Add support for SHA256 repositories

New input parameter 'repo-sha256' to set the Git object format
to "sha256" when initializing a Git repository.

.github/workflows/check-dist.yml

@@ -22,7 +22,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4.1.6
+      - uses: actions/checkout@v6
 
       - name: Set Node.js 24.x
         uses: actions/setup-node@v4

.github/workflows/codeql-analysis.yml

@@ -39,7 +39,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v4.1.6
+      uses: actions/checkout@v6
 
     - name: Initialize CodeQL
       uses: github/codeql-action/init@v3

.github/workflows/licensed.yml

@@ -9,6 +9,6 @@ jobs:
     runs-on: ubuntu-latest
     name: Check licenses
     steps:
-      - uses: actions/checkout@v4.1.6
+      - uses: actions/checkout@v6
       - run: npm ci
       - run: npm run licensed-check

.github/workflows/publish-immutable-actions.yml

@@ -14,7 +14,7 @@ jobs:
 
     steps:
       - name: Checking out
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
       - name: Publish
         id: publish
         uses: actions/publish-immutable-action@0.0.3

.github/workflows/test.yml

@@ -19,7 +19,7 @@ jobs:
       - uses: actions/setup-node@v4
         with:
           node-version: 24.x
-      - uses: actions/checkout@v4.1.6
+      - uses: actions/checkout@v6
       - run: npm ci
       - run: npm run build
       - run: npm run format-check
@@ -37,7 +37,7 @@ jobs:
     steps:
       # Clone this repo
       - name: Checkout
-        uses: actions/checkout@v4.1.6
+        uses: actions/checkout@v6
 
       # Basic checkout
       - name: Checkout basic
@@ -87,6 +87,17 @@ jobs:
       - name: Verify fetch filter
         run: __test__/verify-fetch-filter.sh
 
+      # Fetch tags
+      - name: Checkout with fetch-tags
+        uses: ./
+        with:
+          ref: test-data/v2/basic
+          path: fetch-tags-test
+          fetch-tags: true
+      - name: Verify fetch-tags
+        shell: bash
+        run: __test__/verify-fetch-tags.sh
+
       # Sparse checkout
       - name: Sparse checkout
         uses: ./
@@ -165,6 +176,22 @@ jobs:
       - name: Verify submodules recursive
         run: __test__/verify-submodules-recursive.sh
 
+      # Worktree credentials
+      - name: Checkout for worktree test
+        uses: ./
+        with:
+          path: worktree-test
+      - name: Verify worktree credentials
+        shell: bash
+        run: __test__/verify-worktree.sh worktree-test worktree-branch
+
+      # Worktree credentials in container step
+      - name: Verify worktree credentials in container step
+        if: runner.os == 'Linux'
+        uses: docker://bitnami/git:latest
+        with:
+          args: bash __test__/verify-worktree.sh worktree-test container-worktree-branch
+
       # Basic checkout using REST API
       - name: Remove basic
         if: runner.os != 'windows'
@@ -202,7 +229,7 @@ jobs:
     steps:
       # Clone this repo
       - name: Checkout
-        uses: actions/checkout@v4.1.6
+        uses: actions/checkout@v6
 
       # Basic checkout using git
       - name: Checkout basic
@@ -234,7 +261,7 @@ jobs:
     steps:
       # Clone this repo
       - name: Checkout
-        uses: actions/checkout@v4.1.6
+        uses: actions/checkout@v6
 
       # Basic checkout using git
       - name: Checkout basic
@@ -264,7 +291,7 @@ jobs:
     steps:
       # Clone this repo
       - name: Checkout
-        uses: actions/checkout@v4.1.6
+        uses: actions/checkout@v6
         with:
           path: localClone
 
@@ -291,8 +318,8 @@ jobs:
           git fetch --no-tags --depth=1 origin +refs/heads/main:refs/remotes/origin/main
 
       # needed to make checkout post cleanup succeed
-      - name: Fix Checkout v4
-        uses: actions/checkout@v4.1.6
+      - name: Fix Checkout v6
+        uses: actions/checkout@v6
         with:
           path: localClone
 
@@ -301,7 +328,7 @@ jobs:
     steps:
       # Clone this repo
       - name: Checkout
-        uses: actions/checkout@v4.1.6
+        uses: actions/checkout@v6
         with:
           path: actions-checkout
 

.github/workflows/update-main-version.yml

@@ -23,7 +23,7 @@ jobs:
     # Note this update workflow can also be used as a rollback tool.
     # For that reason, it's best to pin `actions/checkout` to a known, stable version
     # (typically, about two releases back).
-    - uses: actions/checkout@v4.1.6
+    - uses: actions/checkout@v6
       with:
         fetch-depth: 0
     - name: Git config

.github/workflows/update-test-ubuntu-git.yml

@@ -26,7 +26,7 @@ jobs:
  
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # Use `docker/login-action` to log in to GHCR.io. 
       # Once published, the packages are scoped to the account defined here.

CHANGELOG.md

@@ -1,19 +1,25 @@
 # Changelog
 
-## V6.0.0
+## v6.0.2
+* Fix tag handling: preserve annotations and explicit fetch-tags by @ericsciple in https://github.com/actions/checkout/pull/2356
+
+## v6.0.1
+* Add worktree support for persist-credentials includeIf by @ericsciple in https://github.com/actions/checkout/pull/2327
+
+## v6.0.0
 * Persist creds to a separate file by @ericsciple in https://github.com/actions/checkout/pull/2286
 * Update README to include Node.js 24 support details and requirements by @salmanmkc in https://github.com/actions/checkout/pull/2248
 
-## V5.0.1
+## v5.0.1
 * Port v6 cleanup to v5 by @ericsciple in https://github.com/actions/checkout/pull/2301
 
-## V5.0.0
+## v5.0.0
 * Update actions checkout to use node 24 by @salmanmkc in https://github.com/actions/checkout/pull/2226
 
-## V4.3.1
+## v4.3.1
 * Port v6 cleanup to v4 by @ericsciple in https://github.com/actions/checkout/pull/2305
 
