Add override input parameter that controls the rustup override behavior

When using this action in multiple matrix jobs in the same workflow, the
generated cache key is the same for all of them, because they all get
the same job ID. This means that all apart from the first job are unable
to save the cache, and subsequent runs might restore the wrong cache.

The `Swatinem/rust-cache` action which we use for caching has a `key`
input which it puts in its cache key. (It doesn't override the key, just
adds to it.) Providing this as an input here will allow us to generate a
unique cache key for each job in the matrix.

.github/dependabot.yml

@@ -0,0 +1,11 @@
+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for all configuration options:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "monthly"

.github/workflows/autotag-releases.yml

@@ -15,11 +15,11 @@ jobs:
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Get version from tag
         id: tag_name
         run: |
-          echo ::set-output name=current_version::${GITHUB_REF#refs/tags/}
+          echo "current_version=${GITHUB_REF#refs/tags/}" >> $GITHUB_OUTPUT
         shell: bash
       - name: Create and push tags
         run: |

.github/workflows/ci.yml

@@ -1,31 +1,106 @@
-
 name: CI
 
 on:
-  push:
+  push: { branches: [main] }
   pull_request:
   schedule: [cron: "40 1 * * *"]
 
 jobs:
   install:
-    name: Rust ${{matrix.rust}}
-    runs-on: ubuntu-latest
+    name: Rust ${{matrix.rust || '(default)'}} (toolchain-file=${{matrix.write-toolchain-file}}) (${{matrix.os}})
+    runs-on: ${{matrix.os}}
     strategy:
       fail-fast: false
+      max-parallel: 5
       matrix:
-        rust: [nightly, beta, stable]
+        os:
+          - ubuntu-latest
+          - windows-latest
+          - macos-latest
+        write-toolchain-file:
+          - false
+          - true
+        rust:
+          # use stable toolchain as default
+          - null
+
+          # Test that the sparse registry check works.
+          # 1.66 and 1.67 don't support stable sparse registry.
+          - "1.66"
+
+          - "nightly"
+          - "beta"
+          - "stable"
     steps:
-      - uses: actions/checkout@v3
-      - uses: ./
-        name: Run actions-rust-lang/setup-rust-toolchain ${{matrix.rust}}
-        id: toolchain
+      - uses: actions/checkout@v4
+
+      # Test toolchain file support
+      - name: Write rust-toolchain.toml
+        if: matrix.write-toolchain-file
+        shell: bash
+        run: |
+          cat <<EOF >>rust-toolchain.toml
+          [toolchain]
+          channel = "nightly-2024-01-10"
+          components = [ "rustfmt", "rustc-dev" ]
+          targets = [ "wasm32-unknown-unknown", "thumbv7m-none-eabi" ]
+          profile = "minimal"
+          EOF
+
+      - id: toolchain
+        name: Run actions-rust-lang/setup-rust-toolchain ${{matrix.rust || 'on toolchain file'}}
+        uses: ./
         with:
           toolchain: ${{matrix.rust}}
+          components: clippy
+
       - name: Check ${{'${{steps.toolchain.outputs.rustc-version}}'}}
         run: echo '${{steps.toolchain.outputs.rustc-version}}'
+
       - name: Check ${{'${{steps.toolchain.outputs.cargo-version}}'}}
         run: echo '${{steps.toolchain.outputs.cargo-version}}'
+
       - name: Check ${{'${{steps.toolchain.outputs.rustup-version}}'}}
         run: echo '${{steps.toolchain.outputs.rustup-version}}'
-      - run: rustc --version && cargo --version
+
+      - name: Check lack of toolchain input or file results in stable
+        if: matrix.write-toolchain-file == false && matrix.rust == null
         shell: bash
+        run: |-
+          rustcv="$(rustc --version)"
+          [[ "$rustcv" != *"nightly"* && "$rustcv" != *"beta"* ]]
+
+      - name: Check toolchain file is being overridden
+        if: matrix.write-toolchain-file
+        shell: bash
+        run: |-
+          rustcv="$(rustc --version)"
+          [[ ! ( "$rustcv" == *"nightly"* && "$rustcv" == *"2024-01-10"* ) ]]
+
+      - shell: bash
+        run: rustc --version && cargo --version
+
+      # Test with creating a small project
+      - run: cargo init . --bin --name ci
+
+      # Add tiny empty crate.
+      # This checks that registry access works.
+      - run: cargo add serde_as
+
+      - run: cargo clippy
+
+  cache:
+    name: Cache
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust
+        uses: ./
+        with:
+          components: clippy
+          cache: true
+          cache-workspaces: |-
+            ./test-workspace
+
+      - run: cargo clippy --manifest-path=./test-workspace/Cargo.toml

