feat(checkout): Add `--reference to Local Repo

README.md

@@ -126,6 +126,11 @@ 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: ''
+
+    # Path to a local bare git reference repository to minimize network usage. If the
+    # provided path does not exist, it will be ignored with a logged message. See
+    # https://git-scm.com/docs/git-clone#Documentation/git-clone.txt---referenceif-abortnew-repository for more details.
+    reference: ''
 ```
 <!-- end usage -->
 

__test__/git-auth-helper.test.ts

@@ -732,6 +732,7 @@ async function setup(testName: string): Promise<void> {
     sparseCheckoutNonConeMode: jest.fn(),
     checkout: jest.fn(),
     checkoutDetach: jest.fn(),
+    referenceAdd: jest.fn(),
     config: jest.fn(
       async (key: string, value: string, globalConfig?: boolean) => {
         const configPath = globalConfig
@@ -824,7 +825,8 @@ async function setup(testName: string): Promise<void> {
     sshUser: '',
     workflowOrganizationId: 123456,
     setSafeDirectory: true,
-    githubServerUrl: githubServerUrl
+    githubServerUrl: githubServerUrl,
+    reference: undefined
   }
 }
 

__test__/git-directory-helper.test.ts

@@ -467,6 +467,7 @@ async function setup(testName: string): Promise<void> {
     sparseCheckoutNonConeMode: jest.fn(),
     checkout: jest.fn(),
     checkoutDetach: jest.fn(),
+    referenceAdd: jest.fn(),
     config: jest.fn(),
     configExists: jest.fn(),
     fetch: jest.fn(),

__test__/input-helper.test.ts

@@ -91,6 +91,7 @@ describe('input-helper tests', () => {
     expect(settings.repositoryOwner).toBe('some-owner')
     expect(settings.repositoryPath).toBe(gitHubWorkspace)
     expect(settings.setSafeDirectory).toBe(true)
+    expect(settings.reference).toBe(undefined)
   })
 
   it('qualifies ref', async () => {

action.yml

@@ -1,109 +1,115 @@
-name: 'Checkout'
-description: 'Checkout a Git repository at a particular version'
-inputs:
-  repository:
-    description: 'Repository name with owner. For example, actions/checkout'
-    default: ${{ github.repository }}
-  ref:
-    description: >
-      The branch, tag or SHA to checkout. When checking out the repository that
-      triggered a workflow, this defaults to the reference or SHA for that
-      event.  Otherwise, uses the default branch.
-  token:
-    description: >
-      Personal access token (PAT) used to fetch the repository. The PAT is configured
-      with the local git config, which enables your scripts to run authenticated git
-      commands. The post-job step removes the PAT.
-
-
-      We recommend using a service account with the least permissions necessary.
-      Also when generating a new PAT, select the least scopes necessary.
-
-
-      [Learn more about creating and using encrypted secrets](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/creating-and-using-encrypted-secrets)
-    default: ${{ github.token }}
-  ssh-key:
-    description: >
-      SSH key used to fetch the repository. The SSH key is configured with the local
-      git config, which enables your scripts to run authenticated git commands.
-      The post-job step removes the SSH key.
-
-
-      We recommend using a service account with the least permissions necessary.
-
-
-      [Learn more about creating and using
-      encrypted secrets](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/creating-and-using-encrypted-secrets)
-  ssh-known-hosts:
-    description: >
-      Known hosts in addition to the user and global host key database. The public
-      SSH keys for a host may be obtained using the utility `ssh-keyscan`. For example,
-      `ssh-keyscan github.com`. The public key for github.com is always implicitly added.
-  ssh-strict:
-    description: >
-      Whether to perform strict host key checking. When true, adds the options `StrictHostKeyChecking=yes`
-      and `CheckHostIP=no` to the SSH command line. Use the input `ssh-known-hosts` to
-      configure additional hosts.
-    default: true
-  ssh-user:
-    description: >
-      The user to use when connecting to the remote SSH host. By default 'git' is used.
-    default: git
-  persist-credentials:
-    description: 'Whether to configure the token or SSH key with the local git config'
-    default: true
-  path:
-    description: 'Relative path under $GITHUB_WORKSPACE to place the repository'
-  clean:
-    description: 'Whether to execute `git clean -ffdx && git reset --hard HEAD` before fetching'
-    default: true
-  filter:
-    description: >
-      Partially clone against a given filter.
-      Overrides sparse-checkout if set.
-    default: null
-  sparse-checkout:
-    description: >
-      Do a sparse checkout on given patterns.
-      Each pattern should be separated with new lines.
