test]
+    fn test_json_direction() {
+        assert_eq!(json!(TextDirection::RightToLeft), json!("rtl"));
+        assert_eq!(json!(TextDirection::LeftToRight), json!("ltr"));
+    }
 }
--- a/src/renderer/html_handlebars/helpers/navigation.rs
+++ b/src/renderer/html_handlebars/helpers/navigation.rs
@@ -1,7 +1,9 @@
 use std::collections::BTreeMap;
 use std::path::Path;

-use handlebars::{Context, Handlebars, Helper, Output, RenderContext, RenderError, Renderable};
+use handlebars::{
+    Context, Handlebars, Helper, Output, RenderContext, RenderError, RenderErrorReason, Renderable,
+};

 use crate::utils;
 use log::{debug, trace};
@@ -26,9 +28,9 @@ impl Target {
    ) -> Result<Option<StringMap>, RenderError> {
        match *self {
            Target::Next => {
-                let previous_path = previous_item
-                    .get("path")
-                    .ok_or_else(|| RenderError::new("No path found for chapter in JSON data"))?;
+                let previous_path = previous_item.get("path").ok_or_else(|| {
+                    RenderErrorReason::Other("No path found for chapter in JSON data".to_owned())
+                })?;

                if previous_path == base_path {
                    return Ok(Some(current_item.clone()));
@@ -54,15 +56,18 @@ fn find_chapter(
    debug!("Get data from context");

    let chapters = rc.evaluate(ctx, "@root/chapters").and_then(|c| {
-        serde_json::value::from_value::<Vec<StringMap>>(c.as_json().clone())
-            .map_err(|_| RenderError::new("Could not decode the JSON data"))
+        serde_json::value::from_value::<Vec<StringMap>>(c.as_json().clone()).map_err(|_| {
+            RenderErrorReason::Other("Could not decode the JSON data".to_owned()).into()
+        })
    })?;

    let base_path = rc
        .evaluate(ctx, "@root/path")?
        .as_json()
        .as_str()
-        .ok_or_else(|| RenderError::new("Type error for `path`, string expected"))?
+        .ok_or_else(|| {
+            RenderErrorReason::Other("Type error for `path`, string expected".to_owned())
+        })?
        .replace('\"', "");

    if !rc.evaluate(ctx, "@root/is_index")?.is_missing() {
@@ -98,7 +103,7 @@ fn find_chapter(
                    }
                }

-                previous = Some(item.clone());
+                previous = Some(item);
            }
            _ => continue,
        }
@@ -108,7 +113,7 @@ fn find_chapter(
 }

 fn render(
-    _h: &Helper<'_, '_>,
+    _h: &Helper<'_>,
    r: &Handlebars<'_>,
    ctx: &Context,
    rc: &mut RenderContext<'_, '_>,
@@ -122,7 +127,9 @@ fn render(
        .evaluate(ctx, "@root/path")?
        .as_json()
        .as_str()
-        .ok_or_else(|| RenderError::new("Type error for `path`, string expected"))?
+        .ok_or_else(|| {
+            RenderErrorReason::Other("Type error for `path`, string expected".to_owned())
+        })?
        .replace('\"', "");

    context.insert(
@@ -132,17 +139,23 @@ fn render(

    chapter
        .get("name")
-        .ok_or_else(|| RenderError::new("No title found for chapter in JSON data"))
+        .ok_or_else(|| {
+            RenderErrorReason::Other("No title found for chapter in JSON data".to_owned())
+        })
        .map(|name| context.insert("title".to_owned(), json!(name)))?;

    chapter
        .get("path")
-        .ok_or_else(|| RenderError::new("No path found for chapter in JSON data"))
+        .ok_or_else(|| {
+            RenderErrorReason::Other("No path found for chapter in JSON data".to_owned())
+        })
        .and_then(|p| {
            Path::new(p)
                .with_extension("html")
                .to_str()
-                .ok_or_else(|| RenderError::new("Link could not be converted to str"))
+                .ok_or_else(|| {
+                    RenderErrorReason::Other("Link could not be converted to str".to_owned())
+                })
                .map(|p| context.insert("link".to_owned(), json!(p.replace('\\', "/"))))
        })?;

@@ -150,14 +163,14 @@ fn render(

    let t = _h
        .template()
-        .ok_or_else(|| RenderError::new("Error with the handlebars template"))?;
+        .ok_or_else(|| RenderErrorReason::Other("Error with the handlebars template".to_owned()))?;
    let local_ctx = Context::wraps(&context)?;
    let mut local_rc = rc.clone();
    t.render(r, &local_ctx, &mut local_rc, out)
 }

 pub fn previous(
-    _h: &Helper<'_, '_>,
+    _h: &Helper<'_>,
    r: &Handlebars<'_>,
    ctx: &Context,
    rc: &mut RenderContext<'_, '_>,
@@ -173,7 +186,7 @@ pub fn previous(
 }

 pub fn next(
-    _h: &Helper<'_, '_>,
+    _h: &Helper<'_>,
    r: &Handlebars<'_>,
    ctx: &Context,
    rc: &mut RenderContext<'_, '_>,
--- a/src/renderer/html_handlebars/helpers/theme.rs
+++ b/src/renderer/html_handlebars/helpers/theme.rs
@@ -1,8 +1,10 @@
-use handlebars::{Context, Handlebars, Helper, Output, RenderContext, RenderError};
+use handlebars::{
+    Context, Handlebars, Helper, Output, RenderContext, RenderError, RenderErrorReason,
+};
 use log::trace;

 pub fn theme_option(
-    h: &Helper<'_, '_>,
+    h: &Helper<'_>,
    _r: &Handlebars<'_>,
    ctx: &Context,
    rc: &mut RenderContext<'_, '_>,
@@ -11,14 +13,21 @@ pub fn theme_option(
    trace!("theme_option (handlebars helper)");

    let param = h.param(0).and_then(|v| v.value().as_str()).ok_or_else(|| {
-        RenderError::new("Param 0 with String type is required for theme_option helper.")
+        RenderErrorReason::ParamTypeMismatchForName(
+            "theme_option",
+            "0".to_owned(),
+            "string".to_owned(),
+        )
    })?;

    let default_theme = rc.evaluate(ctx, "@root/default_theme")?;
-    let default_theme_name = default_theme
-        .as_json()
-        .as_str()
-        .ok_or_else(|| RenderError::new("Type error for `default_theme`, string expected"))?;
+    let default_theme_name = default_theme.as_json().as_str().ok_or_else(|| {
+        RenderErrorReason::ParamTypeMismatchForName(
+            "theme_option",
+            "default_theme".to_owned(),
+            "string".to_owned(),
+        )
+    })?;

    out.write(param)?;
    if param.to_lowercase() == default_theme_name.to_lowercase() {
--- a/src/renderer/html_handlebars/helpers/toc.rs
+++ b/src/renderer/html_handlebars/helpers/toc.rs
@@ -1,10 +1,11 @@
 use std::path::Path;
 use std::{cmp::Ordering, collections::BTreeMap};

-use crate::utils;
-use crate::utils::bracket_escape;
+use crate::utils::special_escape;

-use handlebars::{Context, Handlebars, Helper, HelperDef, Output, RenderContext, RenderError};
+use handlebars::{
+    Context, Handlebars, Helper, HelperDef, Output, RenderContext, RenderError, RenderErrorReason,
+};

 // Handlebars helper to construct TOC
 #[derive(Clone, Copy)]
@@ -15,7 +16,7 @@ pub struct RenderToc {
 impl HelperDef for RenderToc {
    fn call<'reg: 'rc, 'rc>(
        &self,
-        _h: &Helper<'reg, 'rc>,
+        _h: &Helper<'rc>,
        _r: &'reg Handlebars<'_>,
        ctx: &'rc Context,
        rc: &mut RenderContext<'reg, 'rc>,
@@ -26,65 +27,48 @@ impl HelperDef for RenderToc {
        // param is the key of value you want to display
        let chapters = rc.evaluate(ctx, "@root/chapters").and_then(|c| {
            serde_json::value::from_value::<Vec<BTreeMap<String, String>>>(c.as_json().clone())
-                .map_err(|_| RenderError::new("Could not decode the JSON data"))
+                .map_err(|_| {
+                    RenderErrorReason::Other("Could not decode the JSON data".to_owned()).into()
+                })
        })?;
-        let current_path = rc
-            .evaluate(ctx, "@root/path")?
-            .as_json()
-            .as_str()
-            .ok_or_else(|| RenderError::new("Type error for `path`, string expected"))?
-            .replace('\"', "");
-
-        let current_section = rc
-            .evaluate(ctx, "@root/section")?
-            .as_json()
-            .as_str()
-            .map(str::to_owned)
-            .unwrap_or_default();

        let fold_enable = rc
            .evaluate(ctx, "@root/fold_enable")?
            .as_json()
            .as_bool()
-            .ok_or_else(|| RenderError::new("Type error for `fold_enable`, bool expected"))?;
+            .ok_or_else(|| {
+                RenderErrorReason::Other("Type error for `fold_enable`, bool expected".to_owned())
+            })?;

        let fold_level = rc
            .evaluate(ctx, "@root/fold_level")?
            .as_json()
            .as_u64()
-            .ok_or_else(|| RenderError::new("Type error for `fold_level`, u64 expected"))?;
+            .ok_or_else(|| {
+                RenderErrorReason::Other("Type error for `fold_level`, u64 expected".to_owned())
+            })?;
+
+        // If true, then this is the iframe and we need target="_parent"
+        let is_toc_html = rc
+            .evaluate(ctx, "@root/is_toc_html")?
+            .as_json()
+            .as_bool()
+            .unwrap_or(false);

        out.write("<ol class=\"chapter\">")?;

        let mut current_level = 1;
-        // The "index" page, which has this attribute set, is supposed to alias the first chapter in
-        // the book, i.e. the first link. There seems to be no easy way to determine which chapter
-        // the "index" is aliasing from within the renderer, so this is used instead to force the
-        // first link to be active. See further below.
-        let mut is_first_chapter = ctx.data().get("is_index").is_some();

        for item in chapters {
-            // Spacer
-            if item.get("spacer").is_some() {
-                out.write("<li class=\"spacer\"></li>")?;
-                continue;
-            }
-
-            let (section, level) = if let Some(s) = item.get("section") {
+            let (_section, level) = if let Some(s) = item.get("section") {
                (s.as_str(), s.matches('.').count())
            } else {
                ("", 1)
            };

-            let is_expanded =
-                if !fold_enable || (!section.is_empty() && current_section.starts_with(section)) {
-                    // Expand if folding is disabled, or if the section is an
-                    // ancestor or the current section itself.
-                    true
-                } else {
-                    // Levels that are larger than this would be folded.
-                    level - 1 < fold_level as usize
-                };
+            // Expand if folding is disabled, or if levels that are larger than this would not
+            // be folded.
+            let is_expanded = !fold_enable || level - 1 < (fold_level as usize);

            match level.cmp(&current_level) {
                Ordering::Greater => {
@@ -104,14 +88,20 @@ impl HelperDef for RenderToc {
                    write_li_open_tag(out, is_expanded, false)?;
                }
                Ordering::Equal => {
-                    write_li_open_tag(out, is_expanded, item.get("section").is_none())?;
+                    write_li_open_tag(out, is_expanded, !item.contains_key("section"))?;
                }
            }

+            // Spacer
+            if item.contains_key("spacer") {
+                out.write("<li class=\"spacer\"></li>")?;
+                continue;
+            }
+
            // Part title
            if let Some(title) = item.get("part") {
                out.write("<li class=\"part-title\">")?;
-                out.write(&bracket_escape(title))?;
+                out.write(&special_escape(title))?;
                out.write("</li>")?;
                continue;
            }
@@ -129,16 +119,12 @@ impl HelperDef for RenderToc {
                        .replace('\\', "/");

                    // Add link
-                    out.write(&utils::fs::path_to_root(&current_path))?;
                    out.write(&tmp)?;
-                    out.write("\"")?;
-
-                    if path == &current_path || is_first_chapter {
-                        is_first_chapter = false;
-                        out.write(" class=\"active\"")?;
-                    }
-
-                    out.write(">")?;
+                    out.write(if is_toc_html {
+                        "\" target=\"_parent\">"
+                    } else {
+                        "\">"
+                    })?;
                    path_exists = true;
                }
                _ => {
@@ -157,7 +143,7 @@ impl HelperDef for RenderToc {
            }

            if let Some(name) = item.get("name") {
-                out.write(&bracket_escape(name))?
+                out.write(&special_escape(name))?
            }

            if path_exists {
--- a/src/renderer/html_handlebars/search.rs
+++ b/src/renderer/html_handlebars/search.rs
@@ -1,13 +1,13 @@
 use std::borrow::Cow;
 use std::collections::{HashMap, HashSet};
-use std::path::Path;
+use std::path::{Path, PathBuf};

 use elasticlunr::{Index, IndexBuilder};
 use once_cell::sync::Lazy;
 use pulldown_cmark::*;

-use crate::book::{Book, BookItem};
-use crate::config::Search;
+use crate::book::{Book, BookItem, Chapter};
+use crate::config::{Search, SearchChapterSettings};
 use crate::errors::*;
 use crate::theme::searcher;
 use crate::utils;
@@ -35,8 +35,21 @@ pub fn create_files(search_config: &Search, destination: &Path, book: &Book) ->

    let mut doc_urls = Vec::with_capacity(book.sections.len());

