Merge 14150cf66c into 12cd2235ef

* trim only ascii whitespace for branch

* rebuild

.github/copilot-instructions.md

@@ -0,0 +1,121 @@
+# GitHub Actions Checkout - AI Coding Instructions
+
+## Project Overview
+
+This is the official `actions/checkout` GitHub Action for checking out repositories in workflows. It's a TypeScript project that compiles to a single bundled JavaScript file (`dist/index.js`) and supports both git-based and REST API-based repository downloads.
+
+## Architecture & Key Components
+
+### Core Entry Points
+- **`src/main.ts`**: Main entry point with `run()` and `cleanup()` functions, determined by `stateHelper.IsPost`
+- **`src/git-source-provider.ts`**: Primary orchestrator for repository acquisition (git vs REST API fallback)
+- **`src/input-helper.ts`**: Input validation and GitHub Actions input processing
+- **`action.yml`**: Defines the action interface with comprehensive input/output schema
+
+### Critical Data Flow
+1. `main.ts` → `inputHelper.getInputs()` → validates and transforms action inputs
+2. `main.ts` → `gitSourceProvider.getSource(settings)` → orchestrates repository download
+3. `git-source-provider.ts` decides: use Git CLI or fallback to GitHub REST API
+4. State management via `state-helper.ts` for POST action cleanup
+
+### Authentication & Security Patterns
+- **Token-based auth**: Uses `@actions/core` to handle GitHub tokens securely
+- **SSH key management**: Configures temporary SSH keys in `git-auth-helper.ts`
+- **Safe directory**: Automatically configures `git config safe.directory` for container compatibility
+
+## Development Workflow
+
+### Essential Commands
+```bash
+npm ci                    # Install dependencies
+npm run build            # TypeScript → JavaScript + bundle with ncc + generate docs
+npm run format           # Prettier formatting
+npm run lint            # ESLint validation
+npm test                # Jest test suite
+```
+
+### Build Process (Critical!)
+- **`npm run build`** runs: `tsc && ncc build && node lib/misc/generate-docs.js`
+- **Documentation sync**: `src/misc/generate-docs.ts` auto-updates README.md usage section from `action.yml`
+- **Bundling**: Uses `@vercel/ncc` to create single `dist/index.js` file
+- **Always run `npm run build` before commits** - the `dist/` directory must be up-to-date
+
+### Testing Strategy
+- **Unit tests**: Jest tests in `__test__/` for all core modules
+- **Integration tests**: Shell scripts (`__test__/verify-*.sh`) test real git operations
+- **E2E tests**: `.github/workflows/test.yml` tests across OS matrix with actual GitHub repos
+
+## Project-Specific Conventions
+
+### TypeScript Patterns
+- **Interface-driven**: `IGitSourceSettings` centralizes all configuration
+- **Async/await**: All I/O operations use async patterns, not promises
+- **Error handling**: Use `core.setFailed()` for action failures, `core.warning()` for non-critical issues
+
+### Git Operation Patterns
+```typescript
+// Check Git version and fallback pattern
+const git = await getGitCommandManager(settings)
+if (git) {
+  // Use Git CLI
+  await git.fetch(refSpec, fetchDepth)
+} else {
+  // Fallback to REST API
+  await githubApiHelper.downloadRepository(...)
+}
+```
+
+### State Management (Unique Pattern!)
+- **Dual-phase execution**: Same script runs twice (MAIN + POST) determined by `stateHelper.IsPost`
+- **State persistence**: Use `core.saveState()` / `core.getState()` to pass data between phases
+- **Cleanup responsibility**: POST phase cleans up auth tokens, SSH keys, etc.
+
+### Input Validation Approach
+- **GitHub context integration**: Defaults repository from `github.context.repo`
+- **Path safety**: Validates paths are within `GITHUB_WORKSPACE`
+- **Flexible refs**: Handles branches, tags, SHAs, and PR refs uniformly
+
+## Integration Points
+
+### GitHub Actions SDK Usage
+- **`@actions/core`**: Input/output, logging, state management
+- **`@actions/github`**: GitHub context and API access
+- **`@actions/exec`**: Git command execution
+- **`@actions/io`**: File system operations
+
+### Git Integration
+- **Version compatibility**: Minimum Git 2.18, with feature detection for sparse-checkout
+- **Authentication modes**: Token-based (default) or SSH key-based
+- **Advanced features**: LFS, submodules, sparse-checkout, partial clones
+
+### Container Support
+- **Safe directory**: Critical for container workflows - auto-configures git safe.directory
+- **Credential persistence**: Configures git credential helper for authenticated operations
+
+## Common Debugging Patterns
+
+### Enable Debug Logging
+```yaml
+steps:
+  - uses: actions/checkout@v5
+    env:
+      ACTIONS_STEP_DEBUG: true
+```
+
+### REST API Fallback Testing
+```bash
+# Force REST API mode by overriding Git version
+__test__/override-git-version.sh
+```
+
+### Authentication Issues
+- Check `GITHUB_TOKEN` permissions: needs `contents: read`
+- For private repos: requires PAT with repo access
+- Container issues: verify safe.directory configuration
+
+## Key Files for Understanding
+- `src/git-source-provider.ts` - Main orchestration logic
+- `src/input-helper.ts` - Action interface and validation
+- `src/git-auth-helper.ts` - Authentication and credential management
+- `action.yml` - Complete input/output specification
+- `.github/workflows/test.yml` - Comprehensive test scenarios