-## V4.3.0
+## v4.3.0
 * docs: update README.md by @motss in https://github.com/actions/checkout/pull/1971
 * Add internal repos for checking out multiple repositories by @mouismail in https://github.com/actions/checkout/pull/1977
 * Documentation update - add recommended permissions to Readme by @benwells in https://github.com/actions/checkout/pull/2043

README.md

@@ -4,8 +4,9 @@
 
 ## What's new
 
-- Updated `persist-credentials` to store the credentials under `$RUNNER_TEMP` instead of directly in the local git config.
-  - This requires a minimum Actions Runner version of [v2.329.0](https://github.com/actions/runner/releases/tag/v2.329.0) to access the persisted credentials for [Docker container action](https://docs.github.com/en/actions/tutorials/use-containerized-services/create-a-docker-container-action) scenarios.
+- Improved credential security: `persist-credentials` now stores credentials in a separate file under `$RUNNER_TEMP` instead of directly in `.git/config`
+- No workflow changes required — `git fetch`, `git push`, etc. continue to work automatically
+- Running authenticated git commands from a [Docker container action](https://docs.github.com/actions/sharing-automations/creating-actions/creating-a-docker-container-action) requires Actions Runner [v2.329.0](https://github.com/actions/runner/releases/tag/v2.329.0) or later
 
 # Checkout v5
 
@@ -51,7 +52,7 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
 
 <!-- start usage -->
 ```yaml
-- uses: actions/checkout@v5
+- uses: actions/checkout@v6
   with:
     # Repository name with owner. For example, actions/checkout
     # Default: ${{ github.repository }}
@@ -159,6 +160,10 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
     # running from unless specified. Example URLs are https://github.com or
     # https://my-ghes-server.example.com
     github-server-url: ''
+
+    # Set Git object format to "sha256" when initializing a Git repository.
+    # Default: false
+    repo-sha256: ''
 ```
 <!-- end usage -->
 
@@ -190,7 +195,7 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
 ## Fetch only the root files
 
 ```yaml
-- uses: actions/checkout@v5
+- uses: actions/checkout@v6
   with:
     sparse-checkout: .
 ```
@@ -198,7 +203,7 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
 ## Fetch only the root files and `.github` and `src` folder
 
 ```yaml
-- uses: actions/checkout@v5
+- uses: actions/checkout@v6
   with:
     sparse-checkout: |
       .github
@@ -208,7 +213,7 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
 ## Fetch only a single file
 
 ```yaml
-- uses: actions/checkout@v5
+- uses: actions/checkout@v6
   with:
     sparse-checkout: |
       README.md
@@ -218,7 +223,7 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
 ## Fetch all history for all tags and branches
 
 ```yaml
-- uses: actions/checkout@v5
+- uses: actions/checkout@v6
   with:
     fetch-depth: 0
 ```
@@ -226,7 +231,7 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
 ## Checkout a different branch
 
 ```yaml
-- uses: actions/checkout@v5
+- uses: actions/checkout@v6
   with:
     ref: my-branch
 ```
@@ -234,7 +239,7 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
 ## Checkout HEAD^
 
 ```yaml
-- uses: actions/checkout@v5
+- uses: actions/checkout@v6
   with:
     fetch-depth: 2
 - run: git checkout HEAD^
@@ -244,12 +249,12 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
 
 ```yaml
 - name: Checkout
-  uses: actions/checkout@v5
+  uses: actions/checkout@v6
   with:
     path: main
 
 - name: Checkout tools repo
-  uses: actions/checkout@v5
+  uses: actions/checkout@v6
   with:
     repository: my-org/my-tools
     path: my-tools
@@ -260,10 +265,10 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
 
 ```yaml
 - name: Checkout
-  uses: actions/checkout@v5
+  uses: actions/checkout@v6
 
 - name: Checkout tools repo
-  uses: actions/checkout@v5
+  uses: actions/checkout@v6
   with:
     repository: my-org/my-tools
     path: my-tools
@@ -274,12 +279,12 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
 
 ```yaml
 - name: Checkout
-  uses: actions/checkout@v5
+  uses: actions/checkout@v6
   with:
     path: main
 
 - name: Checkout private tools
-  uses: actions/checkout@v5
+  uses: actions/checkout@v6
   with:
     repository: my-org/my-private-tools
     token: ${{ secrets.GH_PAT }} # `GH_PAT` is a secret that contains your PAT
@@ -292,7 +297,7 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
 ## Checkout pull request HEAD commit instead of merge commit
 
 ```yaml
-- uses: actions/checkout@v5
+- uses: actions/checkout@v6
   with:
     ref: ${{ github.event.pull_request.head.sha }}
 ```
@@ -308,7 +313,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 ```
 
 ## Push a commit using the built-in token
@@ -319,7 +324,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - run: |
           date > generated.txt
           # Note: the following account information will not work on GHES
@@ -341,7 +346,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           ref: ${{ github.head_ref }}
       - run: |

__test__/git-command-manager.test.ts

@@ -108,7 +108,7 @@ describe('Test fetchDepth and fetchTags options', () => {
     jest.restoreAllMocks()
   })
 
-  it('should call execGit with the correct arguments when fetchDepth is 0 and fetchTags is true', async () => {
+  it('should call execGit with the correct arguments when fetchDepth is 0', async () => {
     jest.spyOn(exec, 'exec').mockImplementation(mockExec)
     const workingDirectory = 'test'
     const lfs = false
@@ -122,45 +122,7 @@ describe('Test fetchDepth and fetchTags options', () => {
     const refSpec = ['refspec1', 'refspec2']
     const options = {
       filter: 'filterValue',
-      fetchDepth: 0,
-      fetchTags: true
-    }
-
-    await git.fetch(refSpec, options)
-
-    expect(mockExec).toHaveBeenCalledWith(
-      expect.any(String),
-      [
-        '-c',
-        'protocol.version=2',
-        'fetch',
-        '--prune',
-        '--no-recurse-submodules',
-        '--filter=filterValue',
-        'origin',
-        'refspec1',
-        'refspec2'
-      ],
-      expect.any(Object)
-    )
-  })
-
-  it('should call execGit with the correct arguments when fetchDepth is 0 and fetchTags is false', async () => {
-    jest.spyOn(exec, 'exec').mockImplementation(mockExec)
-
-    const workingDirectory = 'test'
-    const lfs = false
-    const doSparseCheckout = false
-    git = await commandManager.createCommandManager(
-      workingDirectory,
-      lfs,
-      doSparseCheckout
-    )
-    const refSpec = ['refspec1', 'refspec2']
-    const options = {
-      filter: 'filterValue',
-      fetchDepth: 0,
-      fetchTags: false
+      fetchDepth: 0
     }
 
     await git.fetch(refSpec, options)
@@ -183,7 +145,45 @@ describe('Test fetchDepth and fetchTags options', () => {
     )
   })
 