.pre-commit-config.yaml

@@ -0,0 +1,18 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.6.0
+    hooks:
+      - id: check-case-conflict
+      - id: check-executables-have-shebangs
+      - id: check-merge-conflict
+      - id: check-json
+      - id: check-yaml
+      - id: end-of-file-fixer
+      - id: trailing-whitespace
+        args: [--markdown-linebreak-ext=md]
+  - repo: https://github.com/python-jsonschema/check-jsonschema
+    rev: 0.29.2
+    hooks:
+      - id: check-dependabot
+      - id: check-github-actions
+      - id: check-github-workflows

CHANGELOG.md

@@ -7,6 +7,183 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+* Add new parameter `cache-directories` that is propagated to `Swatinem/rust-cache` (#44 by @pranc1ngpegasus)
+* Add new parameter `cache-key` that is propagated to `Swatinem/rust-cache` as `key` (#41 by @iainlane)
+* Make rustup toolchain installation more robust in light of planned changes https://github.com/rust-lang/rustup/issues/3635 and https://github.com/rust-lang/rustup/pull/3985
+* Allow installing multiple Rust toolchains by specifying multiple versions in the `toolchain` input parameter.
+* Configure the `rustup override` behavior via the new `override` input. (#38)
+
+## [1.9.0] - 2024-06-08
+
+* Add extra argument `cache-on-failure` and forward it to `Swatinem/rust-cache`. (#39 by @samuelhnrq)  
+    Set the default the value to true.
+    This will result in more caching than previously.
+    This helps when large dependencies are compiled only for testing to fail.
+
+## [1.8.0] - 2024-01-13
+
+* Allow specifying subdirectories for cache.
+* Fix toolchain file overriding.
+
+## [1.7.0] - 2024-01-11
+
+* Allow overriding the toolchain file with explicit `toolchain` input. (#26)
+
+## [1.6.0] - 2023-12-04
+
+### Added
+
+* Allow disabling problem matchers (#27)
+    This can be useful when having a matrix of jobs, that produce the same errors.
+
+## [1.5.0] - 2023-05-29
+
+### Added
+
+* Support installing additional components and targets that are not listed in `rust-toolchain` (#14)
+    Before only the items listed in `rust-toolchain` were installed.
+    Now all the items from the toolchain file are installed and then all the `target`s and `components` that are provided as action inputs.
+    This allows installing extra tools only for CI or simplify testing special targets in CI.
+* Allow skipping the creation of a `RUSTFLAGS` environment variable.
+    Cargos logic for rustflags is complicated, and setting the `RUSTFLAGS` environment variable prevents other ways of working.
+    Provide a new `rustflags` input, which controls the environment variable creation.
+    If the value is set to the empty string, then `RUSTFLAGS` is not created.
+
+    Pre-existing `RUSTFLAGS` variables are never modified by this extension.
+
+## [1.4.4] - 2023-03-18
+
+### Fixed
+
+* Use color aware problem matcher.
+    The problem matcher currently runs against the colored terminal output ([Bug 1](https://github.com/actions/runner/issues/2341), [Bug 2](https://github.com/actions/runner/pull/2430)).
+    The previous matcher was not aware of ANSII color codes and did not work.
+
+## [1.4.3] - 2023-02-21
+
+### Fixed
+
+* Executing the action twice for different toolchains now no longer fails around unstable features #12.
+    If multiple toolchains are installed, the "CARGO_REGISTRIES_CRATES_IO_PROTOCOL" can be downgraded to "git" if any of the installed toolchains require it.