.github/workflows/deno.yml

@@ -0,0 +1,41 @@
+# This workflow uses actions that are not certified by GitHub.
+# They are provided by a third-party and are governed by
+# separate terms of service, privacy policy, and support
+# documentation.
+
+# This workflow will install Deno then run `deno lint` and `deno test`.
+# For more information see: https://github.com/denoland/setup-deno
+
+name: Deno
+
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+    branches: ["main"]
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Setup repo
+        uses: actions/checkout@v4
+
+      - name: Setup Deno
+        uses: denoland/setup-deno@v1.1.2
+        with:
+          deno-version: v1.x
+
+      # Uncomment this step to verify the use of 'deno fmt' on each commit.
+      # - name: Verify formatting
+      #   run: deno fmt --check
+
+      - name: Run linter
+        run: deno lint
+
+      - name: Run tests
+        run: deno test -A

LICENSE

@@ -1,22 +1,201 @@
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__test__/input-helper.test.ts

@@ -24,9 +24,20 @@ const mockGithubContext: any = {
   payload: {}
 }
 
+// Replicate @actions/core getInput behavior: it trims whitespace by default
+// (String.prototype.trim(), which strips characters such as a leading U+FEFF BOM)
+// unless trimWhitespace is explicitly set to false.
+const getInputImpl = (name: string, options?: {trimWhitespace?: boolean}) => {
+  const val = inputs[name] ?? ''
+  if (options && options.trimWhitespace === false) {
+    return val
+  }
+  return typeof val === 'string' ? val.trim() : val
+}
+
 // Mock @actions/core before loading input-helper
 jest.unstable_mockModule('@actions/core', () => ({
-  getInput: jest.fn((name: string) => inputs[name]),
+  getInput: jest.fn(getInputImpl),
   getBooleanInput: jest.fn((name: string) => inputs[name]),
   getMultilineInput: jest.fn((name: string) =>
     inputs[name] ? String(inputs[name]).split('\n').filter(Boolean) : []
@@ -76,9 +87,7 @@ describe('input-helper tests', () => {
     inputs = {}
     jest.clearAllMocks()
     // Re-apply default mocks
-    ;(core.getInput as jest.Mock<any>).mockImplementation(
-      (name: string) => inputs[name]
-    )
+    ;(core.getInput as jest.Mock<any>).mockImplementation(getInputImpl as any)
     mockDirectoryExistsSync.mockImplementation(
       (p: string) => p === gitHubWorkspace
     )
@@ -176,8 +185,84 @@ describe('input-helper tests', () => {
     expect(settings.commit).toBeFalsy()
   })
 