-    default: null
-  sparse-checkout-cone-mode:
-    description: >
-      Specifies whether to use cone-mode when doing a sparse checkout.
-    default: true
-  fetch-depth:
-    description: 'Number of commits to fetch. 0 indicates all history for all branches and tags.'
-    default: 1
-  fetch-tags:
-    description: 'Whether to fetch tags, even if fetch-depth > 0.'
-    default: false
-  show-progress:
-    description: 'Whether to show progress status output when fetching.'
-    default: true
-  lfs:
-    description: 'Whether to download Git-LFS files'
-    default: false
-  submodules:
-    description: >
-      Whether to checkout submodules: `true` to checkout submodules or `recursive` to
-      recursively checkout submodules.
-
-
-      When the `ssh-key` input is not provided, SSH URLs beginning with `git@github.com:` are
-      converted to HTTPS.
-    default: false
-  set-safe-directory:
-    description: Add repository path as safe.directory for Git global config by running `git config --global --add safe.directory <path>`
-    default: true
-  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
-outputs:
-  ref:
-    description: 'The branch, tag or SHA that was checked out'
-  commit:
-    description: 'The commit SHA that was checked out'
-runs:
-  using: node20
-  main: dist/index.js
-  post: dist/index.js
+name: 'Checkout'
+description: 'Checkout a Git repository at a particular version'
+inputs:
+  repository:
+    description: 'Repository name with owner. For example, actions/checkout'
+    default: ${{ github.repository }}
+  ref:
+    description: >
+      The branch, tag or SHA to checkout. When checking out the repository that
+      triggered a workflow, this defaults to the reference or SHA for that
+      event.  Otherwise, uses the default branch.
+  token:
+    description: >
+      Personal access token (PAT) used to fetch the repository. The PAT is configured
+      with the local git config, which enables your scripts to run authenticated git
+      commands. The post-job step removes the PAT.
+
+
+      We recommend using a service account with the least permissions necessary.
+      Also when generating a new PAT, select the least scopes necessary.
+
+
+      [Learn more about creating and using encrypted secrets](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/creating-and-using-encrypted-secrets)
+    default: ${{ github.token }}
+  ssh-key:
+    description: >
+      SSH key used to fetch the repository. The SSH key is configured with the local
+      git config, which enables your scripts to run authenticated git commands.
+      The post-job step removes the SSH key.
+
+
+      We recommend using a service account with the least permissions necessary.
+
+
+      [Learn more about creating and using
+      encrypted secrets](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/creating-and-using-encrypted-secrets)
+  ssh-known-hosts:
+    description: >
+      Known hosts in addition to the user and global host key database. The public
+      SSH keys for a host may be obtained using the utility `ssh-keyscan`. For example,
+      `ssh-keyscan github.com`. The public key for github.com is always implicitly added.
+  ssh-strict:
+    description: >
+      Whether to perform strict host key checking. When true, adds the options `StrictHostKeyChecking=yes`
+      and `CheckHostIP=no` to the SSH command line. Use the input `ssh-known-hosts` to
+      configure additional hosts.
+    default: true
+  ssh-user:
+    description: >
+      The user to use when connecting to the remote SSH host. By default 'git' is used.
+    default: git
+  persist-credentials:
+    description: 'Whether to configure the token or SSH key with the local git config'
+    default: true
+  path:
+    description: 'Relative path under $GITHUB_WORKSPACE to place the repository'
+  clean:
+    description: 'Whether to execute `git clean -ffdx && git reset --hard HEAD` before fetching'
+    default: true
+  filter:
+    description: >
+      Partially clone against a given filter.
+      Overrides sparse-checkout if set.
+    default: null
+  sparse-checkout:
+    description: >
+      Do a sparse checkout on given patterns.
+      Each pattern should be separated with new lines.
+    default: null
+  sparse-checkout-cone-mode:
+    description: >
+      Specifies whether to use cone-mode when doing a sparse checkout.
+    default: true
+  fetch-depth:
+    description: 'Number of commits to fetch. 0 indicates all history for all branches and tags.'
+    default: 1
+  fetch-tags:
+    description: 'Whether to fetch tags, even if fetch-depth > 0.'
+    default: false
+  show-progress:
+    description: 'Whether to show progress status output when fetching.'
+    default: true
+  lfs:
+    description: 'Whether to download Git-LFS files'
+    default: false
+  submodules:
+    description: >
+      Whether to checkout submodules: `true` to checkout submodules or `recursive` to
+      recursively checkout submodules.