+
+## [1.4.2] - 2023-02-15
+
+### Fixed
+
+* Tweak sparse registry version regex to better work with 1.68 nightly versions.
+* Fix command not found issue
+
+## [1.4.1] - 2023-02-13
+
+### Fixed
+
+* Fixed running on macOS #9 #10
+    The macOS images have an ancient version of bash, but the action relies on "newer" features than 2014.
+    We install bash via brew (already pre-installed) to have a new enough version.
+
+    The CI is extended to also run on Windows and macOS to catch such issues earlier in the future.
+
+    Thanks to @GeorgeHahn for reporting the issue.
+
+## [1.4.0] - 2023-02-13
+
+### Changed
+
+* Only set environment variables, if they are not set before.
+    This allows setting environment variables before using this action and keeping their values.
+* Enable stable sparse registry, except on versions 1.66 and 1.67 where this leads to errors.
+
+## [1.3.7] - 2023-01-31
+
+### Fixed
+
+* Disable the stable access to the sparse registry.
+    Setting the value causes problem on version before stabilization, e.g., 1.67.
+    For example, "cargo add" fails.
+
+## [1.3.6] - 2023-01-31
+
+### Fixed
+
+* The the correct environment variable to enable the sparse registry access.
+    The pull request originally had the wrong value, without `CARGO_` prefix.
+
+## [1.3.5] - 2023-01-21
+
+### Changed
+
+* Use the newly stabilized setting to enable sparse registry access.
+    This speeds up access to the crate registry and is in addition to the unstable nightly env var.
+    <https://github.com/rust-lang/cargo/pull/11224>
+
+## [1.3.4] - 2022-10-15
+
+### Changed
+
+* The last version did not fix all "set-output" commands
+
+## [1.3.3] - 2022-10-13
+
+### Changed
+
+* Switch from set-output to $GITHUB_OUTPUT to avoid warning
+    https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/
+
+## [1.3.2] - 2022-09-15
+
+### Fixed
+
+* Fix setting `$CARGO_HOME` to a valid path, in case rustup is installed from the internet.
+    Thanks to @nahsi for providing the fix.
+
+## [1.3.1] - 2022-08-14
+
+### Changed
+
+* Use the sparse-registry on nightly for faster access to the crate registry on nightly.
+    <https://internals.rust-lang.org/t/call-for-testing-cargo-sparse-registry/16862>
+
+## [1.3.0] - 2022-07-30
+
+### Added
+
+* An option to disable configuring Rust cache.
+    Thanks to @filips123 for the PR.
+
+## [1.2.1] - 2022-07-29
+
+### Fixed
+
+* Set environment variables before invoking the cache action.
+    This ensures restoring and saving are using the same cache key.
+
+## [1.2.0] - 2022-07-21
+
+### Added
+
+* Prefer toolchain definitions in `rust-toolchain` or `rust-toolchain.toml` files ([Toolchain File](https://rust-lang.github.io/rustup/overrides.html#the-toolchain-file)).
+    Other input values are ignored if either file is found.
+
+## [1.1.0] - 2022-07-19
+
+### Added
+
+* Install rustup if not available in the CI environment. (Linux only)
+    The code is taken from this issue: <https://github.com/dtolnay/rust-toolchain/pull/8>
+* Add rustc version output suitable as a cache key.
+    This is based on <https://github.com/dtolnay/rust-toolchain/pull/20> and <https://github.com/dtolnay/rust-toolchain/pull/17>.
+
+### Changed
+
+* Update to `Swatinem/rust-cache@v2`.
+
+## [1.0.2] - 2022-05-02
+
+### Changed
+
+* Enable colored cargo output.
+* Print short backtraces during test failure.
+
 ## [1.0.1] - 2022-04-20
 