+  it('does not reclassify a ref as sha when a BOM is prefixed', async () => {
+    // A fork branch named "<U+FEFF>" + 40 hex chars. core.getInput trims the
+    // BOM by default, which previously collapsed this into a bare SHA and
+    // bypassed the unsafe fork PR checkout guard.
+    inputs.ref = '\uFEFF522d932fae5296da51fdf431934425ecf891c6a2'
+    const settings: IGitSourceSettings = await inputHelper.getInputs()
+    expect(settings.commit).toBeFalsy()
+    expect(settings.ref).toBe('522d932fae5296da51fdf431934425ecf891c6a2')
+  })
+
+  it('does not reclassify a sha-256 ref as sha when a BOM is prefixed', async () => {
+    inputs.ref =
+      '\uFEFF1111111111222222222233333333334444444444555555555566666666667777'
+    const settings: IGitSourceSettings = await inputHelper.getInputs()
+    expect(settings.commit).toBeFalsy()
+    expect(settings.ref).toBe(
+      '1111111111222222222233333333334444444444555555555566666666667777'
+    )
+  })
+
+  it('treats a sha surrounded by ascii whitespace as a commit', async () => {
+    // ASCII whitespace can only come from the workflow author's YAML (git ref
+    // names cannot contain it), so trimming it and treating the value as a
+    // commit is safe.
+    inputs.ref = '  1111111111222222222233333333334444444444  '
+    const settings: IGitSourceSettings = await inputHelper.getInputs()
+    expect(settings.ref).toBeFalsy()
+    expect(settings.commit).toBe('1111111111222222222233333333334444444444')
+  })
+
   it('sets workflow organization ID', async () => {
     const settings: IGitSourceSettings = await inputHelper.getInputs()
     expect(settings.workflowOrganizationId).toBe(123456)
   })
+
+  describe('unsafe PR checkout guard', () => {
+    const forkPayload = {
+      repository: {id: 100},
+      pull_request: {
+        head: {
+          sha: '1234567890123456789012345678901234567890',
+          repo: {id: 200, full_name: 'attacker/fork'}
+        },
+        merge_commit_sha: 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'
+      }
+    }
+
+    it('allows the default self-checkout on a fork pull_request_target', async () => {
+      const originalEvent = mockGithubContext.eventName
+      const originalPayload = mockGithubContext.payload
+      try {
+        mockGithubContext.eventName = 'pull_request_target'
+        mockGithubContext.payload = forkPayload
+        // Simulate a rebase/fast-forward merge where the base tip (event SHA)
+        // equals the PR head SHA. The default self-checkout must still succeed.
+        mockGithubContext.sha = '1234567890123456789012345678901234567890'
+        const settings: IGitSourceSettings = await inputHelper.getInputs()
+        expect(settings.commit).toBe('1234567890123456789012345678901234567890')
+      } finally {
+        mockGithubContext.eventName = originalEvent
+        mockGithubContext.payload = originalPayload
+      }
+    })
+
+    it('refuses an explicit fork repository on pull_request_target', async () => {
+      const originalEvent = mockGithubContext.eventName
+      const originalPayload = mockGithubContext.payload
+      try {
+        mockGithubContext.eventName = 'pull_request_target'
+        mockGithubContext.payload = forkPayload
+        inputs.repository = 'attacker/fork'
+        await expect(inputHelper.getInputs()).rejects.toThrow(
+          /Refusing to check out fork pull request code/
+        )
+      } finally {
+        mockGithubContext.eventName = originalEvent
+        mockGithubContext.payload = originalPayload
+      }
+    })
+  })
 })

dist/index.js

@@ -42100,6 +42100,22 @@ async function getInputs() {
         `${github_context.repo.owner}/${github_context.repo.repo}`.toUpperCase();
     // Source branch, source version
     result.ref = getInput('ref');
+    // core.getInput()'s default trim strips a range of Unicode characters such as a
+    // leading BOM (U+FEFF) or NBSP (U+00A0). Those are valid in a git ref name, so
+    // a fork branch named "<BOM>" + 40 hex chars would trim down to a bare SHA and
+    // be silently reclassified as a commit, bypassing the unsafe fork PR checkout
+    // guard.
+    //
+    // The trim below strips only the ASCII whitespace characters which are all forbidden
+    // in a git branch name.
+    //   \t  U+0009  horizontal tab   - ASCII control, forbidden in ref names
+    //   \n  U+000A  line feed        - ASCII control, forbidden in ref names
+    //   \v  U+000B  vertical tab     - ASCII control, forbidden in ref names
+    //   \f  U+000C  form feed        - ASCII control, forbidden in ref names
+    //   \r  U+000D  carriage return  - ASCII control, forbidden in ref names
+    //   ' ' U+0020  space            - forbidden in ref names
+    const asciiTrimmedRef = getInput('ref', { trimWhitespace: false })
+        .replace(/^[\t\n\v\f\r ]+|[\t\n\v\f\r ]+$/g, '');
     if (!result.ref) {
         if (isWorkflowRepository) {
             result.ref = github_context.ref;
@@ -42112,8 +42128,8 @@ async function getInputs() {
         }
     }
     // SHA?
-    else if (result.ref.match(/^(?:[0-9a-fA-F]{40}|[0-9a-fA-F]{64})$/)) {
-        result.commit = result.ref;
+    else if (asciiTrimmedRef.match(/^(?:[0-9a-fA-F]{40}|[0-9a-fA-F]{64})$/)) {
+        result.commit = asciiTrimmedRef;
         result.ref = '';
     }
     core_debug(`ref = '${result.ref}'`);
@@ -42191,12 +42207,19 @@ async function getInputs() {
         (getInput('allow-unsafe-pr-checkout') || 'false').toUpperCase() ===
             'TRUE';
     core_debug(`allow unsafe PR checkout = ${result.allowUnsafePrCheckout}`);
-    assertSafePrCheckout({
-        qualifiedRepository,
-        ref: result.ref,
-        commit: result.commit,
-        allowUnsafePrCheckout: result.allowUnsafePrCheckout
-    });
+    // The default self-checkout (this repository with no explicit ref) always
+    // resolves to the trusted ref/commit GitHub set for the triggering event, so
+    // the fork-checkout guard only needs to run when the caller customized the
+    // repository or ref.
+    const isDefaultCheckout = isWorkflowRepository && !getInput('ref');
+    if (!isDefaultCheckout) {
+        assertSafePrCheckout({
+            qualifiedRepository,
+            ref: result.ref,
+            commit: result.commit,
+            allowUnsafePrCheckout: result.allowUnsafePrCheckout
+        });
+    }
     return result;
 }
 