+
+
+      When the `ssh-key` input is not provided, SSH URLs beginning with `git@github.com:` are
+      converted to HTTPS.
+    default: false
+  set-safe-directory:
+    description: Add repository path as safe.directory for Git global config by running `git config --global --add safe.directory <path>`
+    default: true
+  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
+  reference:
+    description: >
+      Path to a local bare git reference repository to minimize network usage.
+      If the provided path does not exist, it will be ignored with a logged message.
+      See https://git-scm.com/docs/git-clone#Documentation/git-clone.txt---referenceif-abortnew-repository for more details.
+    required: false
+outputs:
+  ref:
+    description: 'The branch, tag or SHA that was checked out'
+  commit:
+    description: 'The commit SHA that was checked out'
+runs:
+  using: node20
+  main: dist/index.js
+  post: dist/index.js

dist/index.js

@@ -627,6 +627,12 @@ class GitCommandManager {
             yield this.execGit(args);
         });
     }
+    referenceAdd(reference) {
+        return __awaiter(this, void 0, void 0, function* () {
+            const alternatesPath = path.join(this.workingDirectory, '.git', 'objects', 'info', 'alternates');
+            yield fs.promises.appendFile(alternatesPath, `${path.join(reference, 'objects')}\n`);
+        });
+    }
     config(configKey, configValue, globalConfig, add) {
         return __awaiter(this, void 0, void 0, function* () {
             const args = ['config', globalConfig ? '--global' : '--local'];
@@ -1241,6 +1247,18 @@ function getSource(settings) {
                 yield git.remoteAdd('origin', repositoryUrl);
                 core.endGroup();
             }
+            // Reference repository
+            if (settings.reference) {
+                if (fsHelper.directoryExistsSync(settings.reference)) {
+                    core.startGroup('Setting up reference repository');
+                    core.info(`Using reference repository at ${settings.reference}`);
+                    yield git.referenceAdd(settings.reference);
+                    core.endGroup();
+                }
+                else {
+                    core.warning(`Reference repository '${settings.reference}' does not exist, skipping`);
+                }
+            }
             // Disable automatic garbage collection
             core.startGroup('Disabling automatic garbage collection');
             if (!(yield git.tryDisableAutomaticGarbageCollection())) {
@@ -1832,6 +1850,9 @@ 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}`);
+        // Reference repository
+        result.reference = core.getInput('reference');
+        core.debug(`reference = ${result.reference}`);
         return result;
     });
 }

src/git-command-manager.ts

@@ -24,6 +24,7 @@ export interface IGitCommandManager {
   sparseCheckoutNonConeMode(sparseCheckout: string[]): Promise<void>
   checkout(ref: string, startPoint: string): Promise<void>
   checkoutDetach(): Promise<void>
+  referenceAdd(reference: string): Promise<void>
   config(
     configKey: string,
     configValue: string,
@@ -219,6 +220,20 @@ class GitCommandManager {
     await this.execGit(args)
   }
 
+  async referenceAdd(reference: string): Promise<void> {
+    const alternatesPath = path.join(
+      this.workingDirectory,
+      '.git',
+      'objects',
+      'info',
+      'alternates'
+    )
+    await fs.promises.appendFile(
+      alternatesPath,
+      `${path.join(reference, 'objects')}\n`
+    )
+  }
+
   async config(
     configKey: string,
     configValue: string,

src/git-source-provider.ts

@@ -115,6 +115,20 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
       core.endGroup()
     }
 
+    // Reference repository
+    if (settings.reference) {
+      if (fsHelper.directoryExistsSync(settings.reference)) {
+        core.startGroup('Setting up reference repository')
+        core.info(`Using reference repository at ${settings.reference}`)
+        await git.referenceAdd(settings.reference)
+        core.endGroup()
+      } else {
+        core.warning(
+          `Reference repository '${settings.reference}' does not exist, skipping`
+        )
+      }
+    }
+
     // Disable automatic garbage collection
     core.startGroup('Disabling automatic garbage collection')
     if (!(await git.tryDisableAutomaticGarbageCollection())) {

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
+
+  /**
+   * Path to a local bare git reference repository to minimize network usage
+   */
+  reference: string | undefined
 }

src/input-helper.ts

@@ -161,5 +161,9 @@ export async function getInputs(): Promise<IGitSourceSettings> {
   result.githubServerUrl = core.getInput('github-server-url')
   core.debug(`GitHub Host URL = ${result.githubServerUrl}`)
 
+  // Reference repository
+  result.reference = core.getInput('reference')
+  core.debug(`reference = ${result.reference}`)
+
   return result
 }