-  it('should call execGit with the correct arguments when fetchDepth is 1 and fetchTags is false', async () => {
+  it('should call execGit with the correct arguments when fetchDepth is 0 and refSpec includes tags', async () => {
+    jest.spyOn(exec, 'exec').mockImplementation(mockExec)
+
+    const workingDirectory = 'test'
+    const lfs = false
+    const doSparseCheckout = false
+    git = await commandManager.createCommandManager(
+      workingDirectory,
+      lfs,
+      doSparseCheckout
+    )
+    const refSpec = ['refspec1', 'refspec2', '+refs/tags/*:refs/tags/*']
+    const options = {
+      filter: 'filterValue',
+      fetchDepth: 0
+    }
+
+    await git.fetch(refSpec, options)
+
+    expect(mockExec).toHaveBeenCalledWith(
+      expect.any(String),
+      [
+        '-c',
+        'protocol.version=2',
+        'fetch',
+        '--no-tags',
+        '--prune',
+        '--no-recurse-submodules',
+        '--filter=filterValue',
+        'origin',
+        'refspec1',
+        'refspec2',
+        '+refs/tags/*:refs/tags/*'
+      ],
+      expect.any(Object)
+    )
+  })
+
+  it('should call execGit with the correct arguments when fetchDepth is 1', async () => {
     jest.spyOn(exec, 'exec').mockImplementation(mockExec)
 
     const workingDirectory = 'test'
@@ -197,8 +197,7 @@ describe('Test fetchDepth and fetchTags options', () => {
     const refSpec = ['refspec1', 'refspec2']
     const options = {
       filter: 'filterValue',
-      fetchDepth: 1,
-      fetchTags: false
+      fetchDepth: 1
     }
 
     await git.fetch(refSpec, options)
@@ -222,7 +221,7 @@ describe('Test fetchDepth and fetchTags options', () => {
     )
   })
 
-  it('should call execGit with the correct arguments when fetchDepth is 1 and fetchTags is true', async () => {
+  it('should call execGit with the correct arguments when fetchDepth is 1 and refSpec includes tags', async () => {
     jest.spyOn(exec, 'exec').mockImplementation(mockExec)
 
     const workingDirectory = 'test'
@@ -233,11 +232,10 @@ describe('Test fetchDepth and fetchTags options', () => {
       lfs,
       doSparseCheckout
     )
-    const refSpec = ['refspec1', 'refspec2']
+    const refSpec = ['refspec1', 'refspec2', '+refs/tags/*:refs/tags/*']
     const options = {
       filter: 'filterValue',
-      fetchDepth: 1,
-      fetchTags: true
+      fetchDepth: 1
     }
 
     await git.fetch(refSpec, options)
@@ -248,13 +246,15 @@ describe('Test fetchDepth and fetchTags options', () => {
         '-c',
         'protocol.version=2',
         'fetch',
+        '--no-tags',
         '--prune',
         '--no-recurse-submodules',
         '--filter=filterValue',
         '--depth=1',
         'origin',
         'refspec1',
-        'refspec2'
+        'refspec2',
+        '+refs/tags/*:refs/tags/*'
       ],
       expect.any(Object)
     )
@@ -338,7 +338,7 @@ describe('Test fetchDepth and fetchTags options', () => {
     )
   })
 
-  it('should call execGit with the correct arguments when fetchTags is true and showProgress is true', async () => {
+  it('should call execGit with the correct arguments when showProgress is true and refSpec includes tags', async () => {
     jest.spyOn(exec, 'exec').mockImplementation(mockExec)
 
     const workingDirectory = 'test'
@@ -349,10 +349,9 @@ describe('Test fetchDepth and fetchTags options', () => {
       lfs,
       doSparseCheckout
     )
-    const refSpec = ['refspec1', 'refspec2']
+    const refSpec = ['refspec1', 'refspec2', '+refs/tags/*:refs/tags/*']
     const options = {
       filter: 'filterValue',
-      fetchTags: true,
       showProgress: true
     }
 
