Add inputs to control the Rust toolchain (#34)

* Add inputs for controlling rust toolchain

* Add tests for new inputs

* Negated ifs!

* Fix action input name

* Better description of rust-override

* New logic of choosing toolchain

* Add explaining comment.

* Add rust-toolchain.toml test

.github/workflows/test-inputs.yml

@@ -186,3 +186,157 @@ jobs:
         run: |
           echo "Error! The action should have failed because of the breaking change, but it has not."
           exit 1
+
+  test-rust-toolchain-against-directory-override:
+    name: Test the action against toolchain override set using rustup
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout the test repository
+        uses: actions/checkout@v3
+        with:
+          repository: mgr0dzicki/cargo-semver-action-ref-slice
+          ref: patch_change
+      - name: Checkout the action
+        uses: actions/checkout@v3
+        with:
+          path: action
+      - name: Install latest beta
+        uses: dtolnay/rust-toolchain@beta
+      - name: Set local override to beta
+        run: rustup override set beta
+      - name: Run the action with rust-toolchain set to nightly
+        uses: ./action/
+        with:
+          rust-toolchain: nightly
+      - name: Get cache key
+        uses: actions/cache/restore@v3
+        id: get-cache-key
+        with:
+          path: ${{ github.workspace }}/semver-checks/target/semver-checks/cache
+          fail-on-cache-miss: true
+          lookup-only: true
+          key: -${{ github.job }}
+          restore-keys: |
+            -${{ github.job }}
+      - name: Fail if the toolchain used by the action is invalid
+        if: ${{ ! contains(steps.get-cache-key.outputs.cache-matched-key, 'nightly') }}
+        run: |
+          echo "The toolchain used by the action should be nightly, but it is not!"
+          exit 1
+      - name: Check the active toolchain
+        run: |
+          if ! rustup show active-toolchain | grep -q "beta"; then
+            echo "The active toolchain should be still beta, but it is $(rustup show active-toolchain)!"
+            exit 1
+          fi
+
+  test-rust-toolchain-against-toml-override:
+    name: Test the action against toolchain override specified in rust-toolchain.toml file
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout the test repository
+        uses: actions/checkout@v3
+        with:
+          repository: mgr0dzicki/cargo-semver-action-ref-slice
+          ref: patch_change
+      - name: Checkout the action
+        uses: actions/checkout@v3
+        with:
+          path: action
+      - name: Install latest beta
+        uses: dtolnay/rust-toolchain@beta
+      - name: Set override to beta in rust-toolchain.toml file
+        run: echo -e "[toolchain]\nchannel = \"beta\"" > rust-toolchain.toml
+      - name: Run the action with rust-toolchain set to nightly
+        uses: ./action/
+        with:
+          rust-toolchain: nightly
+      - name: Get cache key
+        uses: actions/cache/restore@v3
+        id: get-cache-key
+        with:
+          path: ${{ github.workspace }}/semver-checks/target/semver-checks/cache
+          fail-on-cache-miss: true
+          lookup-only: true
+          key: -${{ github.job }}
+          restore-keys: |
+            -${{ github.job }}
+      - name: Fail if the toolchain used by the action is invalid
+        if: ${{ ! contains(steps.get-cache-key.outputs.cache-matched-key, 'nightly') }}
+        run: |
+          echo "The toolchain used by the action should be nightly, but it is not!"
+          exit 1
+      - name: Check the active toolchain
+        run: |
+          if ! rustup show active-toolchain | grep -q "beta"; then
+            echo "The active toolchain should be still beta, but it is $(rustup show active-toolchain)!"
+            exit 1
+          fi
+
+  test-rust-toolchain-empty:
+    name: Test whether action works properly with rust-toolchain set to an empty string
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout the test repository
+        uses: actions/checkout@v3
+        with:
+          repository: mgr0dzicki/cargo-semver-action-ref-slice
+          ref: patch_change
+      - name: Checkout the action
+        uses: actions/checkout@v3
+        with:
+          path: action
+      - name: Install latest beta
+        uses: dtolnay/rust-toolchain@beta
+      - name: Set local override to beta
+        run: rustup override set beta
+      - name: Run the action with empty rust-toolchain
+        uses: ./action/
+        with:
+          rust-toolchain: ''
+      - name: Get cache key
+        uses: actions/cache/restore@v3
+        id: get-cache-key
+        with:
+          path: ${{ github.workspace }}/semver-checks/target/semver-checks/cache
+          fail-on-cache-miss: true
+          lookup-only: true
+          key: -${{ github.job }}
+          restore-keys: |
+            -${{ github.job }}
+      - name: Fail if the toolchain used by the action is invalid
+        if: ${{ ! contains(steps.get-cache-key.outputs.cache-matched-key, 'beta') }}
+        run: |
+          echo "The toolchain used by the action should be beta, but it is not!"
+          exit 1
+      - name: Uninstall Rust
+        run: rustup self uninstall -y
+      - name: Run the action with empty rust-toolchain (allowed to fail)
+        id: action_without_rust
+        uses: ./action/
+        with:
+          rust-toolchain: ''
+        continue-on-error: true
+      - name: Fail if the action has not returned any errors (but it should have)
+        if: steps.action_without_rust.outcome != 'failure'
+        run: |
+          echo "Error! The action should have failed because the Rust is not installed and rust-toolchain was set to '', but it has not."
+          exit 1
+
+  test-rust-toolchain-installs-rust:
+    name: Test whether action installs Rust toolchain by default
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout the test repository
+        uses: actions/checkout@v3
+        with:
+          repository: mgr0dzicki/cargo-semver-action-ref-slice
+          ref: patch_change
+      - name: Checkout the action
+        uses: actions/checkout@v3
+        with:
+          path: action
+      - name: Uninstall Rust
+        run: rustup self uninstall -y
+      - name: Run the action with default arguments
+        uses: ./action/

