From 4b930c0a0520e9f837610565442af3afbce79689 Mon Sep 17 00:00:00 2001
From: Taiki Endo <te316e89@gmail.com>
Date: Mon, 8 Sep 2025 00:22:36 +0900
Subject: [PATCH] Add `fallback: cargo-install` input option to use `cargo
 install` for fallback

---
 .github/workflows/ci.yml | 31 +++++++++++++++++++++++++++
 CHANGELOG.md             |  2 ++
 README.md                |  5 +++--
 action.yml               |  2 +-
 main.sh                  | 46 ++++++++++++++++++++++++----------------
 5 files changed, 65 insertions(+), 21 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b120fe42..1c13ccaf 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -162,6 +162,37 @@ jobs:
         run: cargo-nextest nextest --version && taplo --version
         shell: sh
 
+  test-fallback:
+    strategy:
+      fail-fast: false
+      matrix:
+        fallback:
+          - none
+          - cargo-install
+    runs-on: ubuntu-24.04-arm
+    timeout-minutes: 60
+    steps:
+      - uses: taiki-e/checkout-action@v1
+      # cross attempts to install rust-src when Cargo.toml is available even if `cross --version`
+      - run: rm -- Cargo.toml
+      - run: env
+      - uses: ./
+        id: install
+        continue-on-error: ${{ matrix.fallback == 'none' }}
+        with:
+          tool: parse-changelog@0.4.6
+          fallback: ${{ matrix.fallback }}
+      - run: exit 1
+        if: matrix.fallback == 'none' && steps.install.outcome != 'failure'
+      - name: Test bash
+        run: parse-changelog --version
+        shell: bash
+        if: matrix.fallback != 'none'
+      - name: Test sh
+        run: parse-changelog --version
+        shell: sh
+        if: matrix.fallback != 'none'
+
   test-container:
     strategy:
       fail-fast: false
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9957a832..92365cf1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
 
 ## [Unreleased]
 
+- Add `fallback: cargo-install` input option to use `cargo install` instead of `cargo-binstall` for fallback.
+
 - Accept `typos-cli` as an alias for `typos`.
 
 - Accept `wasm-bindgen-cli` as an alias for `wasm-bindgen`.
diff --git a/README.md b/README.md
index 5fc0a18e..36a1788b 100644
--- a/README.md
+++ b/README.md
@@ -86,8 +86,9 @@ If you want to ensure that fallback is not used, use `fallback: none`.
   with:
     tool: cargo-hack
     # Possible values:
-    # - none: disable all fallback
-    # - cargo-binstall (default): cargo-binstall (includes quickinstall)
+    # - none: disable all fallback options
+    # - cargo-binstall (default): use cargo-binstall (includes quickinstall)
+    # - cargo-install: use `cargo install`
     fallback: none
 ```
 
diff --git a/action.yml b/action.yml
index 1961a958..98cadc33 100644
--- a/action.yml
+++ b/action.yml
@@ -11,7 +11,7 @@ inputs:
     required: false
     default: 'true'
   fallback:
-    description: Whether to use fallback (none or cargo-binstall)
+    description: Whether to use fallback (none, cargo-binstall, cargo-install)
     required: false
     default: 'cargo-binstall'
 
diff --git a/main.sh b/main.sh
index 9ceeb68d..abaa6ee3 100755
--- a/main.sh
+++ b/main.sh
@@ -459,8 +459,8 @@ esac
 
 fallback="${INPUT_FALLBACK:-}"
 case "${fallback}" in
-  none | cargo-binstall) ;;
-  *) bail "'fallback' input option must be 'none' or 'cargo-binstall': '${fallback}'" ;;
+  none | cargo-binstall | cargo-install) ;;
+  *) bail "'fallback' input option must be 'none', 'cargo-binstall', or 'cargo-install': '${fallback}'" ;;
 esac
 
 # Refs: https://github.com/rust-lang/rustup/blob/HEAD/rustup-init.sh
@@ -859,20 +859,30 @@ if [[ ${#unsupported_tools[@]} -gt 0 ]]; then
   case "${fallback}" in
     none) bail "install-action does not support ${unsupported_tools[*]} (fallback is disabled by 'fallback: none' input option)" ;;
   esac
-  info "install-action does not support ${unsupported_tools[*]}; fallback to cargo-binstall"
-  IFS=$'\n\t'
-  install_cargo_binstall
-  if [[ -z "${GITHUB_TOKEN:-}" ]] && [[ -n "${DEFAULT_GITHUB_TOKEN:-}" ]]; then
-    export GITHUB_TOKEN="${DEFAULT_GITHUB_TOKEN}"
-  fi
-  # By default, cargo-binstall enforce downloads over secure transports only.
-  # As a result, http will be disabled, and it will also set
-  # min tls version to be 1.2
-  cargo-binstall binstall --force --no-confirm --locked "${unsupported_tools[@]}"
-  if ! type -P cargo >/dev/null; then
-    _bin_dir=$(canonicalize_windows_path "${home}/.cargo/bin")
-    # TODO: avoid this when already added
-    info "adding '${_bin_dir}' to PATH"
-    printf '%s\n' "${_bin_dir}" >>"${GITHUB_PATH}"
-  fi
+  case "${fallback}" in
+    cargo-binstall)
+      info "install-action does not support ${unsupported_tools[*]}; fallback to cargo-binstall"
+      IFS=$'\n\t'
+      install_cargo_binstall
+      if [[ -z "${GITHUB_TOKEN:-}" ]] && [[ -n "${DEFAULT_GITHUB_TOKEN:-}" ]]; then
+        export GITHUB_TOKEN="${DEFAULT_GITHUB_TOKEN}"
+      fi
+      # By default, cargo-binstall enforce downloads over secure transports only.
+      # As a result, http will be disabled, and it will also set
+      # min tls version to be 1.2
+      cargo-binstall binstall --force --no-confirm --locked "${unsupported_tools[@]}"
+      if ! type -P cargo >/dev/null; then
+        _bin_dir=$(canonicalize_windows_path "${home}/.cargo/bin")
+        # TODO: avoid this when already added
+        info "adding '${_bin_dir}' to PATH"
+        printf '%s\n' "${_bin_dir}" >>"${GITHUB_PATH}"
+      fi
+      ;;
+    cargo-install)
+      info "install-action does not support ${unsupported_tools[*]}; fallback to cargo-install"
+      IFS=$'\n\t'
+      cargo install --locked "${unsupported_tools[@]}"
+      ;;
+    *) bail "unhandled fallback ${fallback}" ;;
+  esac
 fi