+    let chapter_configs = sort_search_config(&search_config.chapter);
+    validate_chapter_config(&chapter_configs, book)?;
+
    for item in book.iter() {
-        render_item(&mut index, search_config, &mut doc_urls, item)?;
+        let chapter = match item {
+            BookItem::Chapter(ch) if !ch.is_draft_chapter() => ch,
+            _ => continue,
+        };
+        if let Some(path) = settings_path(chapter) {
+            let chapter_settings = get_chapter_settings(&chapter_configs, path);
+            if !chapter_settings.enable.unwrap_or(true) {
+                continue;
+            }
+        }
+        render_item(&mut index, search_config, &mut doc_urls, chapter)?;
    }

    let index = write_to_json(index, search_config, doc_urls)?;
@@ -50,7 +63,7 @@ pub fn create_files(search_config: &Search, destination: &Path, book: &Book) ->
        utils::fs::write_file(
            destination,
            "searchindex.js",
-            format!("Object.assign(window.search, {});", index).as_bytes(),
+            format!("Object.assign(window.search, {index});").as_bytes(),
        )?;
        utils::fs::write_file(destination, "searcher.js", searcher::JS)?;
        utils::fs::write_file(destination, "mark.min.js", searcher::MARK_JS)?;
@@ -66,11 +79,24 @@ fn add_doc(
    index: &mut Index,
    doc_urls: &mut Vec<String>,
    anchor_base: &str,
-    section_id: &Option<String>,
+    heading: &str,
+    id_counter: &mut HashMap<String, usize>,
+    section_id: &Option<CowStr<'_>>,
    items: &[&str],
 ) {
-    let url = if let Some(ref id) = *section_id {
-        Cow::Owned(format!("{}#{}", anchor_base, id))
+    // Either use the explicit section id the user specified, or generate one
+    // from the heading content.
+    let section_id = section_id.as_ref().map(|id| id.to_string()).or_else(|| {
+        if heading.is_empty() {
+            // In the case where a chapter has no heading, don't set a section id.
+            None
+        } else {
+            Some(utils::unique_id_from_content(heading, id_counter))
+        }
+    });
+
+    let url = if let Some(id) = section_id {
+        Cow::Owned(format!("{anchor_base}#{id}"))
    } else {
        Cow::Borrowed(anchor_base)
    };
@@ -87,13 +113,8 @@ fn render_item(
    index: &mut Index,
    search_config: &Search,
    doc_urls: &mut Vec<String>,
-    item: &BookItem,
+    chapter: &Chapter,
 ) -> Result<()> {
-    let chapter = match *item {
-        BookItem::Chapter(ref ch) if !ch.is_draft_chapter() => ch,
-        _ => return Ok(()),
-    };
-
    let chapter_path = chapter
        .path
        .as_ref()
@@ -119,7 +140,7 @@ fn render_item(
    let mut id_counter = HashMap::new();
    while let Some(event) = p.next() {
        match event {
-            Event::Start(Tag::Heading(i, ..)) if i as u32 <= max_section_depth => {
+            Event::Start(Tag::Heading { level, id, .. }) if level as u32 <= max_section_depth => {
                if !heading.is_empty() {
                    // Section finished, the next heading is following now
                    // Write the data to the index, and clear it for the next section
@@ -127,22 +148,21 @@ fn render_item(
                        index,
                        doc_urls,
                        &anchor_base,
+                        &heading,
+                        &mut id_counter,
                        &section_id,
                        &[&heading, &body, &breadcrumbs.join(" » ")],
                    );
-                    section_id = None;
                    heading.clear();
                    body.clear();
                    breadcrumbs.pop();
                }

+                section_id = id;
                in_heading = true;
            }
-            Event::End(Tag::Heading(i, id, _classes)) if i as u32 <= max_section_depth => {
+            Event::End(TagEnd::Heading(level)) if level as u32 <= max_section_depth => {
                in_heading = false;
-                section_id = id
-                    .map(|id| id.to_string())
-                    .or_else(|| Some(utils::unique_id_from_content(&heading, &mut id_counter)));
                breadcrumbs.push(heading.clone());
            }
            Event::Start(Tag::FootnoteDefinition(name)) => {
@@ -159,9 +179,19 @@ fn render_item(
                    html_block.push_str(html);
                    p.next();
                }
-
                body.push_str(&clean_html(&html_block));
            }
+            Event::InlineHtml(html) => {
+                // This is not capable of cleaning inline tags like
+                // `foo <script>…</script>`. The `<script>` tags show up as
+                // individual InlineHtml events, and the content inside is
+                // just a regular Text event. There isn't a very good way to
+                // know how to collect all the content in-between. I'm not
+                // sure if this is easily fixable. It should be extremely
+                // rare, since script and style tags should almost always be
+                // blocks, and worse case you have some noise in the index.
+                body.push_str(&clean_html(&html));
+            }
            Event::Start(_) | Event::End(_) | Event::Rule | Event::SoftBreak | Event::HardBreak => {
                // Insert spaces where HTML output would usually separate text
                // to ensure words don't get merged together
@@ -181,25 +211,31 @@ fn render_item(
            Event::FootnoteReference(name) => {
                let len = footnote_numbers.len() + 1;
                let number = footnote_numbers.entry(name).or_insert(len);
-                body.push_str(&format!(" [{}] ", number));
+                body.push_str(&format!(" [{number}] "));
            }
            Event::TaskListMarker(_checked) => {}
        }
    }

    if !body.is_empty() || !heading.is_empty() {
-        if heading.is_empty() {
+        let title = if heading.is_empty() {
            if let Some(chapter) = breadcrumbs.first() {
-                heading = chapter.clone();
+                chapter
+            } else {
+                ""
            }
-        }
+        } else {
+            &heading
+        };
        // Make sure the last section is added to the index
        add_doc(
            index,
            doc_urls,
            &anchor_base,
+            &heading,
+            &mut id_counter,
            &section_id,
-            &[&heading, &body, &breadcrumbs.join(" » ")],
+            &[title, &body, &breadcrumbs.join(" » ")],
        );
    }

@@ -285,3 +321,82 @@ fn clean_html(html: &str) -> String {
    });
    AMMONIA.clean(html).to_string()
 }
+
+fn settings_path(ch: &Chapter) -> Option<&Path> {
+    ch.source_path.as_deref().or_else(|| ch.path.as_deref())
+}
+
+fn validate_chapter_config(
+    chapter_configs: &[(PathBuf, SearchChapterSettings)],
+    book: &Book,
+) -> Result<()> {
+    for (path, _) in chapter_configs {
+        let found = book
+            .iter()
+            .filter_map(|item| match item {
+                BookItem::Chapter(ch) if !ch.is_draft_chapter() => settings_path(ch),
+                _ => None,
+            })
+            .any(|source_path| source_path.starts_with(path));
+        if !found {
+            bail!(
+                "[output.html.search.chapter] key `{}` does not match any chapter paths",
+                path.display()
+            );
+        }
+    }
+    Ok(())
+}
+
+fn sort_search_config(
+    map: &HashMap<String, SearchChapterSettings>,
+) -> Vec<(PathBuf, SearchChapterSettings)> {
+    let mut settings: Vec<_> = map
+        .iter()
+        .map(|(key, value)| (PathBuf::from(key), value.clone()))
+        .collect();
+    // Note: This is case-sensitive, and assumes the author uses the same case
+    // as the actual filename.
+    settings.sort_by(|a, b| a.0.cmp(&b.0));
+    settings
+}
+
+fn get_chapter_settings(
+    chapter_configs: &[(PathBuf, SearchChapterSettings)],
+    source_path: &Path,
+) -> SearchChapterSettings {
+    let mut result = SearchChapterSettings::default();
+    for (path, config) in chapter_configs {
+        if source_path.starts_with(path) {
+            result.enable = config.enable.or(result.enable);
+        }
+    }
+    result
+}
+
+#[test]
+fn chapter_settings_priority() {
+    let cfg = r#"
+        [output.html.search.chapter]
+        "cli/watch.md" = { enable = true }
+        "cli" = { enable = false }
+        "cli/inner/foo.md" = { enable = false }
+        "cli/inner" = { enable = true }
+        "foo" = {} # Just to make sure empty table is allowed.
+    "#;
+    let cfg: crate::Config = toml::from_str(cfg).unwrap();
+    let html = cfg.html_config().unwrap();
+    let chapter_configs = sort_search_config(&html.search.unwrap().chapter);
+    for (path, enable) in [
+        ("foo.md", None),
+        ("cli/watch.md", Some(true)),
+        ("cli/index.md", Some(false)),
+        ("cli/inner/index.md", Some(true)),
+        ("cli/inner/foo.md", Some(false)),
+    ] {
+        assert_eq!(
+            get_chapter_settings(&chapter_configs, Path::new(path)),
+            SearchChapterSettings { enable }
+        );
+    }
+}
--- a/src/theme/book.js
+++ b/src/theme/book.js
@@ -225,7 +225,7 @@ function playground_text(playground, hidden = true) {
                }

                var clipButton = document.createElement('button');
-                clipButton.className = 'fa fa-copy clip-button';
+                clipButton.className = 'clip-button';
                clipButton.title = 'Copy to clipboard';
                clipButton.setAttribute('aria-label', clipButton.title);
                clipButton.innerHTML = '<i class=\"tooltiptext\"></i>';
@@ -258,7 +258,7 @@ function playground_text(playground, hidden = true) {

        if (window.playground_copyable) {
            var copyCodeClipboardButton = document.createElement('button');
-            copyCodeClipboardButton.className = 'fa fa-copy clip-button';
+            copyCodeClipboardButton.className = 'clip-button';
            copyCodeClipboardButton.innerHTML = '<i class="tooltiptext"></i>';
            copyCodeClipboardButton.title = 'Copy to clipboard';
            copyCodeClipboardButton.setAttribute('aria-label', copyCodeClipboardButton.title);
@@ -289,6 +289,10 @@ function playground_text(playground, hidden = true) {
    var themeToggleButton = document.getElementById('theme-toggle');
    var themePopup = document.getElementById('theme-list');
    var themeColorMetaTag = document.querySelector('meta[name="theme-color"]');
+    var themeIds = [];
+    themePopup.querySelectorAll('button.theme').forEach(function (el) {
+        themeIds.push(el.id);
+    });
    var stylesheets = {
        ayuHighlight: document.querySelector("[href$='ayu-highlight.css']"),
        tomorrowNight: document.querySelector("[href$='tomorrow-night.css']"),
@@ -317,7 +321,7 @@ function playground_text(playground, hidden = true) {
    function get_theme() {
        var theme;
        try { theme = localStorage.getItem('mdbook-theme'); } catch (e) { }
-        if (theme === null || theme === undefined) {
+        if (theme === null || theme === undefined || !themeIds.includes(theme)) {
            return default_theme;
        } else {
            return theme;
@@ -346,7 +350,7 @@ function playground_text(playground, hidden = true) {
        }

        setTimeout(function () {
-            themeColorMetaTag.content = getComputedStyle(document.body).backgroundColor;
+            themeColorMetaTag.content = getComputedStyle(document.documentElement).backgroundColor;
        }, 1);

        if (window.ace && window.editors) {
@@ -441,16 +445,17 @@ function playground_text(playground, hidden = true) {
 })();

 (function sidebar() {
-    var html = document.querySelector("html");
+    var body = document.querySelector("body");
    var sidebar = document.getElementById("sidebar");
    var sidebarLinks = document.querySelectorAll('#sidebar a');
    var sidebarToggleButton = document.getElementById("sidebar-toggle");
+    var sidebarToggleAnchor = document.getElementById("sidebar-toggle-anchor");
    var sidebarResizeHandle = document.getElementById("sidebar-resize-handle");
    var firstContact = null;

    function showSidebar() {
-        html.classList.remove('sidebar-hidden')
-        html.classList.add('sidebar-visible');
+        body.classList.remove('sidebar-hidden')
+        body.classList.add('sidebar-visible');
        Array.from(sidebarLinks).forEach(function (link) {
            link.setAttribute('tabIndex', 0);
        });
@@ -459,20 +464,9 @@ function playground_text(playground, hidden = true) {
        try { localStorage.setItem('mdbook-sidebar', 'visible'); } catch (e) { }
    }

-
-    var sidebarAnchorToggles = document.querySelectorAll('#sidebar a.toggle');
-
-    function toggleSection(ev) {
-        ev.currentTarget.parentElement.classList.toggle('expanded');
-    }
-
-    Array.from(sidebarAnchorToggles).forEach(function (el) {
-        el.addEventListener('click', toggleSection);
-    });
-
    function hideSidebar() {
-        html.classList.remove('sidebar-visible')
-        html.classList.add('sidebar-hidden');
+        body.classList.remove('sidebar-visible')
+        body.classList.add('sidebar-hidden');
        Array.from(sidebarLinks).forEach(function (link) {
            link.setAttribute('tabIndex', -1);
        });
@@ -482,22 +476,16 @@ function playground_text(playground, hidden = true) {
    }

    // Toggle sidebar
-    sidebarToggleButton.addEventListener('click', function sidebarToggle() {
-        if (html.classList.contains("sidebar-hidden")) {
+    sidebarToggleAnchor.addEventListener('change', function sidebarToggle() {
+        if (sidebarToggleAnchor.checked) {
            var current_width = parseInt(
                document.documentElement.style.getPropertyValue('--sidebar-width'), 10);
            if (current_width < 150) {
                document.documentElement.style.setProperty('--sidebar-width', '150px');
            }
            showSidebar();
-        } else if (html.classList.contains("sidebar-visible")) {
-            hideSidebar();
        } else {
-            if (getComputedStyle(sidebar)['transform'] === 'none') {
-                hideSidebar();
-            } else {
-                showSidebar();
-            }
+            hideSidebar();
        }
    });

@@ -506,14 +494,14 @@ function playground_text(playground, hidden = true) {
    function initResize(e) {
        window.addEventListener('mousemove', resize, false);
        window.addEventListener('mouseup', stopResize, false);
-        html.classList.add('sidebar-resizing');
+        body.classList.add('sidebar-resizing');
    }
    function resize(e) {
        var pos = (e.clientX - sidebar.offsetLeft);
        if (pos < 20) {
            hideSidebar();
        } else {
-            if (html.classList.contains("sidebar-hidden")) {
+            if (body.classList.contains("sidebar-hidden")) {
                showSidebar();
            }
            pos = Math.min(pos, window.innerWidth - 100);
@@ -522,7 +510,7 @@ function playground_text(playground, hidden = true) {
    }
    //on mouseup remove windows functions mousemove & mouseup
    function stopResize(e) {
-        html.classList.remove('sidebar-resizing');
+        body.classList.remove('sidebar-resizing');
        window.removeEventListener('mousemove', resize, false);
        window.removeEventListener('mouseup', stopResize, false);
    }
@@ -557,20 +545,35 @@ function playground_text(playground, hidden = true) {
    document.addEventListener('keydown', function (e) {
        if (e.altKey || e.ctrlKey || e.metaKey || e.shiftKey) { return; }
        if (window.search && window.search.hasFocus()) { return; }
+        var html = document.querySelector('html');

+        function next() {
+            var nextButton = document.querySelector('.nav-chapters.next');
+            if (nextButton) {
+                window.location.href = nextButton.href;
+            }
+        }
+        function prev() {
+            var previousButton = document.querySelector('.nav-chapters.previous');
+            if (previousButton) {
+                window.location.href = previousButton.href;
+            }
+        }
        switch (e.key) {
            case 'ArrowRight':
                e.preventDefault();
-                var nextButton = document.querySelector('.nav-chapters.next');
-                if (nextButton) {
-                    window.location.href = nextButton.href;
+                if (html.dir == 'rtl') {
+                    prev();
+                } else {
+                    next();
                }
                break;
            case 'ArrowLeft':
                e.preventDefault();
-                var previousButton = document.querySelector('.nav-chapters.previous');
-                if (previousButton) {
-                    window.location.href = previousButton.href;
+                if (html.dir == 'rtl') {
+                    next();
+                } else {
+                    prev();
                }
                break;
        }
@@ -582,12 +585,12 @@ function playground_text(playground, hidden = true) {

    function hideTooltip(elem) {
        elem.firstChild.innerText = "";
-        elem.className = 'fa fa-copy clip-button';
+        elem.className = 'clip-button';
    }

    function showTooltip(elem, msg) {
        elem.firstChild.innerText = msg;
-        elem.className = 'fa fa-copy tooltipped';
+        elem.className = 'clip-button tooltipped';
    }

    var clipboardSnippets = new ClipboardJS('.clip-button', {
--- a/src/theme/css/chrome.css
+++ b/src/theme/css/chrome.css
@@ -1,7 +1,5 @@
 /* CSS for UI elements (a.k.a. chrome) */