 ### Added

README.md

@@ -21,28 +21,72 @@ jobs:
     name: cargo test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions-rust-lang/setup-rust-toolchain@v1
       - run: cargo test --all-features
+
+  # Check formatting with rustfmt
+  formatting:
+    name: cargo fmt
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      # Ensure rustfmt is installed and setup problem matcher
+      - uses: actions-rust-lang/setup-rust-toolchain@v1
+        with:
+          components: rustfmt
+      - name: Rustfmt Check
+        uses: actions-rust-lang/rustfmt@v1
 ```
 
 ## Inputs
 
 All inputs are optional.
+If a [toolchain file](https://rust-lang.github.io/rustup/overrides.html#the-toolchain-file) (i.e., `rust-toolchain` or `rust-toolchain.toml`) is found in the root of the repository and no `toolchain` value is provided, all items specified in the toolchain file will be installed.
+If a `toolchain` value is provided, the toolchain file will be ignored.
+If no `toolchain` value or toolchain file is present, it will default to `stable`.
+First, all items specified in the toolchain file are installed.
+Afterward, the `components` and `target` specified via inputs are installed in addition to the items from the toolchain file.
 
-| Name         | Description                                                                       | Default |
-| ------------ | --------------------------------------------------------------------------------- | ------- |
-| `toolchain`  | Rustup toolchain specifier e.g. `stable`, `nightly`, `1.42.0`.                    | stable  |
-| `target`     | Additional target support to install e.g. `wasm32-unknown-unknown`                |         |
-| `components` | Comma-separated string of additional components to install e.g. `clippy, rustfmt` |         |
+| Name                | Description                                                                                                              | Default       |
+| ------------------- | ------------------------------------------------------------------------------------------------------------------------ | ------------- |
+| `toolchain`         | Comma-separated list of Rustup toolchain specifier e.g. `stable`, `nightly`, `1.42.0`.  The last version is the default. | stable        |
+| `target`            | Additional target support to install e.g. `wasm32-unknown-unknown`                                                       |               |
+| `components`        | Comma-separated string of additional components to install e.g. `clippy, rustfmt`                                        |               |
+| `cache`             | Automatically configure Rust cache (using [`Swatinem/rust-cache`])                                                       | true          |
+| `cache-directories` | Propagates the value to [`Swatinem/rust-cache`]                                                                          |               |
+| `cache-workspaces`  | Propagates the value to [`Swatinem/rust-cache`]                                                                          |               |
+| `cache-on-failure`  | Propagates the value to [`Swatinem/rust-cache`]                                                                          | true          |
+| `cache-key`         | Propagates the value to [`Swatinem/rust-cache`] as `key`                                                                 |               |
+| `matcher`           | Enable problem matcher to surface build messages and formatting issues                                                   | true          |
+| `rustflags`         | Set the value of `RUSTFLAGS` (set to empty string to avoid overwriting existing flags)                                   | "-D warnings" |
+| `override`          | Setup the last installed toolchain as the default via `rustup override`                                                  | true          |
+
+[`Swatinem/rust-cache`]: https://github.com/Swatinem/rust-cache
+
+### RUSTFLAGS
+
+By default, this action sets the `RUSTFLAGS` environment variable to `-D warnings`.
+However, rustflags sources are mutually exclusive, so setting this environment variable omits any configuration through `target.*.rustflags` or `build.rustflags`.
+
