Log Git initialization failures before REST fallback

__test__/git-source-provider.test.ts

@@ -0,0 +1,102 @@
+import {jest, describe, it, expect, beforeEach} from '@jest/globals'
+
+const mockInfo = jest.fn()
+const mockCreateCommandManager = jest.fn<() => Promise<unknown>>()
+const mockPrepareExistingDirectory = jest.fn()
+const mockDownloadRepository = jest.fn()
+const mockGetState = jest.fn(() => '')
+
+jest.unstable_mockModule('@actions/core', () => ({
+  info: mockInfo,
+  startGroup: jest.fn(),
+  endGroup: jest.fn(),
+  getState: mockGetState,
+  saveState: jest.fn()
+}))
+
+jest.unstable_mockModule('@actions/io', () => ({
+  mkdirP: jest.fn(),
+  rmRF: jest.fn()
+}))
+
+jest.unstable_mockModule('../src/fs-helper.js', () => ({
+  directoryExistsSync: jest.fn(() => false),
+  fileExistsSync: jest.fn(() => false)
+}))
+
+jest.unstable_mockModule('../src/git-auth-helper.js', () => ({
+  createAuthHelper: jest.fn()
+}))
+
+jest.unstable_mockModule('../src/git-command-manager.js', () => ({
+  createCommandManager: mockCreateCommandManager,
+  MinimumGitVersion: '2.18',
+  MinimumGitSparseCheckoutVersion: '2.28'
+}))
+
+jest.unstable_mockModule('../src/git-directory-helper.js', () => ({
+  prepareExistingDirectory: mockPrepareExistingDirectory
+}))
+
+jest.unstable_mockModule('../src/github-api-helper.js', () => ({
+  downloadRepository: mockDownloadRepository
+}))
+
+jest.unstable_mockModule('../src/url-helper.js', () => ({
+  getFetchUrl: jest.fn(() => 'https://github.com/owner/repo.git'),
+  getServerApiUrl: jest.fn(() => 'https://api.github.com'),
+  getServerUrl: jest.fn(() => new URL('https://github.com')),
+  isGhes: jest.fn(() => false)
+}))
+
+const gitSourceProvider = await import('../src/git-source-provider.js')
+type IGitSourceSettings =
+  import('../src/git-source-settings.js').IGitSourceSettings
+
+describe('git source provider', () => {
+  beforeEach(() => {
+    jest.clearAllMocks()
+    mockCreateCommandManager.mockRejectedValue(
+      new Error(
+        "Minimum Git version required for sparse checkout is 2.28. Your git ('/usr/bin/git') is 2.23"
+      )
+    )
+  })
+
+  it('reports why it falls back to the REST API when Git initialization fails', async () => {
+    const settings: IGitSourceSettings = {
+      repositoryPath: '/tmp/checkout',
+      repositoryOwner: 'owner',
+      repositoryName: 'repo',
+      ref: 'refs/heads/main',
+      commit: '1234567890',
+      clean: true,
+      filter: undefined,
+      sparseCheckout: ['src'],
+      sparseCheckoutConeMode: true,
+      fetchDepth: 1,
+      fetchTags: false,
+      showProgress: true,
+      lfs: false,
+      submodules: false,
+      nestedSubmodules: false,
+      authToken: 'token',
+      sshKey: '',
+      sshKnownHosts: '',
+      sshStrict: true,
+      sshUser: 'git',
+      persistCredentials: true,
+      workflowOrganizationId: undefined,
+      setSafeDirectory: true,
+      githubServerUrl: 'https://github.com',
+      allowUnsafePrCheckout: false
+    }
+
+    await gitSourceProvider.getSource(settings)
+
+    expect(mockInfo).toHaveBeenCalledWith(
+      "Failed to initialize CommandManager: Minimum Git version required for sparse checkout is 2.28. Your git ('/usr/bin/git') is 2.23"
+    )
+    expect(mockDownloadRepository).toHaveBeenCalled()
+  })
+})

dist/index.js

@@ -41957,6 +41957,8 @@ async function getGitCommandManager(settings) {
         return await createCommandManager(settings.repositoryPath, settings.lfs, settings.sparseCheckout != null);
     }
     catch (err) {
+        const errorMessage = err instanceof Error ? err.message : String(err);
+        info(`Failed to initialize CommandManager: ${errorMessage}`);
         // Git is required for LFS
         if (settings.lfs) {
             throw err;

src/git-source-provider.ts

@@ -381,6 +381,9 @@ async function getGitCommandManager(
       settings.sparseCheckout != null
     )
   } catch (err) {
+    const errorMessage = err instanceof Error ? err.message : String(err)
+    core.info(`Failed to initialize CommandManager: ${errorMessage}`)
+
     // Git is required for LFS
     if (settings.lfs) {
       throw err