src/input-helper.ts

@@ -59,6 +59,23 @@ export async function getInputs(): Promise<IGitSourceSettings> {
 
   // Source branch, source version
   result.ref = core.getInput('ref')
+  // core.getInput()'s default trim strips a range of Unicode characters such as a
+  // leading BOM (U+FEFF) or NBSP (U+00A0). Those are valid in a git ref name, so
+  // a fork branch named "<BOM>" + 40 hex chars would trim down to a bare SHA and
+  // be silently reclassified as a commit, bypassing the unsafe fork PR checkout
+  // guard.
+  //
+  // The trim below strips only the ASCII whitespace characters which are all forbidden
+  // in a git branch name.
+  //   \t  U+0009  horizontal tab   - ASCII control, forbidden in ref names
+  //   \n  U+000A  line feed        - ASCII control, forbidden in ref names
+  //   \v  U+000B  vertical tab     - ASCII control, forbidden in ref names
+  //   \f  U+000C  form feed        - ASCII control, forbidden in ref names
+  //   \r  U+000D  carriage return  - ASCII control, forbidden in ref names
+  //   ' ' U+0020  space            - forbidden in ref names
+  const asciiTrimmedRef = core
+    .getInput('ref', {trimWhitespace: false})
+    .replace(/^[\t\n\v\f\r ]+|[\t\n\v\f\r ]+$/g, '')
   if (!result.ref) {
     if (isWorkflowRepository) {
       result.ref = github.context.ref
@@ -72,8 +89,8 @@ export async function getInputs(): Promise<IGitSourceSettings> {
     }
   }
   // SHA?
-  else if (result.ref.match(/^(?:[0-9a-fA-F]{40}|[0-9a-fA-F]{64})$/)) {
-    result.commit = result.ref
+  else if (asciiTrimmedRef.match(/^(?:[0-9a-fA-F]{40}|[0-9a-fA-F]{64})$/)) {
+    result.commit = asciiTrimmedRef
     result.ref = ''
   }
   core.debug(`ref = '${result.ref}'`)
@@ -168,12 +185,19 @@ export async function getInputs(): Promise<IGitSourceSettings> {
     'TRUE'
   core.debug(`allow unsafe PR checkout = ${result.allowUnsafePrCheckout}`)
 
-  unsafePrCheckoutHelper.assertSafePrCheckout({
-    qualifiedRepository,
-    ref: result.ref,
-    commit: result.commit,
-    allowUnsafePrCheckout: result.allowUnsafePrCheckout
-  })
+  // The default self-checkout (this repository with no explicit ref) always
+  // resolves to the trusted ref/commit GitHub set for the triggering event, so
+  // the fork-checkout guard only needs to run when the caller customized the
+  // repository or ref.
+  const isDefaultCheckout = isWorkflowRepository && !core.getInput('ref')
+  if (!isDefaultCheckout) {
+    unsafePrCheckoutHelper.assertSafePrCheckout({
+      qualifiedRepository,
+      ref: result.ref,
+      commit: result.commit,
+      allowUnsafePrCheckout: result.allowUnsafePrCheckout
+    })
+  }
 
   return result
 }