@@ -364,15 +363,134 @@ describe('Test fetchDepth and fetchTags options', () => {
         '-c',
         'protocol.version=2',
         'fetch',
+        '--no-tags',
         '--prune',
         '--no-recurse-submodules',
         '--progress',
         '--filter=filterValue',
         'origin',
         'refspec1',
-        'refspec2'
+        'refspec2',
+        '+refs/tags/*:refs/tags/*'
       ],
       expect.any(Object)
     )
   })
 })
+
+describe('git user-agent with orchestration ID', () => {
+  beforeEach(async () => {
+    jest.spyOn(fshelper, 'fileExistsSync').mockImplementation(jest.fn())
+    jest.spyOn(fshelper, 'directoryExistsSync').mockImplementation(jest.fn())
+  })
+
+  afterEach(() => {
+    jest.restoreAllMocks()
+    // Clean up environment variable to prevent test pollution
+    delete process.env['ACTIONS_ORCHESTRATION_ID']
+  })
+
+  it('should include orchestration ID in user-agent when ACTIONS_ORCHESTRATION_ID is set', async () => {
+    const orchId = 'test-orch-id-12345'
+    process.env['ACTIONS_ORCHESTRATION_ID'] = orchId
+
+    let capturedEnv: any = null
+    mockExec.mockImplementation((path, args, options) => {
+      if (args.includes('version')) {
+        options.listeners.stdout(Buffer.from('2.18'))
+      }
+      // Capture env on any command
+      capturedEnv = options.env
+      return 0
+    })
+    jest.spyOn(exec, 'exec').mockImplementation(mockExec)
+
+    const workingDirectory = 'test'
+    const lfs = false
+    const doSparseCheckout = false
+    git = await commandManager.createCommandManager(
+      workingDirectory,
+      lfs,
+      doSparseCheckout
+    )
+
+    // Call a git command to trigger env capture after user-agent is set
+    await git.init()
+
+    // Verify the user agent includes the orchestration ID
+    expect(git).toBeDefined()
+    expect(capturedEnv).toBeDefined()
+    expect(capturedEnv['GIT_HTTP_USER_AGENT']).toBe(
+      `git/2.18 (github-actions-checkout) actions_orchestration_id/${orchId}`
+    )
+  })
+
+  it('should sanitize invalid characters in orchestration ID', async () => {
+    const orchId = 'test (with) special/chars'
+    process.env['ACTIONS_ORCHESTRATION_ID'] = orchId
+
+    let capturedEnv: any = null
+    mockExec.mockImplementation((path, args, options) => {
+      if (args.includes('version')) {
+        options.listeners.stdout(Buffer.from('2.18'))
+      }
+      // Capture env on any command
+      capturedEnv = options.env
+      return 0
+    })
+    jest.spyOn(exec, 'exec').mockImplementation(mockExec)
+
+    const workingDirectory = 'test'
+    const lfs = false
+    const doSparseCheckout = false
+    git = await commandManager.createCommandManager(
+      workingDirectory,
+      lfs,
+      doSparseCheckout
+    )
+
+    // Call a git command to trigger env capture after user-agent is set
+    await git.init()
+
+    // Verify the user agent has sanitized orchestration ID (spaces, parentheses, slash replaced)
+    expect(git).toBeDefined()
+    expect(capturedEnv).toBeDefined()
+    expect(capturedEnv['GIT_HTTP_USER_AGENT']).toBe(
+      'git/2.18 (github-actions-checkout) actions_orchestration_id/test__with__special_chars'
+    )
+  })
+
+  it('should not modify user-agent when ACTIONS_ORCHESTRATION_ID is not set', async () => {
+    delete process.env['ACTIONS_ORCHESTRATION_ID']
+
+    let capturedEnv: any = null
+    mockExec.mockImplementation((path, args, options) => {
+      if (args.includes('version')) {
+        options.listeners.stdout(Buffer.from('2.18'))
+      }
+      // Capture env on any command
+      capturedEnv = options.env
+      return 0
+    })
+    jest.spyOn(exec, 'exec').mockImplementation(mockExec)
+
+    const workingDirectory = 'test'
+    const lfs = false
+    const doSparseCheckout = false
+    git = await commandManager.createCommandManager(
+      workingDirectory,
+      lfs,
+      doSparseCheckout
+    )
+
+    // Call a git command to trigger env capture after user-agent is set
+    await git.init()
+
+    // Verify the user agent does NOT contain orchestration ID
+    expect(git).toBeDefined()
+    expect(capturedEnv).toBeDefined()
+    expect(capturedEnv['GIT_HTTP_USER_AGENT']).toBe(
+      'git/2.18 (github-actions-checkout)'
+    )
+  })
+})

__test__/ref-helper.test.ts

@@ -152,7 +152,22 @@ describe('ref-helper tests', () => {
   it('getRefSpec sha + refs/tags/', async () => {
     const refSpec = refHelper.getRefSpec('refs/tags/my-tag', commit)
     expect(refSpec.length).toBe(1)
-    expect(refSpec[0]).toBe(`+${commit}:refs/tags/my-tag`)
+    expect(refSpec[0]).toBe(`+refs/tags/my-tag:refs/tags/my-tag`)
+  })
+
+  it('getRefSpec sha + refs/tags/ with fetchTags', async () => {
+    // When fetchTags is true, only include tags wildcard (specific tag is redundant)
+    const refSpec = refHelper.getRefSpec('refs/tags/my-tag', commit, true)
+    expect(refSpec.length).toBe(1)
+    expect(refSpec[0]).toBe('+refs/tags/*:refs/tags/*')
+  })
+
+  it('getRefSpec sha + refs/heads/ with fetchTags', async () => {
+    // When fetchTags is true, include both the branch refspec and tags wildcard
+    const refSpec = refHelper.getRefSpec('refs/heads/my/branch', commit, true)
+    expect(refSpec.length).toBe(2)
+    expect(refSpec[0]).toBe('+refs/tags/*:refs/tags/*')
+    expect(refSpec[1]).toBe(`+${commit}:refs/remotes/origin/my/branch`)
   })
 
   it('getRefSpec sha only', async () => {
@@ -168,6 +183,14 @@ describe('ref-helper tests', () => {
     expect(refSpec[1]).toBe('+refs/tags/my-ref*:refs/tags/my-ref*')
   })
 
+  it('getRefSpec unqualified ref only with fetchTags', async () => {
+    // When fetchTags is true, skip specific tag pattern since wildcard covers all
+    const refSpec = refHelper.getRefSpec('my-ref', '', true)
+    expect(refSpec.length).toBe(2)
+    expect(refSpec[0]).toBe('+refs/tags/*:refs/tags/*')
+    expect(refSpec[1]).toBe('+refs/heads/my-ref*:refs/remotes/origin/my-ref*')
+  })
+
   it('getRefSpec refs/heads/ only', async () => {
     const refSpec = refHelper.getRefSpec('refs/heads/my/branch', '')
     expect(refSpec.length).toBe(1)
@@ -187,4 +210,21 @@ describe('ref-helper tests', () => {
     expect(refSpec.length).toBe(1)
     expect(refSpec[0]).toBe('+refs/tags/my-tag:refs/tags/my-tag')
   })
+
+  it('getRefSpec refs/tags/ only with fetchTags', async () => {
+    // When fetchTags is true, only include tags wildcard (specific tag is redundant)
+    const refSpec = refHelper.getRefSpec('refs/tags/my-tag', '', true)
+    expect(refSpec.length).toBe(1)
+    expect(refSpec[0]).toBe('+refs/tags/*:refs/tags/*')
+  })
+
+  it('getRefSpec refs/heads/ only with fetchTags', async () => {
+    // When fetchTags is true, include both the branch refspec and tags wildcard
+    const refSpec = refHelper.getRefSpec('refs/heads/my/branch', '', true)
+    expect(refSpec.length).toBe(2)
+    expect(refSpec[0]).toBe('+refs/tags/*:refs/tags/*')
+    expect(refSpec[1]).toBe(
+      '+refs/heads/my/branch:refs/remotes/origin/my/branch'
+    )
+  })
 })