+* If `RUSTFLAGS` is already set, no modifications of the variable are made and the original value remains.
+* If `RUSTFLAGS` is unset and the `rustflags` input is empty (i.e., the empty string), then it will remain unset.
+    Use this, if you want to prevent the value from being set because you make use of `target.*.rustflags` or `build.rustflags`.
+* Otherwise, the environment variable `RUSTFLAGS` is set to the content of `rustflags`.
+
+To prevent this from happening, set the `rustflags` input to an empty string, which will
+prevent the action from setting `RUSTFLAGS` at all, keeping any existing preferences.
+
+You can read more rustflags, and their load order, in the [Cargo reference].
 
 ## Outputs
 
-| Name             | Description                               |
-| ---------------- | ----------------------------------------- |
-| `rustc-version`  | Version as reported by `rustc --version`  |
-| `cargo-version`  | Version as reported by `cargo --version`  |
-| `rustup-version` | Version as reported by `rustup --version` |
+| Name             | Description                                 |
+| ---------------- | ------------------------------------------- |
+| `rustc-version`  | Version as reported by `rustc --version`    |
+| `cargo-version`  | Version as reported by `cargo --version`    |
+| `rustup-version` | Version as reported by `rustup --version`   |
+| `cachekey`       | A short hash of the installed rustc version |
 
 ## License
 
@@ -51,3 +95,4 @@ License].
 
 [MIT License]: LICENSE
 [Problem Matchers]: https://github.com/actions/toolkit/blob/main/docs/problem-matchers.md
+[Cargo reference]: https://doc.rust-lang.org/cargo/reference/config.html?highlight=unknown#buildrustflags

action.yml

@@ -13,15 +13,43 @@ branding:
 # The action is heavily inspired by https://github.com/dtolnay/rust-toolchain
 inputs:
   toolchain:
-    description: "Rust toolchain specification -- see https://rust-lang.github.io/rustup/concepts/toolchains.html#toolchain-specification"
+    description: "Comma-separated list of Rust toolchain specifications. Last version becomes the default. -- see https://rust-lang.github.io/rustup/concepts/toolchains.html#toolchain-specification"
     required: false
-    default: "stable"
   target:
     description: "Target triple to install for this toolchain"
     required: false
   components:
     description: "Comma-separated list of components to be additionally installed"
     required: false
+  cache:
+    description: "Automatically configure Rust cache"
+    required: false
+    default: "true"
+  cache-workspaces:
+    description: "Paths to multiple Cargo workspaces and their target directories, separated by newlines."
+    required: false
+  cache-directories:
+    description: "Additional non workspace directories to be cached, separated by newlines."
+    required: false
+  cache-on-failure:
+    description: "Also cache on workflow failures"
+    default: "true"
+    required: false
+  cache-key:
+    description: "An additional cache key that is added alongside the automatic `job`-based cache key and can be used to further differentiate jobs."
+    required: false
+  matcher:
+    description: "Enable the Rust problem matcher"
+    required: false
+    default: "true"
+  rustflags:
+    description: "set RUSTFLAGS environment variable, set to empty string to avoid overwriting build.rustflags"
+    required: false
+    default: "-D warnings"
+  override:
+    description: "Setup the last installed toolchain as the default via `rustup override`"
+    required: false
+    default: "true"
 
 outputs:
   rustc-version:
@@ -33,46 +61,142 @@ outputs:
   rustup-version:
     description: "Version as reported by `rustup --version`"
     value: ${{steps.versions.outputs.rustup-version}}
+  cachekey:
+    description: A short hash of the rustc version, appropriate for use as a cache key. "20220627a831"
+    value: ${{steps.versions.outputs.cachekey}}
 
 runs:
   using: composite
   steps:
-    - id: flags
+    # The later code uses "newer" bash features, which are not available in the ancient bash 3 (from 2014) of macOS
+    - name: Unbork mac
+      if: runner.os == 'macOS'
       run: |
-        : construct rustup command line
-        echo "::set-output name=targets::$(for t in ${targets//,/ }; do echo -n ' --target' $t; done)"