-@import 'variables.css';
-
 html {
    scrollbar-color: var(--scrollbar) var(--bg);
 }
@@ -37,14 +35,14 @@ a > .hljs {
    display: flex;
    flex-wrap: wrap;
    background-color: var(--bg);
-    border-bottom-color: var(--bg);
-    border-bottom-width: 1px;
-    border-bottom-style: solid;
+    border-block-end-color: var(--bg);
+    border-block-end-width: 1px;
+    border-block-end-style: solid;
 }
 #menu-bar.sticky,
-.js #menu-bar-hover-placeholder:hover + #menu-bar,
-.js #menu-bar:hover,
-.js.sidebar-visible #menu-bar {
+#menu-bar-hover-placeholder:hover + #menu-bar,
+#menu-bar:hover,
+html.sidebar-visible #menu-bar {
    position: -webkit-sticky;
    position: sticky;
    top: 0 !important;
@@ -56,7 +54,7 @@ a > .hljs {
    height: var(--menu-bar-height);
 }
 #menu-bar.bordered {
-    border-bottom-color: var(--table-border-color);
+    border-block-end-color: var(--table-border-color);
 }
 #menu-bar i, #menu-bar .icon-button {
    position: relative;
@@ -93,7 +91,7 @@ a > .hljs {
    display: flex;
    margin: 0 5px;
 }
-.no-js .left-buttons {
+html:not(.js) .left-buttons button {
    display: none;
 }

@@ -109,7 +107,7 @@ a > .hljs {
    overflow: hidden;
    text-overflow: ellipsis;
 }
-.js .menu-title {
+.menu-title {
    cursor: pointer;
 }

@@ -160,7 +158,7 @@ a > .hljs {
 }

 .nav-wrapper {
-    margin-top: 50px;
+    margin-block-start: 50px;
    display: none;
 }

@@ -173,23 +171,34 @@ a > .hljs {
    background-color: var(--sidebar-bg);
 }

-.previous {
-    float: left;
-}
+/* Only Firefox supports flow-relative values */
+.previous { float: left; }
+[dir=rtl] .previous { float: right; }

+/* Only Firefox supports flow-relative values */
 .next {
    float: right;
    right: var(--page-padding);
 }
+[dir=rtl] .next {
+    float: left;
+    right: unset;
+    left: var(--page-padding);
+}
+
+/* Use the correct buttons for RTL layouts*/
+[dir=rtl] .previous i.fa-angle-left:before {content:"\f105";}
+[dir=rtl] .next i.fa-angle-right:before { content:"\f104"; }

@media only screen and (max-width: 1080px) {
    .nav-wide-wrapper { display: none; }
    .nav-wrapper { display: block; }
 }

+/* sidebar-visible */
@media only screen and (max-width: 1380px) {
-    .sidebar-visible .nav-wide-wrapper { display: none; }
-    .sidebar-visible .nav-wrapper { display: block; }
+    #sidebar-toggle-anchor:checked ~ .page-wrapper .nav-wide-wrapper { display: none; }
+    #sidebar-toggle-anchor:checked ~ .page-wrapper .nav-wrapper { display: block; }
 }

 /* Inline code */
@@ -236,13 +245,13 @@ pre > .buttons :hover {
    background-color: var(--theme-hover);
 }
 pre > .buttons i {
-    margin-left: 8px;
+    margin-inline-start: 8px;
 }
 pre > .buttons button {
    cursor: inherit;
    margin: 0px 5px;
-    padding: 3px 5px;
-    font-size: 14px;
+    padding: 4px 4px 3px 5px;
+    font-size: 23px;

    border-style: solid;
    border-width: 1px;
@@ -253,13 +262,40 @@ pre > .buttons button {
    transition-property: color,border-color,background-color;
    color: var(--icons);
 }
+
+pre > .buttons button.clip-button {
+    padding: 2px 4px 0px 6px;
+}
+pre > .buttons button.clip-button::before {
+    /* clipboard image from octicons (https://github.com/primer/octicons/tree/v2.0.0) MIT license
+     */
+    content: url('data:image/svg+xml,<svg width="21" height="20" viewBox="0 0 24 25" \
+xmlns="http://www.w3.org/2000/svg" aria-label="Copy to clipboard">\
+<path d="M18 20h2v3c0 1-1 2-2 2H2c-.998 0-2-1-2-2V5c0-.911.755-1.667 1.667-1.667h5A3.323 3.323 0 \
+0110 0a3.323 3.323 0 013.333 3.333h5C19.245 3.333 20 4.09 20 5v8.333h-2V9H2v14h16v-3zM3 \
+7h14c0-.911-.793-1.667-1.75-1.667H13.5c-.957 0-1.75-.755-1.75-1.666C11.75 2.755 10.957 2 10 \
+2s-1.75.755-1.75 1.667c0 .911-.793 1.666-1.75 1.666H4.75C3.793 5.333 3 6.09 3 7z"/>\
+<path d="M4 19h6v2H4zM12 11H4v2h8zM4 17h4v-2H4zM15 15v-3l-4.5 4.5L15 21v-3l8.027-.032L23 15z"/>\
+</svg>');
+    filter: var(--copy-button-filter);
+}
+pre > .buttons button.clip-button:hover::before {
+    filter: var(--copy-button-filter-hover);
+}
+
@media (pointer: coarse) {
    pre > .buttons button {
        /* On mobile, make it easier to tap buttons. */
        padding: 0.3rem 1rem;
    }
+
+    .sidebar-resize-indicator {
+        /* Hide resize indicator on devices with limited accuracy */
+        display: none;
+    }
 }
 pre > code {
+    display: block;
    padding: 1rem;
 }

@@ -273,7 +309,7 @@ pre > code {
 }

 pre > .result {
-    margin-top: 10px;
+    margin-block-start: 10px;
 }

 /* Search */
@@ -284,8 +320,14 @@ pre > .result {

 mark {
    border-radius: 2px;
-    padding: 0 3px 1px 3px;
-    margin: 0 -3px -1px -3px;
+    padding-block-start: 0;
+    padding-block-end: 1px;
+    padding-inline-start: 3px;
+    padding-inline-end: 3px;
+    margin-block-start: 0;
+    margin-block-end: -1px;
+    margin-inline-start: -3px;
+    margin-inline-end: -3px;
    background-color: var(--search-mark-bg);
    transition: background-color 300ms linear;
    cursor: pointer;
@@ -297,14 +339,17 @@ mark.fade-out {
 }

 .searchbar-outer {
-    margin-left: auto;
-    margin-right: auto;
+    margin-inline-start: auto;
+    margin-inline-end: auto;
    max-width: var(--content-max-width);
 }

 #searchbar {
    width: 100%;
-    margin: 5px auto 0px auto;
+    margin-block-start: 5px;
+    margin-block-end: 0;
+    margin-inline-start: auto;
+    margin-inline-end: auto;
    padding: 10px 16px;
    transition: box-shadow 300ms ease-in-out;
    border: 1px solid var(--searchbar-border-color);
@@ -320,20 +365,23 @@ mark.fade-out {
 .searchresults-header {
    font-weight: bold;
    font-size: 1em;
-    padding: 18px 0 0 5px;
+    padding-block-start: 18px;
+    padding-block-end: 0;
+    padding-inline-start: 5px;
+    padding-inline-end: 0;
    color: var(--searchresults-header-fg);
 }

 .searchresults-outer {
-    margin-left: auto;
-    margin-right: auto;
+    margin-inline-start: auto;
+    margin-inline-end: auto;
    max-width: var(--content-max-width);
-    border-bottom: 1px dashed var(--searchresults-border-color);
+    border-block-end: 1px dashed var(--searchresults-border-color);
 }

 ul#searchresults {
    list-style: none;
-    padding-left: 20px;
+    padding-inline-start: 20px;
 }
 ul#searchresults li {
    margin: 10px 0px;
@@ -346,7 +394,10 @@ ul#searchresults li.focus {
 ul#searchresults span.teaser {
    display: block;
    clear: both;
-    margin: 5px 0 0 20px;
+    margin-block-start: 5px;
+    margin-block-end: 0;
+    margin-inline-start: 20px;
+    margin-inline-end: 0;
    font-size: 0.8em;
 }
 ul#searchresults span.teaser em {
@@ -369,13 +420,33 @@ ul#searchresults span.teaser em {
    background-color: var(--sidebar-bg);
    color: var(--sidebar-fg);
 }
+.sidebar-iframe-inner {
+    --padding: 10px;
+
+    background-color: var(--sidebar-bg);
+    padding: var(--padding);
+    margin: 0;
+    font-size: 1.4rem;
+    color: var(--sidebar-fg);
+    min-height: calc(100vh - var(--padding) * 2);
+}
+.sidebar-iframe-outer {
+    border: none;
+    height: 100%;
+    position: absolute;
+    top: 0;
+    bottom: 0;
+    left: 0;
+    right: 0;
+}
+[dir=rtl] .sidebar { left: unset; right: 0; }
 .sidebar-resizing {
    -moz-user-select: none;
    -webkit-user-select: none;
    -ms-user-select: none;
    user-select: none;
 }
-.js:not(.sidebar-resizing) .sidebar {
+html:not(.sidebar-resizing) .sidebar {
    transition: transform 0.3s; /* Animation: slide away */
 }
 .sidebar code {
@@ -394,16 +465,35 @@ ul#searchresults span.teaser em {
    position: absolute;
    cursor: col-resize;
    width: 0;
-    right: 0;
+    right: calc(var(--sidebar-resize-indicator-width) * -1);
    top: 0;
    bottom: 0;
+    display: flex;
+    align-items: center;
+}
+
+.sidebar-resize-handle .sidebar-resize-indicator {
+    width: 100%;
+    height: 12px;
+    background-color: var(--icons);
+    margin-inline-start: var(--sidebar-resize-indicator-space);
+}
+
+[dir=rtl] .sidebar .sidebar-resize-handle {
+    left: calc(var(--sidebar-resize-indicator-width) * -1);
+    right: unset;
 }
 .js .sidebar .sidebar-resize-handle {
    cursor: col-resize;
-    width: 5px;
+    width: calc(var(--sidebar-resize-indicator-width) - var(--sidebar-resize-indicator-space));
 }
-.sidebar-hidden .sidebar {
-    transform: translateX(calc(0px - var(--sidebar-width)));
+/* sidebar-hidden */
+#sidebar-toggle-anchor:not(:checked) ~ .sidebar {
+    transform: translateX(calc(0px - var(--sidebar-width) - var(--sidebar-resize-indicator-width)));
+    z-index: -1;
+}
+[dir=rtl] #sidebar-toggle-anchor:not(:checked) ~ .sidebar {
+    transform: translateX(calc(var(--sidebar-width) + var(--sidebar-resize-indicator-width)));
 }
 .sidebar::-webkit-scrollbar {
    background: var(--sidebar-bg);
@@ -412,19 +502,26 @@ ul#searchresults span.teaser em {
    background: var(--scrollbar);
 }

-.sidebar-visible .page-wrapper {
-    transform: translateX(var(--sidebar-width));
+/* sidebar-visible */
+#sidebar-toggle-anchor:checked ~ .page-wrapper {
+    transform: translateX(calc(var(--sidebar-width) + var(--sidebar-resize-indicator-width)));
+}
+[dir=rtl] #sidebar-toggle-anchor:checked ~ .page-wrapper {
+    transform: translateX(calc(0px - var(--sidebar-width) - var(--sidebar-resize-indicator-width)));
 }
@media only screen and (min-width: 620px) {
-    .sidebar-visible .page-wrapper {
+    #sidebar-toggle-anchor:checked ~ .page-wrapper {
+        transform: none;
+        margin-inline-start: calc(var(--sidebar-width) + var(--sidebar-resize-indicator-width));
+    }
+    [dir=rtl] #sidebar-toggle-anchor:checked ~ .page-wrapper {
        transform: none;
-        margin-left: var(--sidebar-width);
    }
 }

 .chapter {
    list-style: none outside none;
-    padding-left: 0;
+    padding-inline-start: 0;
    line-height: 2.2em;
 }

@@ -454,7 +551,7 @@ ul#searchresults span.teaser em {
 .chapter li > a.toggle {
    cursor: pointer;
    display: block;
-    margin-left: auto;
+    margin-inline-start: auto;
    padding: 0 10px;
    user-select: none;
    opacity: 0.68;
@@ -471,7 +568,7 @@ ul#searchresults span.teaser em {

 .chapter li.chapter-item {
    line-height: 1.5em;
-    margin-top: 0.6em;
+    margin-block-start: 0.6em;
 }

 .chapter li.expanded > a.toggle div {
@@ -494,7 +591,7 @@ ul#searchresults span.teaser em {

 .section {
    list-style: none outside none;
-    padding-left: 20px;
+    padding-inline-start: 20px;
    line-height: 1.9em;
 }

@@ -517,6 +614,7 @@ ul#searchresults span.teaser em {
    /* Don't let the children's background extend past the rounded corners. */
    overflow: hidden;
 }
+[dir=rtl] .theme-popup { left: unset;  right: 10px; }
 .theme-popup .default {
    color: var(--icons);
 }
@@ -527,7 +625,7 @@ ul#searchresults span.teaser em {
    padding: 2px 20px;
    line-height: 25px;
    white-space: nowrap;
-    text-align: left;
+    text-align: start;
    cursor: pointer;
    color: inherit;
    background: inherit;
@@ -540,6 +638,6 @@ ul#searchresults span.teaser em {
 .theme-selected::before {
    display: inline-block;
    content: "✓";
-    margin-left: -14px;
+    margin-inline-start: -14px;
    width: 14px;
 }
--- a/src/theme/css/general.css
+++ b/src/theme/css/general.css
@@ -1,10 +1,9 @@
 /* Base styles and content styles */

-@import 'variables.css';
-
 :root {
    /* Browser default font-size is 16px, this way 1 rem = 10px */
    font-size: 62.5%;
+    color-scheme: var(--color-scheme);
 }

 html {
@@ -24,6 +23,7 @@ body {
 code {
    font-family: var(--mono-font) !important;
    font-size: var(--code-font-size);
+    direction: ltr !important;
 }