__test__/verify-fetch-tags.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+# Verify tags were fetched
+TAG_COUNT=$(git -C ./fetch-tags-test tag | wc -l)
+if [ "$TAG_COUNT" -eq 0 ]; then
+    echo "Expected tags to be fetched, but found none"
+    exit 1
+fi
+echo "Found $TAG_COUNT tags"

__test__/verify-worktree.sh

@@ -0,0 +1,51 @@
+#!/bin/bash
+set -e
+
+# Verify worktree credentials
+# This test verifies that git credentials work in worktrees created after checkout
+# Usage: verify-worktree.sh <checkout-path> <worktree-name>
+
+CHECKOUT_PATH="$1"
+WORKTREE_NAME="$2"
+
+if [ -z "$CHECKOUT_PATH" ] || [ -z "$WORKTREE_NAME" ]; then
+  echo "Usage: verify-worktree.sh <checkout-path> <worktree-name>"
+  exit 1
+fi
+
+cd "$CHECKOUT_PATH"
+
+# Add safe directory for container environments
+git config --global --add safe.directory "*" 2>/dev/null || true
+
+# Show the includeIf configuration
+echo "Git config includeIf entries:"
+git config --list --show-origin | grep -i include || true
+
+# Create the worktree
+echo "Creating worktree..."
+git worktree add "../$WORKTREE_NAME" HEAD --detach
+
+# Change to worktree directory
+cd "../$WORKTREE_NAME"
+
+# Verify we're in a worktree
+echo "Verifying worktree gitdir:"
+cat .git
+
+# Verify credentials are available in worktree by checking extraheader is configured
+echo "Checking credentials in worktree..."
+if git config --list --show-origin | grep -q "extraheader"; then
+  echo "Credentials are configured in worktree"
+else
+  echo "ERROR: Credentials are NOT configured in worktree"
+  echo "Full git config:"
+  git config --list --show-origin
+  exit 1
+fi
+
+# Verify fetch works in the worktree
+echo "Fetching in worktree..."
+git fetch origin
+
+echo "Worktree credentials test passed!"

action.yml

@@ -98,6 +98,10 @@ inputs:
   github-server-url:
     description: The base URL for the GitHub instance that you are trying to clone from, will use environment defaults to fetch from the same instance that the workflow is running from unless specified. Example URLs are https://github.com or https://my-ghes-server.example.com
     required: false
+  repo-sha256:
+    description: 'Set Git object format to "sha256" when initializing a Git repository.'
+    required: false
+    default: false
 outputs:
   ref:
     description: 'The branch, tag or SHA that was checked out'