-        echo "::set-output name=components::$(for c in ${components//,/ }; do echo -n ' --component' $c; done)"
-        echo "::set-output name=downgrade::${{inputs.toolchain == 'nightly' && inputs.components && ' --allow-downgrade' || ''}}"
+        brew install bash
+      shell: bash
+
+    - id: flags
       env:
         targets: ${{inputs.target}}
         components: ${{inputs.components}}
       shell: bash
-    - name: rustup toolchain install ${{inputs.toolchain}}
       run: |
-        rustup toolchain install ${{inputs.toolchain}}${{steps.flags.outputs.targets}}${{steps.flags.outputs.components}} --profile minimal${{steps.flags.outputs.downgrade}} --no-self-update
-        rustup default ${{inputs.toolchain}}
-      shell: bash
-    - name: Print installed versions
-      id: versions
-      run: |
-        echo "::set-output name=rustc-version::$(rustc --version)"
-        rustc --version
-        echo "::set-output name=cargo-version::$(cargo --version)"
-        cargo --version
-        echo "::set-output name=rustup-version::$(rustup --version)"
-        rustup --version
-      shell: bash
+        : construct rustup command line
+        echo "targets=$(for t in ${targets//,/ }; do echo -n ' --target' $t; done)" >> $GITHUB_OUTPUT
+        echo "components=$(for c in ${components//,/ }; do echo -n ' --component' $c; done)" >> $GITHUB_OUTPUT
+        echo "downgrade=${{contains(inputs.toolchain, 'nightly') && inputs.components && ' --allow-downgrade' || ''}}" >> $GITHUB_OUTPUT
 
-    - name: "Setup Rust Caching"
-      uses: Swatinem/rust-cache@v1
-    - name: "Install Rust Problem Matcher"
-      run: echo "::add-matcher::${{ github.action_path }}/rust.json"
+    # The environment variables always need to be set before the caching action
+    - name: Setting Environment Variables
+      env:
+        NEW_RUSTFLAGS: ${{inputs.rustflags}}
       shell: bash
-    - name: "Setting Environment Variables"
       run: |
-        echo "CARGO_INCREMENTAL=0" >> $GITHUB_ENV
-        echo "CARGO_PROFILE_DEV_DEBUG=0" >> $GITHUB_ENV
-        echo "CARGO_TERM_COLOR=always" >> $GITHUB_ENV
-        echo "RUST_BACKTRACE=short" >> $GITHUB_ENV
-        echo "RUSTFLAGS=-D warnings" >> $GITHUB_ENV
+        if [[ ! -v CARGO_INCREMENTAL ]]; then
+          echo "CARGO_INCREMENTAL=0" >> $GITHUB_ENV
+        fi
+        if [[ ! -v CARGO_PROFILE_DEV_DEBUG ]]; then
+          echo "CARGO_PROFILE_DEV_DEBUG=0" >> $GITHUB_ENV
+        fi
+        if [[ ! -v CARGO_TERM_COLOR ]]; then
+          echo "CARGO_TERM_COLOR=always" >> $GITHUB_ENV
+        fi
+        if [[ ! -v RUST_BACKTRACE ]]; then
+          echo "RUST_BACKTRACE=short" >> $GITHUB_ENV
+        fi
+        if [[ ( ! -v RUSTFLAGS ) && $NEW_RUSTFLAGS != "" ]]; then
+          echo "RUSTFLAGS=$NEW_RUSTFLAGS" >> $GITHUB_ENV
+        fi
+        # Enable faster sparse index on nightly
+        # The value is ignored on stable and causes no problems
+        # https://internals.rust-lang.org/t/call-for-testing-cargo-sparse-registry/16862
+        if [[ ! -v CARGO_UNSTABLE_SPARSE_REGISTRY ]]; then
+          echo "CARGO_UNSTABLE_SPARSE_REGISTRY=true" >> $GITHUB_ENV
+        fi
+        if [[ ! -v CARGO_REGISTRIES_CRATES_IO_PROTOCOL ]]; then
+          echo "CARGO_REGISTRIES_CRATES_IO_PROTOCOL=sparse" >> $GITHUB_ENV
+        fi
+
+    - name: Install Rust Problem Matcher
+      if: inputs.matcher == 'true'
       shell: bash
+      run: echo "::add-matcher::${{ github.action_path }}/rust.json"
+
+    - name: Install rustup, if needed
+      if: runner.os != 'Windows'
+      shell: bash
+      run: |
+        if ! command -v rustup &> /dev/null ; then
+          curl --proto '=https' --tlsv1.2 --retry 10 --retry-connrefused -fsSL "https://sh.rustup.rs" | sh -s -- --default-toolchain none -y
+          echo "${CARGO_HOME:-$HOME/.cargo}/bin" >> $GITHUB_PATH
+        fi
+
+    - name: rustup toolchain install ${{inputs.toolchain || 'stable'}}
+      env:
+        toolchain: ${{inputs.toolchain}}
+        targets: ${{inputs.target}}
+        components: ${{inputs.components}}
+        override: ${{inputs.override}}
+      shell: bash
+      run: |
+        if [[ -z "$toolchain" && ( -f "rust-toolchain" || -f "rust-toolchain.toml" ) ]]
+        then