README.md

@@ -19,6 +19,7 @@ Every argument is optional.
 | `package`            | The package whose API to check for semver (in Package Id Specification format, see https://doc.rust-lang.org/cargo/reference/pkgid-spec.html for reference). If not set, all packages defined in the Cargo.toml file are processed. | |
 | `manifest-path`      | Path to Cargo.toml of crate or workspace to check. If not specified, the action assumes the manifest is under the default [`GITHUB_WORKSPACE`](https://docs.github.com/en/actions/learn-github-actions/variables#default-environment-variables) path. | |
 | `verbose`            | Enables verbose output of `cargo-semver-checks`. | `false` |
+| `rust-toolchain`     | Rust toolchain name to use, e.g. `stable`, `nightly` or `1.68.0`. It will be installed if necessary and used regardless of local overrides and the `rust-toolchain.toml` file. However, if the input is set to be an empty string, the action assumes some Rust toolchain is already installed and uses the default one. | `stable` |
 | `cache-key`          | Rustdoc baseline is cached separately for runs that differ in at least one of the following: runner OS, `rustc` version, `cargo-semver-checks` version, or any of the `Cargo.lock` files in the current workspace. This input might be used to further separate the caches by providing the unique key (by default the job name) for each of them. | `${{ github.job }}` |
 | `prefix-key`         | Additional prefix of the cache key, can be set to start a new cache manually. | |
 | `github-token`       | The `GITHUB_TOKEN` secret used to download precompiled binaries from GitHub API. If not specified, the [automatic GitHub token](https://docs.github.com/en/actions/security-guides/automatic-token-authentication) provided to the workflow will be used. The token may be alternatively passed in an environment variable `GITHUB_TOKEN`. | `${{ github.token }}` |

action.yml

@@ -15,6 +15,10 @@ inputs:
     type: boolean
     required: true
     default: false
+  rust-toolchain:
+    description: 'Rust toolchain name to use, e.g. `stable`, `nightly` or `1.68.0`. It will be installed if necessary and used regardless of local overrides and the `rust-toolchain.toml` file. However, if the input is set to be an empty string, the action assumes some Rust toolchain is already installed and uses the default one.'
+    required: false
+    default: 'stable'
   cache-key:
     description: 'Rustdoc baseline is cached separately for runs that differ in at least one of the following: runner OS, `rustc` version, `cargo-semver-checks` version, or any of the `Cargo.lock` files in the current workspace. This input might be used to further separate the caches by providing the unique key (by default the job name) for each of them.'
     required: false

src/main.ts

@@ -72,11 +72,18 @@ async function getCargoSemverChecksDownloadURL(target: string): Promise<string>
     return asset.url;
 }
 
-async function installRustUp(): Promise<void> {
+async function installRustUpIfRequested(): Promise<void> {
-    const rustup = await rustCore.RustUp.getOrInstall();
+    const toolchain = rustCore.input.getInput("rust-toolchain");
-    await rustup.call(["show"]);
+    if (toolchain) {
-    await rustup.setProfile("minimal");
+        const rustup = await rustCore.RustUp.getOrInstall();
-    await rustup.installToolchain("stable");
+        await rustup.call(["show"]);
+        await rustup.setProfile("minimal");
+        await rustup.installToolchain(toolchain);
+
+        // Setting the environment variable here affects only processes spawned
+        // by this action, so it will not override the default toolchain globally.
+        process.env["RUSTUP_TOOLCHAIN"] = toolchain;
+    }
 }
 
 async function runCargoSemverChecks(cargo: rustCore.Cargo): Promise<void> {
@@ -127,7 +134,7 @@ async function run(): Promise<void> {
     const manifestPath = path.resolve(rustCore.input.getInput("manifest-path") || "./");
     const manifestDir = path.extname(manifestPath) ? path.dirname(manifestPath) : manifestPath;
 
-    await installRustUp();
+    await installRustUpIfRequested();
 
     const cargo = await rustCore.Cargo.get();