Add objectFormat setting to allow init()ing a repo with sha256

Author: yangskyboxlabs

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: ''
+
+    # Use the given object format when creating local repository.  Specifically, use
+    # 'sha256' to checkout a SHA-256 repository.
+    # Defualt: null
+    object-format: ''
 ```
 <!-- end usage -->
 
@@ -143,6 +148,7 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
 - [Checkout pull request HEAD commit instead of merge commit](#Checkout-pull-request-HEAD-commit-instead-of-merge-commit)
 - [Checkout pull request on closed event](#Checkout-pull-request-on-closed-event)
 - [Push a commit using the built-in token](#Push-a-commit-using-the-built-in-token)
+- [Checkout SHA-256 repository](#checkout-sha-256-repository)
 
 ## Fetch only the root files
 
@@ -288,6 +294,14 @@ jobs:
 ```
 *NOTE:* The user email is `{user.id}+{user.login}@users.noreply.github.com`. See users API: https://api.github.com/users/github-actions%5Bbot%5D
 
+## Checkout SHA-256 repository
+
+```yaml
+- uses: actions/checkout@v4
+  with:
+    object-format: sha256
+```
+
 # License
 
 The scripts and documentation in this project are released under the [MIT License](LICENSE)

__test__/git-auth-helper.test.ts

@@ -824,7 +824,8 @@ async function setup(testName: string): Promise<void> {
     sshUser: '',
     workflowOrganizationId: 123456,
     setSafeDirectory: true,
-    githubServerUrl: githubServerUrl
+    githubServerUrl: githubServerUrl,
+    objectFormat: undefined
   }
 }
 

__test__/git-command-manager.test.ts

@@ -375,4 +375,31 @@ describe('Test fetchDepth and fetchTags options', () => {
       expect.any(Object)
     )
   })
+
+  it('should call execGit wiwth the correct arguments when sha256 is used', async () => {
+    jest.spyOn(exec, 'exec').mockImplementation(mockExec)
+
+    const workingDirectory = 'test'
+    const lfs = false
+    const doSparseCheckout = false
+    git = await commandManager.createCommandManager(
+      workingDirectory,
+      lfs,
+      doSparseCheckout
+    )
+
+    await git.init({objectFormat: 'sha256'})
+    // await git.init({objectFormat: undefined})
+
+    expect(mockExec).toHaveBeenCalledWith(
+      expect.any(String),
+      [
+        'init',
+        '--object-format=sha256',
+        'test'
+      ],
+      expect.any(Object)
+    )
+  })
 })
+