+          # Install the toolchain as specified in the file
+          # rustup show is the old way that implicitly installed a toolchain
+          # rustup toolchain install is the new explicit way
+          # https://github.com/rust-lang/rustup/issues/3635#issuecomment-2343511297
+          rustup show active-toolchain || rustup toolchain install
+          if [[ -n $components ]]; then
+            rustup component add ${components//,/ }
+          fi
+          if [[ -n $targets ]]; then
+            rustup target add ${targets//,/ }
+          fi
+        else
+          if [[ -z "$toolchain" ]]
+          then
+            toolchain=stable
+          fi
+          rustup toolchain install ${toolchain//,/ } ${{steps.flags.outputs.targets}}${{steps.flags.outputs.components}} --profile minimal${{steps.flags.outputs.downgrade}} --no-self-update
+          # Take the last element from the list
+          if [[ "$override" == "true" ]]
+          then
+            rustup override set ${toolchain//*,/ }
+          fi
+        fi
+
+    - id: versions
+      name: Print installed versions
+      shell: bash
+      run: |
+        echo "rustc-version=$(rustc --version)" >> $GITHUB_OUTPUT
+        rustc --version --verbose
+        echo "cargo-version=$(cargo --version)" >> $GITHUB_OUTPUT
+        cargo --version --verbose
+        echo "rustup-version=$(rustup --version)" >> $GITHUB_OUTPUT
+        rustup --version
+
+        DATE=$(rustc --version --verbose | sed -ne 's/^commit-date: \(20[0-9][0-9]\)-\([01][0-9]\)-\([0-3][0-9]\)$/\1\2\3/p')
+        HASH=$(rustc --version --verbose | sed -ne 's/^commit-hash: //p')
+        echo "cachekey=$(echo $DATE$HASH | head -c12)" >> $GITHUB_OUTPUT
+
+    - name: Downgrade registry access protocol when needed
+      shell: bash
+      run: |
+        # Not all versions support setting CARGO_REGISTRIES_CRATES_IO_PROTOCOL
+        # On versions 1.66, 1.67, and 1.68.0-nightly the value "sparse" is still unstable.
+        # https://github.com/dtolnay/rust-toolchain/pull/69#discussion_r1107268108
+        # If we detect an incompatible value, set it to "git" which is always supported.
+        if [[ "${{steps.versions.outputs.rustc-version}}" =~ ^rustc\ (1\.6[67]\.|1\.68\.0-nightly) && "${CARGO_REGISTRIES_CRATES_IO_PROTOCOL}" == "sparse" ]]; then
+          echo "Downgrade cargo registry protocol to git"
+          echo "CARGO_REGISTRIES_CRATES_IO_PROTOCOL=git" >> $GITHUB_ENV
+        fi
+
+    - name: Setup Rust Caching
+      if: inputs.cache == 'true'
+      uses: Swatinem/rust-cache@v2
+      with:
+        workspaces: ${{inputs.cache-workspaces}}
+        cache-directories: ${{inputs.cache-directories}}
+        cache-on-failure: ${{inputs.cache-on-failure}}
+        key: ${{inputs.cache-key}}

rust.json

@@ -16,16 +16,16 @@
             "owner": "clippy",
             "pattern": [
                 {
-                    "regexp": "^(warning|warn|error)(\\[(.*)\\])?: (.*)$",
+                    "regexp": "^(?:\\x1b\\[[\\d;]+m)*(warning|warn|error)(?:\\x1b\\[[\\d;]+m)*(\\[(.*)\\])?(?:\\x1b\\[[\\d;]+m)*:(?:\\x1b\\[[\\d;]+m)* ([^\\x1b]*)(?:\\x1b\\[[\\d;]+m)*$",
                     "severity": 1,
                     "message": 4,
                     "code": 3
                 },
                 {
-                    "regexp": "^([\\s->=]*(.*):(\\d*):(\\d*)|.*)$",
-                    "file": 2,
-                    "line": 3,
-                    "column": 4
+                    "regexp": "^(?:\\x1b\\[[\\d;]+m)*\\s*(?:\\x1b\\[[\\d;]+m)*\\s*--> (?:\\x1b\\[[\\d;]+m)*(.*):(\\d*):(\\d*)(?:\\x1b\\[[\\d;]+m)*$",
+                    "file": 1,
+                    "line": 2,
+                    "column": 3
                 }
             ]
         }

test-workspace/Cargo.lock

@@ -0,0 +1,16 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "ci"
+version = "0.1.0"
+dependencies = [
+ "serde_as",
+]
+
+[[package]]
+name = "serde_as"
+version = "0.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4ee4afe4c5c3b69699c4267ae42b838e911466d7ca0005046adc93ac95bb16dd"

test-workspace/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "ci"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+serde_as = "0.0.1"

test-workspace/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}