 /* make long words/inline code not x overflow */
@@ -47,13 +47,13 @@ h1 code, h2 code, h3 code, h4 code, h5 code, h6 code {
 .hide-boring .boring { display: none; }
 .hidden { display: none !important; }

-h2, h3 { margin-top: 2.5em; }
-h4, h5 { margin-top: 2em; }
+h2, h3 { margin-block-start: 2.5em; }
+h4, h5 { margin-block-start: 2em; }

 .header + .header h3,
 .header + .header h4,
 .header + .header h5 {
-    margin-top: 1em;
+    margin-block-start: 1em;
 }

 h1:target::before,
@@ -64,7 +64,7 @@ h5:target::before,
 h6:target::before {
    display: inline-block;
    content: "»";
-    margin-left: -30px;
+    margin-inline-start: -30px;
    width: 30px;
 }

@@ -73,28 +73,34 @@ h6:target::before {
   https://bugs.webkit.org/show_bug.cgi?id=218076
 */
 :target {
+    /* Safari does not support logical properties */
    scroll-margin-top: calc(var(--menu-bar-height) + 0.5em);
 }

 .page {
    outline: 0;
    padding: 0 var(--page-padding);
-    margin-top: calc(0px - var(--menu-bar-height)); /* Compensate for the #menu-bar-hover-placeholder */
+    margin-block-start: calc(0px - var(--menu-bar-height)); /* Compensate for the #menu-bar-hover-placeholder */
 }
 .page-wrapper {
    box-sizing: border-box;
+    background-color: var(--bg);
 }
+.no-js .page-wrapper,
 .js:not(.sidebar-resizing) .page-wrapper {
    transition: margin-left 0.3s ease, transform 0.3s ease; /* Animation: slide away */
 }
+[dir=rtl] .js:not(.sidebar-resizing) .page-wrapper {
+    transition: margin-right 0.3s ease, transform 0.3s ease; /* Animation: slide away */
+}

 .content {
    overflow-y: auto;
    padding: 0 5px 50px 5px;
 }
 .content main {
-    margin-left: auto;
-    margin-right: auto;
+    margin-inline-start: auto;
+    margin-inline-end: auto;
    max-width: var(--content-max-width);
 }
 .content p { line-height: 1.45em; }
@@ -144,8 +150,31 @@ blockquote {
    padding: 0 20px;
    color: var(--fg);
    background-color: var(--quote-bg);
-    border-top: .1em solid var(--quote-border);
-    border-bottom: .1em solid var(--quote-border);
+    border-block-start: .1em solid var(--quote-border);
+    border-block-end: .1em solid var(--quote-border);
+}
+
+.warning {
+    margin: 20px;
+    padding: 0 20px;
+    border-inline-start: 2px solid var(--warning-border);
+}
+
+.warning:before {
+    position: absolute;
+    width: 3rem;
+    height: 3rem;
+    margin-inline-start: calc(-1.5rem - 21px);
+    content: "ⓘ";
+    text-align: center;
+    background-color: var(--bg);
+    color: var(--warning-border);
+    font-weight: bold;
+    font-size: 2rem;
+}
+
+blockquote .warning:before {
+    background-color: var(--quote-bg);
 }

 kbd {
@@ -161,9 +190,21 @@ kbd {
    vertical-align: middle;
 }

-:not(.footnote-definition) + .footnote-definition,
-.footnote-definition + :not(.footnote-definition) {
-    margin-top: 2em;
+sup {
+    /* Set the line-height for superscript and footnote references so that there
+       isn't an awkward space appearing above lines that contain the footnote.
+
+       See https://github.com/rust-lang/mdBook/pull/2443#discussion_r1813773583
+       for an explanation.
+    */
+    line-height: 0;
+}
+
+:not(.footnote-definition) + .footnote-definition {
+    margin-block-start: 2em;
+}
+.footnote-definition:not(:has(+ .footnote-definition)) {
+    margin-block-end: 2em;
 }
 .footnote-definition {
    font-size: 0.9em;
--- a/src/theme/css/print.css
+++ b/src/theme/css/print.css
@@ -7,8 +7,8 @@
 }

 #page-wrapper.page-wrapper {
-    transform: none;
-    margin-left: 0px;
+    transform: none !important;
+    margin-inline-start: 0px;
    overflow-y: initial;
 }

@@ -23,11 +23,7 @@
 }

 code {
-    background-color: #666666;
-    border-radius: 5px;
-
-    /* Force background to be printed in Chrome */
-    -webkit-print-color-adjust: exact;
+    direction: ltr !important;
 }

 pre > .buttons {
--- a/src/theme/css/variables.css
+++ b/src/theme/css/variables.css
@@ -3,11 +3,13 @@

 :root {
    --sidebar-width: 300px;
+    --sidebar-resize-indicator-width: 8px;
+    --sidebar-resize-indicator-space: 2px;
    --page-padding: 15px;
    --content-max-width: 750px;
    --menu-bar-height: 50px;
    --mono-font: "Source Code Pro", Consolas, "Ubuntu Mono", Menlo, "DejaVu Sans Mono", monospace, monospace;
-    --code-font-size: 0.875em /* please adjust the ace font size accordingly in editor.js */
+    --code-font-size: 0.875em; /* please adjust the ace font size accordingly in editor.js */
 }

 /* Themes */
@@ -38,6 +40,8 @@
    --quote-bg: hsl(226, 15%, 17%);
    --quote-border: hsl(226, 15%, 22%);

+    --warning-border: #ff8e00;
+
    --table-border-color: hsl(210, 25%, 13%);
    --table-header-bg: hsl(210, 25%, 28%);
    --table-alternate-bg: hsl(210, 25%, 11%);
@@ -50,6 +54,13 @@
    --searchresults-border-color: #888;
    --searchresults-li-bg: #252932;
    --search-mark-bg: #e3b171;
+
+    --color-scheme: dark;
+
+    /* Same as `--icons` */
+    --copy-button-filter: invert(45%) sepia(6%) saturate(621%) hue-rotate(198deg) brightness(99%) contrast(85%);
+    /* Same as `--sidebar-active` */
+    --copy-button-filter-hover: invert(68%) sepia(55%) saturate(531%) hue-rotate(341deg) brightness(104%) contrast(101%);
 }

 .coal {
@@ -78,6 +89,8 @@
    --quote-bg: hsl(234, 21%, 18%);
    --quote-border: hsl(234, 21%, 23%);

+    --warning-border: #ff8e00;
+
    --table-border-color: hsl(200, 7%, 13%);
    --table-header-bg: hsl(200, 7%, 28%);
    --table-alternate-bg: hsl(200, 7%, 11%);
@@ -90,9 +103,16 @@
    --searchresults-border-color: #98a3ad;
    --searchresults-li-bg: #2b2b2f;
    --search-mark-bg: #355c7d;
+
+    --color-scheme: dark;
+
+    /* Same as `--icons` */
+    --copy-button-filter: invert(26%) sepia(8%) saturate(575%) hue-rotate(169deg) brightness(87%) contrast(82%);
+    /* Same as `--sidebar-active` */
+    --copy-button-filter-hover: invert(36%) sepia(70%) saturate(503%) hue-rotate(167deg) brightness(98%) contrast(89%);
 }

-.light {
+.light, html:not(.js) {
    --bg: hsl(0, 0%, 100%);
    --fg: hsl(0, 0%, 0%);

@@ -118,6 +138,8 @@
    --quote-bg: hsl(197, 37%, 96%);
    --quote-border: hsl(197, 37%, 91%);

+    --warning-border: #ff8e00;
+
    --table-border-color: hsl(0, 0%, 95%);
    --table-header-bg: hsl(0, 0%, 80%);
    --table-alternate-bg: hsl(0, 0%, 97%);
@@ -130,6 +152,13 @@
    --searchresults-border-color: #888;
    --searchresults-li-bg: #e4f2fe;
    --search-mark-bg: #a2cff5;
+
+    --color-scheme: light;
+
+    /* Same as `--icons` */
+    --copy-button-filter: invert(45.49%);
+    /* Same as `--sidebar-active` */
+    --copy-button-filter-hover: invert(14%) sepia(93%) saturate(4250%) hue-rotate(243deg) brightness(99%) contrast(130%);
 }

 .navy {
@@ -158,6 +187,8 @@
    --quote-bg: hsl(226, 15%, 17%);
    --quote-border: hsl(226, 15%, 22%);

+    --warning-border: #ff8e00;
+
    --table-border-color: hsl(226, 23%, 16%);
    --table-header-bg: hsl(226, 23%, 31%);
    --table-alternate-bg: hsl(226, 23%, 14%);
@@ -170,6 +201,13 @@
    --searchresults-border-color: #5c5c68;
    --searchresults-li-bg: #242430;
    --search-mark-bg: #a2cff5;
+
+    --color-scheme: dark;
+
+    /* Same as `--icons` */
+    --copy-button-filter: invert(51%) sepia(10%) saturate(393%) hue-rotate(198deg) brightness(86%) contrast(87%);
+    /* Same as `--sidebar-active` */
+    --copy-button-filter-hover: invert(46%) sepia(20%) saturate(1537%) hue-rotate(156deg) brightness(85%) contrast(90%);
 }

 .rust {
@@ -198,6 +236,8 @@
    --quote-bg: hsl(60, 5%, 75%);
    --quote-border: hsl(60, 5%, 70%);

+    --warning-border: #ff8e00;
+
    --table-border-color: hsl(60, 9%, 82%);
    --table-header-bg: #b3a497;
    --table-alternate-bg: hsl(60, 9%, 84%);
@@ -210,10 +250,15 @@
    --searchresults-border-color: #888;
    --searchresults-li-bg: #dec2a2;
    --search-mark-bg: #e69f67;
+
+    /* Same as `--icons` */
+    --copy-button-filter: invert(51%) sepia(10%) saturate(393%) hue-rotate(198deg) brightness(86%) contrast(87%);
+    /* Same as `--sidebar-active` */
+    --copy-button-filter-hover: invert(77%) sepia(16%) saturate(1798%) hue-rotate(328deg) brightness(98%) contrast(83%);
 }

@media (prefers-color-scheme: dark) {
-    .light.no-js {
+    html:not(.js) {
        --bg: hsl(200, 7%, 8%);
        --fg: #98a3ad;

@@ -239,6 +284,8 @@
        --quote-bg: hsl(234, 21%, 18%);
        --quote-border: hsl(234, 21%, 23%);

+        --warning-border: #ff8e00;
+
        --table-border-color: hsl(200, 7%, 13%);
        --table-header-bg: hsl(200, 7%, 28%);
        --table-alternate-bg: hsl(200, 7%, 11%);
@@ -251,5 +298,12 @@
        --searchresults-border-color: #98a3ad;
        --searchresults-li-bg: #2b2b2f;
        --search-mark-bg: #355c7d;
+
+        --color-scheme: dark;
+
+        /* Same as `--icons` */
+        --copy-button-filter: invert(26%) sepia(8%) saturate(575%) hue-rotate(169deg) brightness(87%) contrast(82%);
+        /* Same as `--sidebar-active` */
+        --copy-button-filter-hover: invert(36%) sepia(70%) saturate(503%) hue-rotate(167deg) brightness(98%) contrast(89%);
    }
 }
--- a/src/theme/highlight.css
+++ b/src/theme/highlight.css
@@ -16,6 +16,7 @@
 .hljs-variable,
 .hljs-template-variable,
 .hljs-attribute,
+.hljs-attr,
 .hljs-tag,
 .hljs-name,
 .hljs-regexp,
--- a/src/theme/highlight.js
+++ b/src/theme/highlight.js
--- a/src/theme/index.hbs
+++ b/src/theme/index.hbs
@@ -1,11 +1,11 @@
 <!DOCTYPE HTML>
-<html lang="{{ language }}" class="sidebar-visible no-js {{ default_theme }}">
+<html lang="{{ language }}" class="{{ default_theme }} sidebar-visible" dir="{{ text_direction }}">
    <head>
        <!-- Book generated using mdBook -->
        <meta charset="UTF-8">
        <title>{{ title }}</title>
        {{#if is_print }}
-        <meta name="robots" content="noindex" />
+        <meta name="robots" content="noindex">
        {{/if}}
        {{#if base_url}}
        <base href="{{ base_url }}">
@@ -17,7 +17,7 @@

        <meta name="description" content="{{ description }}">
        <meta name="viewport" content="width=device-width, initial-scale=1">
-        <meta name="theme-color" content="#ffffff" />
+        <meta name="theme-color" content="#ffffff">

        {{#if favicon_svg}}
        <link rel="icon" href="{{ path_to_root }}favicon.svg">
@@ -52,15 +52,17 @@
        <!-- MathJax -->
        <script async src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
        {{/if}}
-    </head>
-    <body>
-    <div id="body-container">
+
        <!-- Provide site root to javascript -->
        <script>
            var path_to_root = "{{ path_to_root }}";
            var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "{{ preferred_dark_theme }}" : "{{ default_theme }}";
        </script>
-
+        <!-- Start loading toc.js asap -->
+        <script src="{{ path_to_root }}toc.js"></script>
+    </head>
+    <body>
+    <div id="body-container">
        <!-- Work around some values being stored in localStorage wrapped in quotes -->
        <script>
            try {
@@ -82,56 +84,40 @@
            var theme;
            try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
            if (theme === null || theme === undefined) { theme = default_theme; }
-            var html = document.querySelector('html');
-            html.classList.remove('no-js')
+            const html = document.documentElement;
            html.classList.remove('{{ default_theme }}')
            html.classList.add(theme);
-            html.classList.add('js');
+            html.classList.add("js");
        </script>

+        <input type="checkbox" id="sidebar-toggle-anchor" class="hidden">
+
        <!-- Hide / unhide sidebar before it is displayed -->
        <script>
-            var html = document.querySelector('html');
            var sidebar = null;
+            var sidebar_toggle = document.getElementById("sidebar-toggle-anchor");
            if (document.body.clientWidth >= 1080) {
                try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
                sidebar = sidebar || 'visible';
            } else {
                sidebar = 'hidden';
            }
+            sidebar_toggle.checked = sidebar === 'visible';
            html.classList.remove('sidebar-visible');
            html.classList.add("sidebar-" + sidebar);
        </script>

        <nav id="sidebar" class="sidebar" aria-label="Table of contents">
-            <div class="sidebar-scrollbox">
-                {{#toc}}{{/toc}}
+            <!-- populated by js -->
+            <mdbook-sidebar-scrollbox class="sidebar-scrollbox"></mdbook-sidebar-scrollbox>
+            <noscript>
+                <iframe class="sidebar-iframe-outer" src="{{ path_to_root }}toc.html"></iframe>
+            </noscript>
+            <div id="sidebar-resize-handle" class="sidebar-resize-handle">
+                <div class="sidebar-resize-indicator"></div>
            </div>
-            <div id="sidebar-resize-handle" class="sidebar-resize-handle"></div>
        </nav>