dist/index.js

@@ -412,6 +412,9 @@ class GitAuthHelper {
                 // Configure host includeIf
                 const hostIncludeKey = `includeIf.gitdir:${gitDir}.path`;
                 yield this.git.config(hostIncludeKey, credentialsConfigPath);
+                // Configure host includeIf for worktrees
+                const hostWorktreeIncludeKey = `includeIf.gitdir:${gitDir}/worktrees/*.path`;
+                yield this.git.config(hostWorktreeIncludeKey, credentialsConfigPath);
                 // Container git directory
                 const workingDirectory = this.git.getWorkingDirectory();
                 const githubWorkspace = process.env['GITHUB_WORKSPACE'];
@@ -424,6 +427,9 @@ class GitAuthHelper {
                 // Configure container includeIf
                 const containerIncludeKey = `includeIf.gitdir:${containerGitDir}.path`;
                 yield this.git.config(containerIncludeKey, containerCredentialsPath);
+                // Configure container includeIf for worktrees
+                const containerWorktreeIncludeKey = `includeIf.gitdir:${containerGitDir}/worktrees/*.path`;
+                yield this.git.config(containerWorktreeIncludeKey, containerCredentialsPath);
             }
         });
     }
@@ -647,7 +653,6 @@ const fs = __importStar(__nccwpck_require__(7147));
 const fshelper = __importStar(__nccwpck_require__(7219));
 const io = __importStar(__nccwpck_require__(7436));
 const path = __importStar(__nccwpck_require__(1017));
-const refHelper = __importStar(__nccwpck_require__(8601));
 const regexpHelper = __importStar(__nccwpck_require__(3120));
 const retryHelper = __importStar(__nccwpck_require__(2155));
 const git_version_1 = __nccwpck_require__(3142);
@@ -825,9 +830,9 @@ class GitCommandManager {
     fetch(refSpec, options) {
         return __awaiter(this, void 0, void 0, function* () {
             const args = ['-c', 'protocol.version=2', 'fetch'];
-            if (!refSpec.some(x => x === refHelper.tagsRefSpec) && !options.fetchTags) {
-                args.push('--no-tags');
-            }
+            // Always use --no-tags for explicit control over tag fetching
+            // Tags are fetched explicitly via refspec when needed
+            args.push('--no-tags');
             args.push('--prune', '--no-recurse-submodules');
             if (options.showProgress) {
                 args.push('--progress');
@@ -891,9 +896,14 @@ class GitCommandManager {
     getWorkingDirectory() {
         return this.workingDirectory;
     }
-    init() {
+    init(repoSHA256) {
         return __awaiter(this, void 0, void 0, function* () {
-            yield this.execGit(['init', this.workingDirectory]);
+            const args = ['init'];
+            if (repoSHA256) {
+                args.push(`--object-format=sha256`);
+            }
+            args.push(this.workingDirectory);
+            yield this.execGit(args);
         });
     }
     isDetached() {
@@ -1200,7 +1210,17 @@ class GitCommandManager {
                 }
             }
             // Set the user agent
-            const gitHttpUserAgent = `git/${this.gitVersion} (github-actions-checkout)`;
+            let gitHttpUserAgent = `git/${this.gitVersion} (github-actions-checkout)`;
+            // Append orchestration ID if set
+            const orchId = process.env['ACTIONS_ORCHESTRATION_ID'];
+            if (orchId) {
+                // Sanitize the orchestration ID to ensure it contains only valid characters
+                // Valid characters: 0-9, a-z, _, -, .
+                const sanitizedId = orchId.replace(/[^a-z0-9_.-]/gi, '_');
+                if (sanitizedId) {
+                    gitHttpUserAgent = `${gitHttpUserAgent} actions_orchestration_id/${sanitizedId}`;
+                }
+            }
             core.debug(`Set git useragent to: ${gitHttpUserAgent}`);
             this.gitEnv['GIT_HTTP_USER_AGENT'] = gitHttpUserAgent;
         });
@@ -1472,7 +1492,7 @@ function getSource(settings) {
             // Initialize the repository
             if (!fsHelper.directoryExistsSync(path.join(settings.repositoryPath, '.git'))) {
                 core.startGroup('Initializing the repository');
-                yield git.init();
+                yield git.init(settings.repoSHA256);
                 yield git.remoteAdd('origin', repositoryUrl);
                 core.endGroup();
             }
@@ -1523,13 +1543,26 @@ function getSource(settings) {
                 if (!(yield refHelper.testRef(git, settings.ref, settings.commit))) {
                     refSpec = refHelper.getRefSpec(settings.ref, settings.commit);
                     yield git.fetch(refSpec, fetchOptions);
+                    // Verify the ref now matches. For branches, the targeted fetch above brings
+                    // in the specific commit. For tags (fetched by ref), this will fail if
+                    // the tag was moved after the workflow was triggered.
+                    if (!(yield refHelper.testRef(git, settings.ref, settings.commit))) {
+                        throw new Error(`The ref '${settings.ref}' does not point to the expected commit '${settings.commit}'. ` +
+                            `The ref may have been updated after the workflow was triggered.`);
+                    }
                 }
             }
             else {
                 fetchOptions.fetchDepth = settings.fetchDepth;
-                fetchOptions.fetchTags = settings.fetchTags;
-                const refSpec = refHelper.getRefSpec(settings.ref, settings.commit);
+                const refSpec = refHelper.getRefSpec(settings.ref, settings.commit, settings.fetchTags);
                 yield git.fetch(refSpec, fetchOptions);
+                // For tags, verify the ref still points to the expected commit.
+                // Tags are fetched by ref (not commit), so if a tag was moved after the
+                // workflow was triggered, we would silently check out the wrong commit.
+                if (!(yield refHelper.testRef(git, settings.ref, settings.commit))) {
+                    throw new Error(`The ref '${settings.ref}' does not point to the expected commit '${settings.commit}'. ` +
+                        `The ref may have been updated after the workflow was triggered.`);
+                }
             }
             core.endGroup();
             // Checkout info
@@ -2067,6 +2100,10 @@ function getInputs() {
         // Determine the GitHub URL that the repository is being hosted from
         result.githubServerUrl = core.getInput('github-server-url');
         core.debug(`GitHub Host URL = ${result.githubServerUrl}`);
+        // Set Git object format to "sha256" when initializing a Git repository.
+        result.repoSHA256 =
+            (core.getInput('repo-sha256') || 'false').toUpperCase() === 'TRUE';
+        core.debug(`Repo object format sha256 = ${result.repoSHA256}`);
         return result;
     });
 }
@@ -2268,53 +2305,67 @@ function getRefSpecForAllHistory(ref, commit) {
     }
     return result;
 }
-function getRefSpec(ref, commit) {
+function getRefSpec(ref, commit, fetchTags) {
     if (!ref && !commit) {
         throw new Error('Args ref and commit cannot both be empty');
     }
     const upperRef = (ref || '').toUpperCase();
+    const result = [];
+    // When fetchTags is true, always include the tags refspec
+    if (fetchTags) {
+        result.push(exports.tagsRefSpec);
+    }
     // SHA
     if (commit) {
         // refs/heads
         if (upperRef.startsWith('REFS/HEADS/')) {
             const branch = ref.substring('refs/heads/'.length);
-            return [`+${commit}:refs/remotes/origin/${branch}`];
+            result.push(`+${commit}:refs/remotes/origin/${branch}`);
         }
         // refs/pull/
         else if (upperRef.startsWith('REFS/PULL/')) {
             const branch = ref.substring('refs/pull/'.length);
-            return [`+${commit}:refs/remotes/pull/${branch}`];
+            result.push(`+${commit}:refs/remotes/pull/${branch}`);
         }
         // refs/tags/
         else if (upperRef.startsWith('REFS/TAGS/')) {
-            return [`+${commit}:${ref}`];
+            if (!fetchTags) {
+                result.push(`+${ref}:${ref}`);
+            }
         }
         // Otherwise no destination ref
         else {
-            return [commit];
+            result.push(commit);
         }
     }
     // Unqualified ref, check for a matching branch or tag
     else if (!upperRef.startsWith('REFS/')) {
-        return [
-            `+refs/heads/${ref}*:refs/remotes/origin/${ref}*`,
-            `+refs/tags/${ref}*:refs/tags/${ref}*`
-        ];
+        result.push(`+refs/heads/${ref}*:refs/remotes/origin/${ref}*`);
+        if (!fetchTags) {
+            result.push(`+refs/tags/${ref}*:refs/tags/${ref}*`);
+        }
     }
     // refs/heads/
     else if (upperRef.startsWith('REFS/HEADS/')) {
         const branch = ref.substring('refs/heads/'.length);
-        return [`+${ref}:refs/remotes/origin/${branch}`];
+        result.push(`+${ref}:refs/remotes/origin/${branch}`);
     }
     // refs/pull/
     else if (upperRef.startsWith('REFS/PULL/')) {
         const branch = ref.substring('refs/pull/'.length);
-        return [`+${ref}:refs/remotes/pull/${branch}`];
+        result.push(`+${ref}:refs/remotes/pull/${branch}`);
     }
     // refs/tags/
-    else {
-        return [`+${ref}:${ref}`];
+    else if (upperRef.startsWith('REFS/TAGS/')) {
+        if (!fetchTags) {
+            result.push(`+${ref}:${ref}`);
+        }
     }
+    // Other refs
+    else {
+        result.push(`+${ref}:${ref}`);
+    }
+    return result;
 }
 /**
  * Tests whether the initial fetch created the ref at the expected commit
@@ -2350,7 +2401,9 @@ function testRef(git, ref, commit) {
         // refs/tags/
         else if (upperRef.startsWith('REFS/TAGS/')) {
             const tagName = ref.substring('refs/tags/'.length);
-            return ((yield git.tagExists(tagName)) && commit === (yield git.revParse(ref)));
+            // Use ^{commit} to dereference annotated tags to their underlying commit
+            return ((yield git.tagExists(tagName)) &&
+                commit === (yield git.revParse(`${ref}^{commit}`)));
         }
         // Unexpected
         else {

src/git-auth-helper.ts

@@ -374,6 +374,10 @@ class GitAuthHelper {
       const hostIncludeKey = `includeIf.gitdir:${gitDir}.path`
       await this.git.config(hostIncludeKey, credentialsConfigPath)
 
+      // Configure host includeIf for worktrees
+      const hostWorktreeIncludeKey = `includeIf.gitdir:${gitDir}/worktrees/*.path`
+      await this.git.config(hostWorktreeIncludeKey, credentialsConfigPath)
+
       // Container git directory
       const workingDirectory = this.git.getWorkingDirectory()
       const githubWorkspace = process.env['GITHUB_WORKSPACE']
@@ -395,6 +399,13 @@ class GitAuthHelper {
       // Configure container includeIf
       const containerIncludeKey = `includeIf.gitdir:${containerGitDir}.path`
       await this.git.config(containerIncludeKey, containerCredentialsPath)
+
+      // Configure container includeIf for worktrees
+      const containerWorktreeIncludeKey = `includeIf.gitdir:${containerGitDir}/worktrees/*.path`
+      await this.git.config(
+        containerWorktreeIncludeKey,
+        containerCredentialsPath
+      )
     }
   }
 

src/git-command-manager.ts

@@ -37,14 +37,13 @@ export interface IGitCommandManager {
     options: {
       filter?: string
       fetchDepth?: number
-      fetchTags?: boolean
       showProgress?: boolean
     }
   ): Promise<void>
   getDefaultBranch(repositoryUrl: string): Promise<string>
   getSubmoduleConfigPaths(recursive: boolean): Promise<string[]>
   getWorkingDirectory(): string
-  init(): Promise<void>
+  init(repoSHA256?: boolean): Promise<void>
   isDetached(): Promise<boolean>
   lfsFetch(ref: string): Promise<void>
   lfsInstall(): Promise<void>
@@ -280,14 +279,13 @@ class GitCommandManager {
     options: {
       filter?: string
       fetchDepth?: number
-      fetchTags?: boolean
       showProgress?: boolean
     }
   ): Promise<void> {
     const args = ['-c', 'protocol.version=2', 'fetch']
-    if (!refSpec.some(x => x === refHelper.tagsRefSpec) && !options.fetchTags) {
-      args.push('--no-tags')
-    }
+    // Always use --no-tags for explicit control over tag fetching
+    // Tags are fetched explicitly via refspec when needed
+    args.push('--no-tags')
 
     args.push('--prune', '--no-recurse-submodules')
     if (options.showProgress) {
@@ -366,8 +364,13 @@ class GitCommandManager {
     return this.workingDirectory
   }
 
-  async init(): Promise<void> {
-    await this.execGit(['init', this.workingDirectory])
+  async init(repoSHA256?: boolean): Promise<void> {
+    const args = ['init']
+    if (repoSHA256) {
+      args.push(`--object-format=sha256`)
+    }
+    args.push(this.workingDirectory)
+    await this.execGit(args)
   }
 
   async isDetached(): Promise<boolean> {
@@ -730,7 +733,19 @@ class GitCommandManager {
       }
     }
     // Set the user agent
-    const gitHttpUserAgent = `git/${this.gitVersion} (github-actions-checkout)`
+    let gitHttpUserAgent = `git/${this.gitVersion} (github-actions-checkout)`
+
+    // Append orchestration ID if set
+    const orchId = process.env['ACTIONS_ORCHESTRATION_ID']
+    if (orchId) {
+      // Sanitize the orchestration ID to ensure it contains only valid characters
+      // Valid characters: 0-9, a-z, _, -, .
+      const sanitizedId = orchId.replace(/[^a-z0-9_.-]/gi, '_')
+      if (sanitizedId) {
+        gitHttpUserAgent = `${gitHttpUserAgent} actions_orchestration_id/${sanitizedId}`
+      }
+    }
+
     core.debug(`Set git useragent to: ${gitHttpUserAgent}`)
     this.gitEnv['GIT_HTTP_USER_AGENT'] = gitHttpUserAgent
   }

src/git-source-provider.ts

@@ -110,7 +110,7 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
       !fsHelper.directoryExistsSync(path.join(settings.repositoryPath, '.git'))
     ) {
       core.startGroup('Initializing the repository')
-      await git.init()
+      await git.init(settings.repoSHA256)
       await git.remoteAdd('origin', repositoryUrl)
       core.endGroup()
     }
@@ -159,7 +159,6 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
     const fetchOptions: {
       filter?: string
       fetchDepth?: number
-      fetchTags?: boolean
       showProgress?: boolean
     } = {}
 