-        <!-- Track and set sidebar scroll position -->
-        <script>
-            var sidebarScrollbox = document.querySelector('#sidebar .sidebar-scrollbox');
-            sidebarScrollbox.addEventListener('click', function(e) {
-                if (e.target.tagName === 'A') {
-                    sessionStorage.setItem('sidebar-scroll', sidebarScrollbox.scrollTop);
-                }
-            }, { passive: true });
-            var sidebarScrollTop = sessionStorage.getItem('sidebar-scroll');
-            sessionStorage.removeItem('sidebar-scroll');
-            if (sidebarScrollTop) {
-                // preserve sidebar scroll position when navigating via links within sidebar
-                sidebarScrollbox.scrollTop = sidebarScrollTop;
-            } else {
-                // scroll sidebar to current active section when navigating via "next/previous chapter" buttons
-                var activeSection = document.querySelector('#sidebar .active');
-                if (activeSection) {
-                    activeSection.scrollIntoView({ block: 'center' });
-                }
-            }
-        </script>
-
        <div id="page-wrapper" class="page-wrapper">

            <div class="page">
@@ -139,9 +125,9 @@
                <div id="menu-bar-hover-placeholder"></div>
                <div id="menu-bar" class="menu-bar sticky">
                    <div class="left-buttons">
-                        <button id="sidebar-toggle" class="icon-button" type="button" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
+                        <label id="sidebar-toggle" class="icon-button" for="sidebar-toggle-anchor" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
                            <i class="fa fa-bars"></i>
-                        </button>
+                        </label>
                        <button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
                            <i class="fa fa-paint-brush"></i>
                        </button>
@@ -217,7 +203,7 @@
                        {{/previous}}

                        {{#next}}
-                            <a rel="next" href="{{ path_to_root }}{{link}}" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
+                            <a rel="next prefetch" href="{{ path_to_root }}{{link}}" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
                                <i class="fa fa-angle-right"></i>
                            </a>
                        {{/next}}
@@ -235,7 +221,7 @@
                {{/previous}}

                {{#next}}
-                    <a rel="next" href="{{ path_to_root }}{{link}}" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
+                    <a rel="next prefetch" href="{{ path_to_root }}{{link}}" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
                        <i class="fa fa-angle-right"></i>
                    </a>
                {{/next}}
--- a/src/theme/mod.rs
+++ b/src/theme/mod.rs
@@ -17,6 +17,8 @@ pub static INDEX: &[u8] = include_bytes!("index.hbs");
 pub static HEAD: &[u8] = include_bytes!("head.hbs");
 pub static REDIRECT: &[u8] = include_bytes!("redirect.hbs");
 pub static HEADER: &[u8] = include_bytes!("header.hbs");
+pub static TOC_JS: &[u8] = include_bytes!("toc.js.hbs");
+pub static TOC_HTML: &[u8] = include_bytes!("toc.html.hbs");
 pub static CHROME_CSS: &[u8] = include_bytes!("css/chrome.css");
 pub static GENERAL_CSS: &[u8] = include_bytes!("css/general.css");
 pub static PRINT_CSS: &[u8] = include_bytes!("css/print.css");
@@ -50,6 +52,8 @@ pub struct Theme {
    pub head: Vec<u8>,
    pub redirect: Vec<u8>,
    pub header: Vec<u8>,
+    pub toc_js: Vec<u8>,
+    pub toc_html: Vec<u8>,
    pub chrome_css: Vec<u8>,
    pub general_css: Vec<u8>,
    pub print_css: Vec<u8>,
@@ -85,6 +89,8 @@ impl Theme {
                (theme_dir.join("head.hbs"), &mut theme.head),
                (theme_dir.join("redirect.hbs"), &mut theme.redirect),
                (theme_dir.join("header.hbs"), &mut theme.header),
+                (theme_dir.join("toc.js.hbs"), &mut theme.toc_js),
+                (theme_dir.join("toc.html.hbs"), &mut theme.toc_html),
                (theme_dir.join("book.js"), &mut theme.js),
                (theme_dir.join("css/chrome.css"), &mut theme.chrome_css),
                (theme_dir.join("css/general.css"), &mut theme.general_css),
@@ -174,6 +180,8 @@ impl Default for Theme {
            head: HEAD.to_owned(),
            redirect: REDIRECT.to_owned(),
            header: HEADER.to_owned(),
+            toc_js: TOC_JS.to_owned(),
+            toc_html: TOC_HTML.to_owned(),
            chrome_css: CHROME_CSS.to_owned(),
            general_css: GENERAL_CSS.to_owned(),
            print_css: PRINT_CSS.to_owned(),
@@ -212,7 +220,6 @@ fn load_file_contents<P: AsRef<Path>>(filename: P, dest: &mut Vec<u8>) -> Result
 mod tests {
    use super::*;
    use std::fs;
-    use std::path::PathBuf;
    use tempfile::Builder as TempFileBuilder;

    #[test]
@@ -233,6 +240,8 @@ mod tests {
            "head.hbs",
            "redirect.hbs",
            "header.hbs",
+            "toc.js.hbs",
+            "toc.html.hbs",
            "favicon.png",
            "favicon.svg",
            "css/chrome.css",
@@ -264,6 +273,8 @@ mod tests {
            head: Vec::new(),
            redirect: Vec::new(),
            header: Vec::new(),
+            toc_js: Vec::new(),
+            toc_html: Vec::new(),
            chrome_css: Vec::new(),
            general_css: Vec::new(),
            print_css: Vec::new(),
--- a/src/theme/searcher/searcher.js
+++ b/src/theme/searcher/searcher.js
@@ -316,7 +316,7 @@ window.search = window.search || {};
    
    // Eventhandler for keyevents on `document`
    function globalKeyHandler(e) {
-        if (e.altKey || e.ctrlKey || e.metaKey || e.shiftKey || e.target.type === 'textarea' || e.target.type === 'text') { return; }
+        if (e.altKey || e.ctrlKey || e.metaKey || e.shiftKey || e.target.type === 'textarea' || e.target.type === 'text' || !hasFocus() && /^(?:input|select|textarea)$/i.test(e.target.nodeName)) { return; }

        if (e.keyCode === ESCAPE_KEYCODE) {
            e.preventDefault();
--- a/src/theme/toc.html.hbs
+++ b/src/theme/toc.html.hbs
@@ -0,0 +1,43 @@
+<!DOCTYPE HTML>
+<html lang="{{ language }}" class="{{ default_theme }}" dir="{{ text_direction }}">
+    <head>
+        <!-- sidebar iframe generated using mdBook
+
+        This is a frame, and not included directly in the page, to control the total size of the
+        book. The TOC contains an entry for each page, so if each page includes a copy of the TOC,
+        the total size of the page becomes O(n**2).
+
+        The frame is only used as a fallback when JS is turned off. When it's on, the sidebar is
+        instead added to the main page by `toc.js` instead. The JavaScript mode is better
+        because, when running in a `file:///` URL, the iframed page would not be Same-Origin as
+        the rest of the page, so the sidebar and the main page theme would fall out of sync.
+        -->
+        <meta charset="UTF-8">
+        <meta name="robots" content="noindex">
+        {{#if base_url}}
+        <base href="{{ base_url }}">
+        {{/if}}
+        <!-- Custom HTML head -->
+        {{> head}}
+        <meta name="viewport" content="width=device-width, initial-scale=1">
+        <meta name="theme-color" content="#ffffff">
+        <link rel="stylesheet" href="{{ path_to_root }}css/variables.css">
+        <link rel="stylesheet" href="{{ path_to_root }}css/general.css">
+        <link rel="stylesheet" href="{{ path_to_root }}css/chrome.css">
+        {{#if print_enable}}
+        <link rel="stylesheet" href="{{ path_to_root }}css/print.css" media="print">
+        {{/if}}
+        <!-- Fonts -->
+        <link rel="stylesheet" href="{{ path_to_root }}FontAwesome/css/font-awesome.css">
+        {{#if copy_fonts}}
+        <link rel="stylesheet" href="{{ path_to_root }}fonts/fonts.css">
+        {{/if}}
+        <!-- Custom theme stylesheets -->
+        {{#each additional_css}}
+        <link rel="stylesheet" href="{{ ../path_to_root }}{{ this }}">
+        {{/each}}
+    </head>
+    <body class="sidebar-iframe-inner">
+        {{#toc}}{{/toc}}
+    </body>
+</html>
--- a/src/theme/toc.js.hbs
+++ b/src/theme/toc.js.hbs
@@ -0,0 +1,70 @@
+// Populate the sidebar
+//
+// This is a script, and not included directly in the page, to control the total size of the book.
+// The TOC contains an entry for each page, so if each page includes a copy of the TOC,
+// the total size of the page becomes O(n**2).
+class MDBookSidebarScrollbox extends HTMLElement {
+    constructor() {
+        super();
+    }
+    connectedCallback() {
+        this.innerHTML = '{{#toc}}{{/toc}}';
+        // Set the current, active page, and reveal it if it's hidden
+        let current_page = document.location.href.toString().split("#")[0];
+        if (current_page.endsWith("/")) {
+            current_page += "index.html";
+        }
+        var links = Array.prototype.slice.call(this.querySelectorAll("a"));
+        var l = links.length;
+        for (var i = 0; i < l; ++i) {
+            var link = links[i];
+            var href = link.getAttribute("href");
+            if (href && !href.startsWith("#") && !/^(?:[a-z+]+:)?\/\//.test(href)) {
+                link.href = path_to_root + href;
+            }
+            // The "index" page is supposed to alias the first chapter in the book.
+            if (link.href === current_page || (i === 0 && path_to_root === "" && current_page.endsWith("/index.html"))) {
+                link.classList.add("active");
+                var parent = link.parentElement;
+                if (parent && parent.classList.contains("chapter-item")) {
+                    parent.classList.add("expanded");
+                }
+                while (parent) {
+                    if (parent.tagName === "LI" && parent.previousElementSibling) {
+                        if (parent.previousElementSibling.classList.contains("chapter-item")) {
+                            parent.previousElementSibling.classList.add("expanded");
+                        }
+                    }
+                    parent = parent.parentElement;
+                }
+            }
+        }
+        // Track and set sidebar scroll position
+        this.addEventListener('click', function(e) {
+            if (e.target.tagName === 'A') {
+                sessionStorage.setItem('sidebar-scroll', this.scrollTop);
+            }
+        }, { passive: true });
+        var sidebarScrollTop = sessionStorage.getItem('sidebar-scroll');
+        sessionStorage.removeItem('sidebar-scroll');
+        if (sidebarScrollTop) {
+            // preserve sidebar scroll position when navigating via links within sidebar
+            this.scrollTop = sidebarScrollTop;
+        } else {
+            // scroll sidebar to current active section when navigating via "next/previous chapter" buttons
+            var activeSection = document.querySelector('#sidebar .active');
+            if (activeSection) {
+                activeSection.scrollIntoView({ block: 'center' });
+            }
+        }
+        // Toggle buttons
+        var sidebarAnchorToggles = document.querySelectorAll('#sidebar a.toggle');
+        function toggleSection(ev) {
+            ev.currentTarget.parentElement.classList.toggle('expanded');
+        }
+        Array.from(sidebarAnchorToggles).forEach(function (el) {
+            el.addEventListener('click', toggleSection);
+        });
+    }
+}
+window.customElements.define("mdbook-sidebar-scrollbox", MDBookSidebarScrollbox);
--- a/src/theme/tomorrow-night.css
+++ b/src/theme/tomorrow-night.css
@@ -11,6 +11,7 @@
 /* Tomorrow Red */
 .hljs-variable,
 .hljs-attribute,
+.hljs-attr,
 .hljs-tag,
 .hljs-regexp,
 .ruby .hljs-constant,
@@ -54,6 +55,7 @@

 /* Tomorrow Aqua */
 .hljs-title,
+.hljs-section,
 .css .hljs-hexcolor {
  color: #8abeb7;
 }
--- a/src/utils/fs.rs
+++ b/src/utils/fs.rs
@@ -1,6 +1,5 @@
 use crate::errors::*;
 use log::{debug, trace};
-use std::convert::Into;
 use std::fs::{self, File};
 use std::io::Write;
 use std::path::{Component, Path, PathBuf};
@@ -73,14 +72,12 @@ pub fn create_file(path: &Path) -> Result<File> {

 /// Removes all the content of a directory but not the directory itself
 pub fn remove_dir_content(dir: &Path) -> Result<()> {
-    for item in fs::read_dir(dir)? {
-        if let Ok(item) = item {
-            let item = item.path();
-            if item.is_dir() {
-                fs::remove_dir_all(item)?;
-            } else {
-                fs::remove_file(item)?;
-            }
+    for item in fs::read_dir(dir)?.flatten() {
+        let item = item.path();
+        if item.is_dir() {
+            fs::remove_dir_all(item)?;
+        } else {
+            fs::remove_file(item)?;
        }
    }
    Ok(())
@@ -109,77 +106,102 @@ pub fn copy_files_except_ext(
    }

    for entry in fs::read_dir(from)? {
-        let entry = entry?;
+        let entry = entry?.path();
        let metadata = entry
-            .path()
            .metadata()
-            .with_context(|| format!("Failed to read {:?}", entry.path()))?;
+            .with_context(|| format!("Failed to read {entry:?}"))?;
+
+        let entry_file_name = entry.file_name().unwrap();
+        let target_file_path = to.join(entry_file_name);

        // If the entry is a dir and the recursive option is enabled, call itself
        if metadata.is_dir() && recursive {
-            if entry.path() == to.to_path_buf() {
+            if entry == to.as_os_str() {
                continue;
            }

            if let Some(avoid) = avoid_dir {
-                if entry.path() == *avoid {
+                if entry == *avoid {
                    continue;
                }
            }

            // check if output dir already exists
-            if !to.join(entry.file_name()).exists() {
-                fs::create_dir(&to.join(entry.file_name()))?;
+            if !target_file_path.exists() {
+                fs::create_dir(&target_file_path)?;
            }

-            copy_files_except_ext(
-                &from.join(entry.file_name()),
-                &to.join(entry.file_name()),
-                true,
-                avoid_dir,
-                ext_blacklist,
-            )?;
+            copy_files_except_ext(&entry, &target_file_path, true, avoid_dir, ext_blacklist)?;
        } else if metadata.is_file() {
            // Check if it is in the blacklist
-            if let Some(ext) = entry.path().extension() {
+            if let Some(ext) = entry.extension() {
                if ext_blacklist.contains(&ext.to_str().unwrap()) {
                    continue;
                }
            }
-            debug!(
-                "creating path for file: {:?}",
-                &to.join(
-                    entry
-                        .path()
-                        .file_name()
-                        .expect("a file should have a file name...")
-                )
-            );
-
-            debug!(
-                "Copying {:?} to {:?}",
-                entry.path(),
-                &to.join(
-                    entry
-                        .path()
-                        .file_name()
-                        .expect("a file should have a file name...")
-                )
-            );
-            fs::copy(
-                entry.path(),
-                &to.join(
-                    entry
-                        .path()
-                        .file_name()
-                        .expect("a file should have a file name..."),
-                ),
-            )?;
+            debug!("Copying {entry:?} to {target_file_path:?}");
+            copy(&entry, &target_file_path)?;
        }
    }
    Ok(())
 }