@@ -182,12 +181,35 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
       if (!(await refHelper.testRef(git, settings.ref, settings.commit))) {
         refSpec = refHelper.getRefSpec(settings.ref, settings.commit)
         await git.fetch(refSpec, fetchOptions)
+
+        // Verify the ref now matches. For branches, the targeted fetch above brings
+        // in the specific commit. For tags (fetched by ref), this will fail if
+        // the tag was moved after the workflow was triggered.
+        if (!(await refHelper.testRef(git, settings.ref, settings.commit))) {
+          throw new Error(
+            `The ref '${settings.ref}' does not point to the expected commit '${settings.commit}'. ` +
+              `The ref may have been updated after the workflow was triggered.`
+          )
+        }
       }
     } else {
       fetchOptions.fetchDepth = settings.fetchDepth
-      fetchOptions.fetchTags = settings.fetchTags
-      const refSpec = refHelper.getRefSpec(settings.ref, settings.commit)
+      const refSpec = refHelper.getRefSpec(
+        settings.ref,
+        settings.commit,
+        settings.fetchTags
+      )
       await git.fetch(refSpec, fetchOptions)
+
+      // For tags, verify the ref still points to the expected commit.
+      // Tags are fetched by ref (not commit), so if a tag was moved after the
+      // workflow was triggered, we would silently check out the wrong commit.
+      if (!(await refHelper.testRef(git, settings.ref, settings.commit))) {
+        throw new Error(
+          `The ref '${settings.ref}' does not point to the expected commit '${settings.commit}'. ` +
+            `The ref may have been updated after the workflow was triggered.`
+        )
+      }
     }
     core.endGroup()
 

src/git-source-settings.ts

@@ -118,4 +118,9 @@ export interface IGitSourceSettings {
    * User override on the GitHub Server/Host URL that hosts the repository to be cloned
    */
   githubServerUrl: string | undefined
+
+  /**
+   * Set Git object format to "sha256" when initializing a Git repository
+   */
+  repoSHA256: boolean
 }

src/input-helper.ts

@@ -161,5 +161,10 @@ export async function getInputs(): Promise<IGitSourceSettings> {
   result.githubServerUrl = core.getInput('github-server-url')
   core.debug(`GitHub Host URL = ${result.githubServerUrl}`)
 
+  // Set Git object format to "sha256" when initializing a Git repository.
+  result.repoSHA256 =
+    (core.getInput('repo-sha256') || 'false').toUpperCase() === 'TRUE'
+  core.debug(`Repo object format sha256 = ${result.repoSHA256}`)
+
   return result
 }

src/misc/generate-docs.ts

@@ -120,7 +120,7 @@ function updateUsage(
 }
 
 updateUsage(
-  'actions/checkout@v5',
+  'actions/checkout@v6',
   path.join(__dirname, '..', '..', 'action.yml'),
   path.join(__dirname, '..', '..', 'README.md')
 )

src/ref-helper.ts

@@ -76,55 +76,75 @@ export function getRefSpecForAllHistory(ref: string, commit: string): string[] {
   return result
 }
 
-export function getRefSpec(ref: string, commit: string): string[] {
+export function getRefSpec(
+  ref: string,
+  commit: string,
+  fetchTags?: boolean
+): string[] {
   if (!ref && !commit) {
     throw new Error('Args ref and commit cannot both be empty')
   }
 
   const upperRef = (ref || '').toUpperCase()
+  const result: string[] = []
+
+  // When fetchTags is true, always include the tags refspec
+  if (fetchTags) {
+    result.push(tagsRefSpec)
+  }
 
   // SHA
   if (commit) {
     // refs/heads
     if (upperRef.startsWith('REFS/HEADS/')) {
       const branch = ref.substring('refs/heads/'.length)
-      return [`+${commit}:refs/remotes/origin/${branch}`]
+      result.push(`+${commit}:refs/remotes/origin/${branch}`)
     }
     // refs/pull/
     else if (upperRef.startsWith('REFS/PULL/')) {
       const branch = ref.substring('refs/pull/'.length)
-      return [`+${commit}:refs/remotes/pull/${branch}`]
+      result.push(`+${commit}:refs/remotes/pull/${branch}`)
     }
     // refs/tags/
     else if (upperRef.startsWith('REFS/TAGS/')) {
-      return [`+${commit}:${ref}`]
+      if (!fetchTags) {
+        result.push(`+${ref}:${ref}`)
+      }
     }
     // Otherwise no destination ref
     else {
-      return [commit]
+      result.push(commit)
     }
   }
   // Unqualified ref, check for a matching branch or tag
   else if (!upperRef.startsWith('REFS/')) {
-    return [
-      `+refs/heads/${ref}*:refs/remotes/origin/${ref}*`,
-      `+refs/tags/${ref}*:refs/tags/${ref}*`
-    ]
+    result.push(`+refs/heads/${ref}*:refs/remotes/origin/${ref}*`)
+    if (!fetchTags) {
+      result.push(`+refs/tags/${ref}*:refs/tags/${ref}*`)
+    }
   }
   // refs/heads/
   else if (upperRef.startsWith('REFS/HEADS/')) {
     const branch = ref.substring('refs/heads/'.length)
-    return [`+${ref}:refs/remotes/origin/${branch}`]
+    result.push(`+${ref}:refs/remotes/origin/${branch}`)
   }
   // refs/pull/
   else if (upperRef.startsWith('REFS/PULL/')) {
     const branch = ref.substring('refs/pull/'.length)
-    return [`+${ref}:refs/remotes/pull/${branch}`]
+    result.push(`+${ref}:refs/remotes/pull/${branch}`)
   }
   // refs/tags/
-  else {
-    return [`+${ref}:${ref}`]
+  else if (upperRef.startsWith('REFS/TAGS/')) {
+    if (!fetchTags) {
+      result.push(`+${ref}:${ref}`)
+    }
   }
+  // Other refs
+  else {
+    result.push(`+${ref}:${ref}`)
+  }
+
+  return result
 }
 
 /**
@@ -170,8 +190,10 @@ export async function testRef(
   // refs/tags/
   else if (upperRef.startsWith('REFS/TAGS/')) {
     const tagName = ref.substring('refs/tags/'.length)
+    // Use ^{commit} to dereference annotated tags to their underlying commit
     return (
-      (await git.tagExists(tagName)) && commit === (await git.revParse(ref))
+      (await git.tagExists(tagName)) &&
+      commit === (await git.revParse(`${ref}^{commit}`))
     )
   }
   // Unexpected