+/// Copies a file.
+fn copy<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> Result<()> {
+    let from = from.as_ref();
+    let to = to.as_ref();
+    return copy_inner(from, to)
+        .with_context(|| format!("failed to copy `{}` to `{}`", from.display(), to.display()));
+
+    // This is a workaround for an issue with the macOS file watcher.
+    // Rust's `std::fs::copy` function uses `fclonefileat`, which creates
+    // clones on APFS. Unfortunately fs events seem to trigger on both
+    // sides of the clone, and there doesn't seem to be a way to differentiate
+    // which side it is.
+    // https://github.com/notify-rs/notify/issues/465#issuecomment-1657261035
+    // contains more information.
+    //
+    // This is essentially a copy of the simple copy code path in Rust's
+    // standard library.
+    #[cfg(target_os = "macos")]
+    fn copy_inner(from: &Path, to: &Path) -> Result<()> {
+        use std::fs::OpenOptions;
+        use std::os::unix::fs::{OpenOptionsExt, PermissionsExt};
+
+        let mut reader = File::open(from)?;
+        let metadata = reader.metadata()?;
+        if !metadata.is_file() {
+            anyhow::bail!(
+                "expected a file, `{}` appears to be {:?}",
+                from.display(),
+                metadata.file_type()
+            );
+        }
+        let perm = metadata.permissions();
+        let mut writer = OpenOptions::new()
+            .mode(perm.mode())
+            .write(true)
+            .create(true)
+            .truncate(true)
+            .open(to)?;
+        let writer_metadata = writer.metadata()?;
+        if writer_metadata.is_file() {
+            // Set the correct file permissions, in case the file already existed.
+            // Don't set the permissions on already existing non-files like
+            // pipes/FIFOs or device nodes.
+            writer.set_permissions(perm)?;
+        }
+        std::io::copy(&mut reader, &mut writer)?;
+        Ok(())
+    }
+
+    #[cfg(not(target_os = "macos"))]
+    fn copy_inner(from: &Path, to: &Path) -> Result<()> {
+        fs::copy(from, to)?;
+        Ok(())
+    }
+}
+
 pub fn get_404_output_file(input_404: &Option<String>) -> String {
    input_404
        .as_ref()
@@ -206,47 +228,47 @@ mod tests {
    fn copy_files_except_ext_test() {
        let tmp = match tempfile::TempDir::new() {
            Ok(t) => t,
-            Err(e) => panic!("Could not create a temp dir: {}", e),
+            Err(e) => panic!("Could not create a temp dir: {e}"),
        };

        // Create a couple of files
        if let Err(err) = fs::File::create(tmp.path().join("file.txt")) {
-            panic!("Could not create file.txt: {}", err);
+            panic!("Could not create file.txt: {err}");
        }
        if let Err(err) = fs::File::create(tmp.path().join("file.md")) {
-            panic!("Could not create file.md: {}", err);
+            panic!("Could not create file.md: {err}");
        }
        if let Err(err) = fs::File::create(tmp.path().join("file.png")) {
-            panic!("Could not create file.png: {}", err);
+            panic!("Could not create file.png: {err}");
        }
        if let Err(err) = fs::create_dir(tmp.path().join("sub_dir")) {
-            panic!("Could not create sub_dir: {}", err);
+            panic!("Could not create sub_dir: {err}");
        }
        if let Err(err) = fs::File::create(tmp.path().join("sub_dir/file.png")) {
-            panic!("Could not create sub_dir/file.png: {}", err);
+            panic!("Could not create sub_dir/file.png: {err}");
        }
        if let Err(err) = fs::create_dir(tmp.path().join("sub_dir_exists")) {
-            panic!("Could not create sub_dir_exists: {}", err);
+            panic!("Could not create sub_dir_exists: {err}");
        }
        if let Err(err) = fs::File::create(tmp.path().join("sub_dir_exists/file.txt")) {
-            panic!("Could not create sub_dir_exists/file.txt: {}", err);
+            panic!("Could not create sub_dir_exists/file.txt: {err}");
        }
        if let Err(err) = symlink(tmp.path().join("file.png"), tmp.path().join("symlink.png")) {
-            panic!("Could not symlink file.png: {}", err);
+            panic!("Could not symlink file.png: {err}");
        }

        // Create output dir
        if let Err(err) = fs::create_dir(tmp.path().join("output")) {
-            panic!("Could not create output: {}", err);
+            panic!("Could not create output: {err}");
        }
        if let Err(err) = fs::create_dir(tmp.path().join("output/sub_dir_exists")) {
-            panic!("Could not create output/sub_dir_exists: {}", err);
+            panic!("Could not create output/sub_dir_exists: {err}");
        }

        if let Err(e) =
            copy_files_except_ext(tmp.path(), &tmp.path().join("output"), true, None, &["md"])
        {
-            panic!("Error while executing the function:\n{:?}", e);
+            panic!("Error while executing the function:\n{e:?}");
        }

        // Check if the correct files where created
--- a/src/utils/mod.rs
+++ b/src/utils/mod.rs
@@ -6,7 +6,7 @@ pub(crate) mod toml_ext;
 use crate::errors::Error;
 use log::error;
 use once_cell::sync::Lazy;
-use pulldown_cmark::{html, CodeBlockKind, CowStr, Event, Options, Parser, Tag};
+use pulldown_cmark::{html, CodeBlockKind, CowStr, Event, Options, Parser, Tag, TagEnd};
 use regex::Regex;

 use std::borrow::Cow;
@@ -77,7 +77,7 @@ pub fn unique_id_from_content(content: &str, id_counter: &mut HashMap<String, us
    let id_count = id_counter.entry(id.clone()).or_insert(0);
    let unique_id = match *id_count {
        0 => id,
-        id_count => format!("{}-{}", id, id_count),
+        id_count => format!("{id}-{id_count}"),
    };
    *id_count += 1;
    unique_id
@@ -105,7 +105,7 @@ fn adjust_links<'a>(event: Event<'a>, path: Option<&Path>) -> Event<'a> {
                if base.ends_with(".md") {
                    base.replace_range(base.len() - 3.., ".html");
                }
-                return format!("{}{}", base, dest).into();
+                return format!("{base}{dest}").into();
            } else {
                return dest;
            }
@@ -121,7 +121,7 @@ fn adjust_links<'a>(event: Event<'a>, path: Option<&Path>) -> Event<'a> {
                    .to_str()
                    .expect("utf-8 paths only");
                if !base.is_empty() {
-                    write!(fixed_link, "{}/", base).unwrap();
+                    write!(fixed_link, "{base}/").unwrap();
                }
            }

@@ -161,38 +161,59 @@ fn adjust_links<'a>(event: Event<'a>, path: Option<&Path>) -> Event<'a> {
    }

    match event {
-        Event::Start(Tag::Link(link_type, dest, title)) => {
-            Event::Start(Tag::Link(link_type, fix(dest, path), title))
-        }
-        Event::Start(Tag::Image(link_type, dest, title)) => {
-            Event::Start(Tag::Image(link_type, fix(dest, path), title))
-        }
+        Event::Start(Tag::Link {
+            link_type,
+            dest_url,
+            title,
+            id,
+        }) => Event::Start(Tag::Link {
+            link_type,
+            dest_url: fix(dest_url, path),
+            title,
+            id,
+        }),
+        Event::Start(Tag::Image {
+            link_type,
+            dest_url,
+            title,
+            id,
+        }) => Event::Start(Tag::Image {
+            link_type,
+            dest_url: fix(dest_url, path),
+            title,
+            id,
+        }),
        Event::Html(html) => Event::Html(fix_html(html, path)),
+        Event::InlineHtml(html) => Event::InlineHtml(fix_html(html, path)),
        _ => event,
    }
 }

 /// Wrapper around the pulldown-cmark parser for rendering markdown to HTML.
-pub fn render_markdown(text: &str, curly_quotes: bool) -> String {
-    render_markdown_with_path(text, curly_quotes, None)
+pub fn render_markdown(text: &str, smart_punctuation: bool) -> String {
+    render_markdown_with_path(text, smart_punctuation, None)
 }

-pub fn new_cmark_parser(text: &str, curly_quotes: bool) -> Parser<'_, '_> {
+pub fn new_cmark_parser(text: &str, smart_punctuation: bool) -> Parser<'_> {
    let mut opts = Options::empty();
    opts.insert(Options::ENABLE_TABLES);
    opts.insert(Options::ENABLE_FOOTNOTES);
    opts.insert(Options::ENABLE_STRIKETHROUGH);
    opts.insert(Options::ENABLE_TASKLISTS);
    opts.insert(Options::ENABLE_HEADING_ATTRIBUTES);
-    if curly_quotes {
+    if smart_punctuation {
        opts.insert(Options::ENABLE_SMART_PUNCTUATION);
    }
    Parser::new_ext(text, opts)
 }

-pub fn render_markdown_with_path(text: &str, curly_quotes: bool, path: Option<&Path>) -> String {
+pub fn render_markdown_with_path(
+    text: &str,
+    smart_punctuation: bool,
+    path: Option<&Path>,
+) -> String {
    let mut s = String::with_capacity(text.len() * 3 / 2);
-    let p = new_cmark_parser(text, curly_quotes);
+    let p = new_cmark_parser(text, smart_punctuation);
    let events = p
        .map(clean_codeblock_headers)
        .map(|event| adjust_links(event, path))
@@ -212,7 +233,7 @@ fn wrap_tables(event: Event<'_>) -> (Option<Event<'_>>, Option<Event<'_>>) {
            Some(Event::Html(r#"<div class="table-wrapper">"#.into())),
            Some(event),
        ),
-        Event::End(Tag::Table(_)) => (Some(event), Some(Event::Html(r#"</div>"#.into()))),
+        Event::End(TagEnd::Table) => (Some(event), Some(Event::Html(r#"</div>"#.into()))),
        _ => (Some(event), None),
    }
 }
@@ -244,6 +265,25 @@ pub fn log_backtrace(e: &Error) {
    }
 }

+pub(crate) fn special_escape(mut s: &str) -> String {
+    let mut escaped = String::with_capacity(s.len());
+    let needs_escape: &[char] = &['<', '>', '\'', '\\', '&'];
+    while let Some(next) = s.find(needs_escape) {
+        escaped.push_str(&s[..next]);
+        match s.as_bytes()[next] {
+            b'<' => escaped.push_str("&lt;"),
+            b'>' => escaped.push_str("&gt;"),
+            b'\'' => escaped.push_str("&#39;"),
+            b'\\' => escaped.push_str("&#92;"),
+            b'&' => escaped.push_str("&amp;"),
+            _ => unreachable!(),
+        }
+        s = &s[next + 1..];
+    }
+    escaped.push_str(s);
+    escaped
+}
+
 pub(crate) fn bracket_escape(mut s: &str) -> String {
    let mut escaped = String::with_capacity(s.len());
    let needs_escape: &[char] = &['<', '>'];
@@ -262,7 +302,7 @@ pub(crate) fn bracket_escape(mut s: &str) -> String {

 #[cfg(test)]
 mod tests {
-    use super::bracket_escape;
+    use super::{bracket_escape, special_escape};

    mod render_markdown {
        use super::super::render_markdown;
@@ -485,5 +525,20 @@ more text with spaces
        assert_eq!(bracket_escape("<>"), "&lt;&gt;");
        assert_eq!(bracket_escape("<test>"), "&lt;test&gt;");
        assert_eq!(bracket_escape("a<test>b"), "a&lt;test&gt;b");
+        assert_eq!(bracket_escape("'"), "'");
+        assert_eq!(bracket_escape("\\"), "\\");
+    }
+
+    #[test]
+    fn escaped_special() {
+        assert_eq!(special_escape(""), "");
+        assert_eq!(special_escape("<"), "&lt;");
+        assert_eq!(special_escape(">"), "&gt;");
+        assert_eq!(special_escape("<>"), "&lt;&gt;");
+        assert_eq!(special_escape("<test>"), "&lt;test&gt;");
+        assert_eq!(special_escape("a<test>b"), "a&lt;test&gt;b");
+        assert_eq!(special_escape("'"), "&#39;");
+        assert_eq!(special_escape("\\"), "&#92;");
+        assert_eq!(special_escape("&"), "&amp;");
    }
 }
--- a/test_book/src/SUMMARY.md
+++ b/test_book/src/SUMMARY.md
@@ -22,6 +22,7 @@
  - [Tables](individual/table.md)
  - [Tasks](individual/task.md)
  - [Strikethrough](individual/strikethrough.md)
+  - [MathJax](individual/mathjax.md)
  - [Mixed](individual/mixed.md)
 - [Languages](languages/README.md)
  - [Syntax Highlight](languages/highlight.md)
--- a/test_book/src/individual/code.md
+++ b/test_book/src/individual/code.md
@@ -10,7 +10,9 @@ This is a codeblock

 ---

-This line contains `inline code`
+This line contains `inline code` mixed with some other stuff. (LTR)
+
+ושורה זו מכילה `inline code` אבל עם טקסט בשפה שנכתבת מימין לשמאל. (RTL)

 ---

--- a/test_book/src/individual/mathjax.md
+++ b/test_book/src/individual/mathjax.md
@@ -0,0 +1,42 @@
+# MathJax
+
+Fourier Transform
+
+\\[
+\begin{aligned}
+f(x) &= \int_{-\infty}^{\infty}F(s)(-1)^{ 2xs}ds \\\\
+F(s) &= \int_{-\infty}^{\infty}f(x)(-1)^{-2xs}dx
+\end{aligned}
+\\]
+
+The kernel can also be written as \\(e^{2i\pi xs}\\) which is more frequently used in literature.
+
+> Proof that \\(e^{ix} = \cos x + i\sin x\\) a.k.a Euler's Formula:
+>
+> \\(
+\begin{aligned}
+  e^x &= \sum_{n=0}^\infty \frac{x^n}{n!} \implies e^{ix} = \sum_{n=0}^\infty \frac{(ix)^n}{n!} \\\\
+  \cos x &= \sum_{m=0}^\infty \frac{(-1)^m x^{2m}}{(2m)!} = \sum_{m=0}^\infty \frac{(ix)^{2m}}{(2m)!} \\\\
+  \sin x &= \sum_{s=0}^\infty \frac{(-1)^s x^{2s+1}}{(2s+1)!} = \sum_{s=0}^\infty \frac{(ix)^{2s+1}}{i(2s+1)!} \\\\
+  \cos x + i\sin x &= \sum_{l=0}^\infty \frac{(ix)^{2l}}{(2l)!} + \sum_{s=0}^\infty \frac{(ix)^{2s+1}}{(2s+1)!} = \sum_{n=0}^\infty \frac{(ix)^{n}}{n!} \\\\
+         &= e^{ix}
+\end{aligned}
+\\)
+>
+
+
+Pauli Matrices
+
+\\[
+\begin{aligned}
+  \sigma_x &= \begin{pmatrix}
+  1 & 0 \\\\ 0 & 1
+  \end{pmatrix} \\\\
+  \sigma_y &= \begin{pmatrix}
+  0 & -i \\\\ i & 0
+  \end{pmatrix} \\\\
+  \sigma_z &= \begin{pmatrix}
+  1 & 0 \\\\ 0 & -1
+  \end{pmatrix}
+\end{aligned}
+\\]
--- a/test_book/src/languages/README.md
+++ b/test_book/src/languages/README.md
@@ -27,6 +27,8 @@ This Currently contains following languages
 - makefile
 - markdown
 - nginx
+- nim
+- nix
 - objectivec
 - perl
 - php
--- a/test_book/src/languages/highlight.md
+++ b/test_book/src/languages/highlight.md
@@ -529,6 +529,26 @@ http {
 var doors {.compileTime.}: array[1..numDoors, bool]

 proc calcDoors(): string =
+  for pass in 1..numDoors:
+    for door in countup(pass, numDoors, pass):
+      doors[door] = not doors[door]
+  for door in 1..numDoors:
+    result.add("Door $1 is $2.\n" % [$door, if doors[door]: "open" else: "closed"])
+
+const outputString: string = calcDoors()
+
+echo outputString
+```
+
+## objectivec
+
+```objectivec
+#import <Foundation/Foundation.h>
+
+int main(int argc, const char * argv[]) {
+    @mylak {
+        NSLog(@"Hello World!");
+    }
    return 0;
 }

@@ -543,6 +563,15 @@ int main(int argc, const char * argv[]) {
 "Hello " + world
 ```

+## perl
+
+```perl
+print "Hello World!\n";
+```
+
+## php
+
+```php
 <?php
 echo "Hello World!";
 ?>
--- a/tests/alternative_backends.rs
+++ b/tests/alternative_backends.rs
@@ -39,29 +39,27 @@ fn alternate_backend_with_arguments() {
    md.build().unwrap();
 }

-/// Get a command which will pipe `stdin` to the provided file.
-#[cfg(not(windows))]
-fn tee_command<P: AsRef<Path>>(out_file: P) -> String {
-    let out_file = out_file.as_ref();
-
-    if cfg!(windows) {
-        format!("cmd.exe /c \"type > {}\"", out_file.display())
-    } else {
-        format!("tee {}", out_file.display())
-    }
-}
-
 #[test]
-#[cfg(not(windows))]
 fn backends_receive_render_context_via_stdin() {
    use mdbook::renderer::RenderContext;
    use std::fs::File;

-    let temp = TempFileBuilder::new().prefix("output").tempdir().unwrap();
-    let out_file = temp.path().join("out.txt");
-    let cmd = tee_command(&out_file);
+    let (md, temp) = dummy_book_with_backend("cat-to-file", "renderers/myrenderer", false);

-    let (md, _temp) = dummy_book_with_backend("cat-to-file", &cmd, false);
+    let renderers = temp.path().join("renderers");
+    fs::create_dir(&renderers).unwrap();
+    rust_exe(
+        &renderers,
+        "myrenderer",
+        r#"fn main() {
+            use std::io::Read;
+            let mut s = String::new();
+            std::io::stdin().read_to_string(&mut s).unwrap();
+            std::fs::write("out.txt", s).unwrap();
+        }"#,
+    );
+
+    let out_file = temp.path().join("book/out.txt");

    assert!(!out_file.exists());
    md.build().unwrap();
@@ -119,13 +117,11 @@ fn dummy_book_with_backend(

    let mut config = Config::default();
    config
-        .set(format!("output.{}.command", name), command)
+        .set(format!("output.{name}.command"), command)
        .unwrap();

    if backend_is_optional {
-        config
-            .set(format!("output.{}.optional", name), true)
-            .unwrap();
+        config.set(format!("output.{name}.optional"), true).unwrap();
    }

    let md = MDBook::init(temp.path())
--- a/tests/cli/init.rs
+++ b/tests/cli/init.rs
@@ -22,3 +22,26 @@ fn base_mdbook_init_can_skip_confirmation_prompts() {

    assert!(!temp.path().join(".gitignore").exists());
 }
+
+/// Run `mdbook init` with `--title` without git config.
+///
+/// Regression test for https://github.com/rust-lang/mdBook/issues/2485
+#[test]
+fn no_git_config_with_title() {
+    let temp = DummyBook::new().build().unwrap();
+
+    // doesn't exist before
+    assert!(!temp.path().join("book").exists());
+
+    let mut cmd = mdbook_cmd();
+    cmd.args(["init", "--title", "Example title"])
+        .current_dir(temp.path())
+        .env("GIT_CONFIG_GLOBAL", "")
+        .env("GIT_CONFIG_NOSYSTEM", "1");
+    cmd.assert()
+        .success()
+        .stdout(predicates::str::contains("\nAll done, no errors...\n"));
+
+    let config = Config::from_disk(temp.path().join("book.toml")).unwrap();
+    assert_eq!(config.book.title.as_deref(), Some("Example title"));
+}
--- a/tests/dummy_book/src/conclusion.md
+++ b/tests/dummy_book/src/conclusion.md
@@ -18,3 +18,7 @@ css looks, like this {
 }
 */
 </style>
+
+Sneaky inline event <script>alert("inline");</script>.
+
+But regular <b>inline</b> is indexed.
--- a/tests/gui/runner.rs
+++ b/tests/gui/runner.rs
@@ -0,0 +1,87 @@
+use std::env::current_dir;
+use std::fs::{read_to_string, remove_dir_all};
+use std::process::Command;
+
+fn get_available_browser_ui_test_version_inner(global: bool) -> Option<String> {
+    let mut command = Command::new("npm");
+    command
+        .arg("list")
+        .arg("--parseable")
+        .arg("--long")
+        .arg("--depth=0");
+    if global {
+        command.arg("--global");
+    }
+    let stdout = command.output().expect("`npm` command not found").stdout;
+    let lines = String::from_utf8_lossy(&stdout);
+    lines
+        .lines()
+        .find_map(|l| l.split(':').nth(1)?.strip_prefix("browser-ui-test@"))
+        .map(std::borrow::ToOwned::to_owned)
+}
+
+fn get_available_browser_ui_test_version() -> Option<String> {
+    get_available_browser_ui_test_version_inner(false)
+        .or_else(|| get_available_browser_ui_test_version_inner(true))
+}
+
+fn expected_browser_ui_test_version() -> String {
+    let content = read_to_string(".github/workflows/main.yml")
+        .expect("failed to read `.github/workflows/main.yml`");
+    for line in content.lines() {
+        let line = line.trim();
+        if let Some(version) = line.strip_prefix("BROWSER_UI_TEST_VERSION:") {
+            return version.trim().replace('\'', "");
+        }
+    }
+    panic!("failed to retrieved `browser-ui-test` version");
+}
+
+fn main() {
+    let browser_ui_test_version = expected_browser_ui_test_version();
+    match get_available_browser_ui_test_version() {
+        Some(version) => {
+            if version != browser_ui_test_version {
+                eprintln!(
+                    "⚠️ Installed version of browser-ui-test (`{version}`) is different than the \
+                     one used in the CI (`{browser_ui_test_version}`) You can install this version \
+                     using `npm update browser-ui-test` or by using `npm install browser-ui-test\
+                     @{browser_ui_test_version}`",
+                );
+            }
+        }
+        None => {
+            panic!(
+                "`browser-ui-test` is not installed. You can install this package using `npm \
+                 update browser-ui-test` or by using `npm install browser-ui-test\
+                 @{browser_ui_test_version}`",
+            );
+        }
+    }
+
+    let current_dir = current_dir().expect("failed to retrieve current directory");
+    let test_book = current_dir.join("test_book");
+
+    // Result doesn't matter.
+    let _ = remove_dir_all(test_book.join("book"));
+
+    let mut cmd = Command::new("cargo");
+    cmd.arg("run").arg("build").arg(&test_book);
+    // Then we run the GUI tests on it.
+    assert!(cmd.status().is_ok_and(|status| status.success()));
+
+    let book_dir = format!("file://{}", current_dir.join("test_book/book/").display());
+
+    let mut command = Command::new("npx");
+    command
+        .arg("browser-ui-test")
+        .args(["--variable", "DOC_PATH", book_dir.as_str()])
+        .args(["--test-folder", "tests/gui"]);
+    if std::env::args().any(|arg| arg == "--disable-headless-test") {
+        command.arg("--no-headless");
+    }
+
+    // Then we run the GUI tests on it.
+    let status = command.status().expect("failed to get command output");
+    assert!(status.success(), "{status:?}");
+}
--- a/tests/gui/sidebar-nojs.goml
+++ b/tests/gui/sidebar-nojs.goml
@@ -0,0 +1,16 @@
+// This GUI test checks that the sidebar takes the whole height when it's inside
+// an iframe (because of JS disabled).
+// Regression test for <https://github.com/rust-lang/mdBook/issues/2528>.
+
+// We disable the requests checks because `searchindex.json` will always fail
+// locally.
+fail-on-request-error: false
+// We disable javascript
+javascript: false
+go-to: |DOC_PATH| + "index.html"
+store-value: (height, 1000)
+set-window-size: (1000, |height|)
+
+within-iframe: (".sidebar-iframe-outer", block {
+    assert-size: (" body", {"height": |height|})
+})
--- a/tests/gui/sidebar.goml
+++ b/tests/gui/sidebar.goml
@@ -0,0 +1,59 @@
+// This GUI test checks sidebar hide/show and also its behaviour on smaller
+// width.
+
+// We disable the requests checks because `searchindex.json` will always fail
+// locally.
+fail-on-request-error: false
+go-to: |DOC_PATH| + "index.html"
+set-window-size: (1100, 600)
+// Need to reload for the new size to be taken account by the JS.
+reload:
+
+store-value: (content_indent, 308)
+
+define-function: (
+    "hide-sidebar",
+    [],
+    block {
+        // The content should be "moved" to the right because of the sidebar.
+        assert-css: ("#sidebar", {"transform": "none"})
+        assert-position: ("#page-wrapper", {"x": |content_indent|})
+
+        // We now hide the sidebar.
+        click: "#sidebar-toggle"
+        wait-for: "body.sidebar-hidden"
+        // `transform` is 0.3s so we need to wait a bit (0.5s) to ensure the animation is done.
+        wait-for: 5000
+        assert-css-false: ("#sidebar", {"transform": "none"})
+        // The page content should now be on the left.
+        assert-position: ("#page-wrapper", {"x": 0})
+    },
+)
+
+define-function: (
+    "show-sidebar",
+    [],
+    block {
+        // The page content should be on the left and the sidebar "moved out".
+        assert-css: ("#sidebar", {"transform": "matrix(1, 0, 0, 1, -308, 0)"})
+        assert-position: ("#page-wrapper", {"x": 0})
+
+        // We expand the sidebar.
+        click: "#sidebar-toggle"
+        wait-for: "body.sidebar-visible"
+        // `transform` is 0.3s so we need to wait a bit (0.5s) to ensure the animation is done.
+        wait-for: 5000
+        assert-css-false: ("#sidebar", {"transform": "matrix(1, 0, 0, 1, -308, 0)"})
+        // The page content should be moved to the right.
+        assert-position: ("#page-wrapper", {"x": |content_indent|})
+    },
+)
+
+call-function: ("hide-sidebar", {})
+call-function: ("show-sidebar", {})
+
+// We now test on smaller width to ensure that the sidebar is collapsed by default.
+set-window-size: (900, 600)
+reload:
+call-function: ("show-sidebar", {})
+call-function: ("hide-sidebar", {})
--- a/tests/init.rs
+++ b/tests/init.rs
@@ -23,7 +23,7 @@ fn base_mdbook_init_should_create_default_content() {
    for file in &created_files {
        let target = temp.path().join(file);
        println!("{}", target.display());
-        assert!(target.exists(), "{} doesn't exist", file);
+        assert!(target.exists(), "{file} doesn't exist");
    }

    let contents = fs::read_to_string(temp.path().join("book.toml")).unwrap();
@@ -59,7 +59,7 @@ fn run_mdbook_init_should_create_content_from_summary() {
    for file in &created_files {
        let target = src_dir.join(file);
        println!("{}", target.display());
-        assert!(target.exists(), "{} doesn't exist", file);
+        assert!(target.exists(), "{file} doesn't exist");
    }
 }

@@ -73,8 +73,7 @@ fn run_mdbook_init_with_custom_book_and_src_locations() {
    for file in &created_files {
        assert!(
            !temp.path().join(file).exists(),
-            "{} shouldn't exist yet!",
-            file
+            "{file} shouldn't exist yet!"
        );
    }

@@ -88,8 +87,7 @@ fn run_mdbook_init_with_custom_book_and_src_locations() {
        let target = temp.path().join(file);
        assert!(
            target.exists(),
-            "{} should have been created by `mdbook init`",
-            file
+            "{file} should have been created by `mdbook init`"
        );
    }

--- a/tests/rendered_output.rs
+++ b/tests/rendered_output.rs
@@ -3,13 +3,14 @@ mod dummy_book;
 use crate::dummy_book::{assert_contains_strings, assert_doesnt_contain_strings, DummyBook};

 use anyhow::Context;
+use mdbook::book::Chapter;
 use mdbook::config::Config;
 use mdbook::errors::*;
 use mdbook::utils::fs::write_file;
-use mdbook::MDBook;
+use mdbook::{BookItem, MDBook};
 use pretty_assertions::assert_eq;
 use select::document::Document;
-use select::predicate::{Class, Name, Predicate};
+use select::predicate::{Attr, Class, Name, Predicate};
 use std::collections::HashMap;
 use std::ffi::OsStr;
 use std::fs;
@@ -61,28 +62,6 @@ fn by_default_mdbook_generates_rendered_content_in_the_book_directory() {
    assert!(index_file.exists());
 }

-#[test]
-fn make_sure_bottom_level_files_contain_links_to_chapters() {
-    let temp = DummyBook::new().build().unwrap();
-    let md = MDBook::load(temp.path()).unwrap();
-    md.build().unwrap();
-
-    let dest = temp.path().join("book");
-    let links = vec![
-        r#"href="intro.html""#,
-        r#"href="first/index.html""#,
-        r#"href="first/nested.html""#,
-        r#"href="second.html""#,
-        r#"href="conclusion.html""#,
-    ];
-
-    let files_in_bottom_dir = vec!["index.html", "intro.html", "second.html", "conclusion.html"];
-
-    for filename in files_in_bottom_dir {
-        assert_contains_strings(dest.join(filename), &links);
-    }
-}
-
 #[test]
 fn check_correct_cross_links_in_nested_dir() {
    let temp = DummyBook::new().build().unwrap();
@@ -90,19 +69,6 @@ fn check_correct_cross_links_in_nested_dir() {
    md.build().unwrap();

    let first = temp.path().join("book").join("first");
-    let links = vec![
-        r#"href="../intro.html""#,
-        r#"href="../first/index.html""#,
-        r#"href="../first/nested.html""#,
-        r#"href="../second.html""#,
-        r#"href="../conclusion.html""#,
-    ];
-
-    let files_in_nested_dir = vec!["index.html", "nested.html"];
-
-    for filename in files_in_nested_dir {
-        assert_contains_strings(first.join(filename), &links);
-    }

    assert_contains_strings(
        first.join("index.html"),
@@ -265,9 +231,9 @@ fn entry_ends_with(entry: &DirEntry, ending: &str) -> bool {
    entry.file_name().to_string_lossy().ends_with(ending)
 }

-/// Read the main page (`book/index.html`) and expose it as a DOM which we
+/// Read the TOC (`book/toc.js`) nested HTML and expose it as a DOM which we
 /// can search with the `select` crate
-fn root_index_html() -> Result<Document> {
+fn toc_js_html() -> Result<Document> {
    let temp = DummyBook::new()
        .build()
        .with_context(|| "Couldn't create the dummy book")?;
@@ -275,15 +241,36 @@ fn root_index_html() -> Result<Document> {
        .build()
        .with_context(|| "Book building failed")?;

-    let index_page = temp.path().join("book").join("index.html");
-    let html = fs::read_to_string(index_page).with_context(|| "Unable to read index.html")?;
+    let toc_path = temp.path().join("book").join("toc.js");
+    let html = fs::read_to_string(toc_path).with_context(|| "Unable to read index.html")?;
+    for line in html.lines() {
+        if let Some(left) = line.strip_prefix("        this.innerHTML = '") {
+            if let Some(html) = left.strip_suffix("';") {
+                return Ok(Document::from(html));
+            }
+        }
+    }
+    panic!("cannot find toc in file")
+}

+/// Read the TOC fallback (`book/toc.html`) HTML and expose it as a DOM which we
+/// can search with the `select` crate
+fn toc_fallback_html() -> Result<Document> {
+    let temp = DummyBook::new()
+        .build()
+        .with_context(|| "Couldn't create the dummy book")?;
+    MDBook::load(temp.path())?
+        .build()
+        .with_context(|| "Book building failed")?;
+
+    let toc_path = temp.path().join("book").join("toc.html");
+    let html = fs::read_to_string(toc_path).with_context(|| "Unable to read index.html")?;
    Ok(Document::from(html.as_str()))
 }

 #[test]
 fn check_second_toc_level() {
-    let doc = root_index_html().unwrap();
+    let doc = toc_js_html().unwrap();
    let mut should_be = Vec::from(TOC_SECOND_LEVEL);
    should_be.sort_unstable();

@@ -305,7 +292,7 @@ fn check_second_toc_level() {

 #[test]
 fn check_first_toc_level() {
-    let doc = root_index_html().unwrap();
+    let doc = toc_js_html().unwrap();
    let mut should_be = Vec::from(TOC_TOP_LEVEL);

    should_be.extend(TOC_SECOND_LEVEL);
@@ -328,7 +315,7 @@ fn check_first_toc_level() {

 #[test]
 fn check_spacers() {
-    let doc = root_index_html().unwrap();
+    let doc = toc_js_html().unwrap();
    let should_be = 2;

    let num_spacers = doc
@@ -337,6 +324,39 @@ fn check_spacers() {
    assert_eq!(num_spacers, should_be);
 }

+// don't use target="_parent" in JS
+#[test]
+fn check_link_target_js() {
+    let doc = toc_js_html().unwrap();
+
+    let num_parent_links = doc
+        .find(
+            Class("chapter")
+                .descendant(Name("li"))
+                .descendant(Name("a").and(Attr("target", "_parent"))),
+        )
+        .count();
+    assert_eq!(num_parent_links, 0);
+}
+
+// don't use target="_parent" in IFRAME
+#[test]
+fn check_link_target_fallback() {
+    let doc = toc_fallback_html().unwrap();
+
+    let num_parent_links = doc
+        .find(
+            Class("chapter")
+                .descendant(Name("li"))
+                .descendant(Name("a").and(Attr("target", "_parent"))),
+        )
+        .count();
+    assert_eq!(
+        num_parent_links,
+        TOC_TOP_LEVEL.len() + TOC_SECOND_LEVEL.len()
+    );
+}
+
 /// Ensure building fails if `create-missing` is false and one of the files does
 /// not exist.
 #[test]
@@ -375,10 +395,7 @@ fn able_to_include_playground_files_in_chapters() {

    let second = temp.path().join("book/second.html");

-    let playground_strings = &[
-        r#"class="playground""#,
-        r#"println!(&quot;Hello World!&quot;);"#,
-    ];
+    let playground_strings = &[r#"class="playground""#, r#"println!("Hello World!");"#];

    assert_contains_strings(&second, playground_strings);
    assert_doesnt_contain_strings(&second, &["{{#playground example.rs}}"]);
@@ -452,18 +469,15 @@ fn by_default_mdbook_use_index_preprocessor_to_convert_readme_to_index() {
    let md = MDBook::load_with_config(temp.path(), cfg).unwrap();
    md.build().unwrap();

-    let first_index = temp.path().join("book").join("first").join("index.html");
+    let first_index = temp.path().join("book").join("toc.js");
    let expected_strings = vec![
-        r#"href="../first/index.html""#,
-        r#"href="../second/index.html""#,
-        "First README",
+        r#"href="first/index.html""#,
+        r#"href="second/index.html""#,
+        "1st README",
+        "2nd README",
    ];
    assert_contains_strings(&first_index, &expected_strings);
-    assert_doesnt_contain_strings(&first_index, &["README.html"]);
-
-    let second_index = temp.path().join("book").join("second").join("index.html");
-    let unexpected_strings = vec!["Second README"];
-    assert_doesnt_contain_strings(second_index, &unexpected_strings);
+    assert_doesnt_contain_strings(&first_index, &["README.html", "Second README"]);
 }

 #[test]
@@ -642,11 +656,11 @@ fn summary_with_markdown_formatting() {
    let md = MDBook::load_with_config(temp.path(), cfg).unwrap();
    md.build().unwrap();

-    let rendered_path = temp.path().join("book/formatted-summary.html");
+    let rendered_path = temp.path().join("book/toc.js");
    assert_contains_strings(
        rendered_path,
        &[
-            r#"<a href="formatted-summary.html" class="active"><strong aria-hidden="true">1.</strong> Italic code *escape* `escape2`</a>"#,
+            r#"<a href="formatted-summary.html"><strong aria-hidden="true">1.</strong> Italic code *escape* `escape2`</a>"#,
            r#"<a href="soft.html"><strong aria-hidden="true">2.</strong> Soft line break</a>"#,
            r#"<a href="escaped-tag.html"><strong aria-hidden="true">3.</strong> &lt;escaped tag&gt;</a>"#,
        ],
@@ -723,6 +737,7 @@ fn failure_on_missing_theme_directory() {
 #[cfg(feature = "search")]
 mod search {
    use crate::dummy_book::DummyBook;
+    use mdbook::utils::fs::write_file;
    use mdbook::MDBook;
    use std::fs::{self, File};
    use std::path::Path;
@@ -745,6 +760,7 @@ mod search {
        let index = read_book_index(temp.path());

        let doc_urls = index["doc_urls"].as_array().unwrap();
+        eprintln!("doc_urls={doc_urls:#?}",);
        let get_doc_ref =
            |url: &str| -> String { doc_urls.iter().position(|s| s == url).unwrap().to_string() };

@@ -774,7 +790,10 @@ mod search {
            docs[&summary]["breadcrumbs"],
            "First Chapter » Includes » Summary"
        );
-        assert_eq!(docs[&conclusion]["body"], "I put &lt;HTML&gt; in here!");
+        // See note about InlineHtml in search.rs. Ideally the `alert()` part
+        // should not be in the index, but we don't have a way to scrub inline
+        // html.
+        assert_eq!(docs[&conclusion]["body"], "I put &lt;HTML&gt; in here! Sneaky inline event alert(\"inline\");. But regular inline is indexed.");
        assert_eq!(
            docs[&no_headers]["breadcrumbs"],
            "First Chapter » No Headers"
@@ -793,6 +812,51 @@ mod search {
        );
    }

+    #[test]
+    fn can_disable_individual_chapters() {
+        let temp = DummyBook::new().build().unwrap();
+        let book_toml = r#"
+            [book]
+            title = "Search Test"
+
+            [output.html.search.chapter]
+            "second" = { enable = false }
+            "first/unicode.md" = { enable = false }
+            "#;
+        write_file(temp.path(), "book.toml", book_toml.as_bytes()).unwrap();
+        let md = MDBook::load(temp.path()).unwrap();
+        md.build().unwrap();
+        let index = read_book_index(temp.path());
+        let doc_urls = index["doc_urls"].as_array().unwrap();
+        let contains = |path| {
+            doc_urls
+                .iter()
+                .any(|p| p.as_str().unwrap().starts_with(path))
+        };
+        assert!(contains("second.html"));
+        assert!(!contains("second/"));
+        assert!(!contains("first/unicode.html"));
+        assert!(contains("first/markdown.html"));
+    }
+
+    #[test]
+    fn chapter_settings_validation_error() {
+        let temp = DummyBook::new().build().unwrap();
+        let book_toml = r#"
+            [book]
+            title = "Search Test"
+
+            [output.html.search.chapter]
+            "does-not-exist" = { enable = false }
+            "#;
+        write_file(temp.path(), "book.toml", book_toml.as_bytes()).unwrap();
+        let md = MDBook::load(temp.path()).unwrap();
+        let err = md.build().unwrap_err();
+        assert!(format!("{err:?}").contains(
+            "[output.html.search.chapter] key `does-not-exist` does not match any chapter paths"
+        ));
+    }
+
    // Setting this to `true` may cause issues with `cargo watch`,
    // since it may not finish writing the fixture before the tests
    // are run again.
@@ -968,3 +1032,21 @@ fn custom_header_attributes() {
    ];
    assert_contains_strings(&contents, summary_strings);
 }
+
+#[test]
+fn with_no_source_path() {
+    // Test for a regression where search would fail if source_path is None.
+    let temp = DummyBook::new().build().unwrap();
+    let mut md = MDBook::load(temp.path()).unwrap();
+    let chapter = Chapter {
+        name: "Sample chapter".to_string(),
+        content: "".to_string(),
+        number: None,
+        sub_items: Vec::new(),
+        path: Some(PathBuf::from("sample.html")),
+        source_path: None,
+        parent_names: Vec::new(),
+    };
+    md.book.sections.push(BookItem::Chapter(chapter));
+    md.build().unwrap();
+}
--- a/tests/searchindex_fixture.json
+++ b/tests/searchindex_fixture.json
@@ -145,7 +145,7 @@
          "title": 1
        },
        "29": {
-          "body": 3,
+          "body": 10,
          "breadcrumbs": 2,
          "title": 1
        },
@@ -319,7 +319,7 @@
          "title": "Some section"
        },
        "29": {
-          "body": "I put &lt;HTML&gt; in here!",
+          "body": "I put &lt;HTML&gt; in here! Sneaky inline event alert(\"inline\");. But regular inline is indexed.",
          "breadcrumbs": "Conclusion » Conclusion",
          "id": "29",
          "title": "Conclusion"
@@ -412,6 +412,54 @@
            },
            "df": 0,
            "docs": {},
+            "l": {
+              "df": 0,
+              "docs": {},
+              "e": {
+                "df": 0,
+                "docs": {},
+                "r": {
+                  "df": 0,
+                  "docs": {},
+                  "t": {
+                    "(": {
+                      "\"": {
+                        "df": 0,
+                        "docs": {},
+                        "i": {
+                          "df": 0,
+                          "docs": {},
+                          "n": {
+                            "df": 0,
+                            "docs": {},
+                            "l": {
+                              "df": 0,
+                              "docs": {},
+                              "i": {
+                                "df": 0,
+                                "docs": {},
+                                "n": {
+                                  "df": 1,
+                                  "docs": {
+                                    "29": {
+                                      "tf": 1.0
+                                    }
+                                  }
+                                }
+                              }
+                            }
+                          }
+                        }
+                      },
+                      "df": 0,
+                      "docs": {}
+                    },
+                    "df": 0,
+                    "docs": {}
+                  }
+                }
+              }
+            },
            "n": {
              "c": {
                "df": 0,
@@ -1212,6 +1260,14 @@
                    "26": {
                      "tf": 1.0
                    }
+                  },
+                  "t": {
+                    "df": 1,
+                    "docs": {
+                      "29": {
+                        "tf": 1.0
+                      }
+                    }
                  }
                }
              }
@@ -1684,10 +1740,13 @@
                  "df": 0,
                  "docs": {},
                  "x": {
-                    "df": 1,
+                    "df": 2,
                    "docs": {
                      "0": {
                        "tf": 1.0
+                      },
+                      "29": {
+                        "tf": 1.0
                      }
                    }
                  }
@@ -1695,6 +1754,22 @@
              },
              "df": 0,
              "docs": {},
+              "l": {
+                "df": 0,
+                "docs": {},
+                "i": {
+                  "df": 0,
+                  "docs": {},
+                  "n": {
+                    "df": 1,
+                    "docs": {
+                      "29": {
+                        "tf": 1.4142135623730951
+                      }
+                    }
+                  }
+                }
+              },
              "s": {
                "df": 0,
                "docs": {},
@@ -2359,6 +2434,30 @@
              },
              "df": 0,
              "docs": {},
+              "g": {
+                "df": 0,
+                "docs": {},
+                "u": {
+                  "df": 0,
+                  "docs": {},
+                  "l": {
+                    "a": {
+                      "df": 0,
+                      "docs": {},
+                      "r": {
+                        "df": 1,
+                        "docs": {
+                          "29": {
+                            "tf": 1.0
+                          }
+                        }
+                      }
+                    },
+                    "df": 0,
+                    "docs": {}
+                  }
+                }
+              },
              "l": {
                "df": 1,
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