Fix includeIf case sensitivity on Windows self-hosted runners

Switch to includeIf.gitdir/i: on Windows so path matching is
case-insensitive, matching the filesystem behavior. This fixes
auth failures on self-hosted Windows runners where the workspace
folder casing doesn't match between the runner config and disk.

Also update the cleanup regex to handle both gitdir: and gitdir/i:
variants.

Fixes #2345

__test__/git-auth-helper.test.ts

@@ -974,6 +974,46 @@ describe('git-auth-helper tests', () => {
     ).toBe(false)
     expect((authHelper as any).testCredentialsConfigPath('')).toBe(false)
   })
+
+  const includeIfCleanupRegex_matchesBothVariants =
+    'includeIf cleanup regex matches both gitdir: and gitdir/i: keys'
+  it(includeIfCleanupRegex_matchesBothVariants, async () => {
+    // The cleanup regex must match both variants so credential
+    // removal works regardless of which was written
+    const regex = /^includeIf\.gitdir(\/i)?:/
+    expect(regex.test('includeIf.gitdir:D:/workspaces/repo/.git.path')).toBe(
+      true
+    )
+    expect(regex.test('includeIf.gitdir/i:D:/Workspaces/repo/.git.path')).toBe(
+      true
+    )
+    expect(regex.test('includeIf.gitdir/i:/github/workspace/.git.path')).toBe(
+      true
+    )
+    expect(regex.test('includeIf.gitdir:~/projects/foo/.git.path')).toBe(true)
+    expect(regex.test('includeIf.onbranch:main.path')).toBe(false)
+    expect(regex.test('include.path')).toBe(false)
+  })
+
+  const includeIfDirective_usesCorrectVariantForPlatform =
+    'includeIf directive uses gitdir/i on Windows and gitdir on other platforms'
+  it(includeIfDirective_usesCorrectVariantForPlatform, async () => {
+    await setup(includeIfDirective_usesCorrectVariantForPlatform)
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+    await authHelper.configureAuth()
+
+    const localConfigContent = (
+      await fs.promises.readFile(localGitConfigPath)
+    ).toString()
+
+    if (isWindows) {
+      expect(localConfigContent).toContain('includeIf.gitdir/i:')
+      expect(localConfigContent).not.toContain('includeIf.gitdir:')
+    } else {
+      expect(localConfigContent).toContain('includeIf.gitdir:')
+      expect(localConfigContent).not.toContain('includeIf.gitdir/i:')
+    }
+  })
 })
 
 async function setup(testName: string): Promise<void> {
@@ -1103,7 +1143,6 @@ async function setup(testName: string): Promise<void> {
     ),
     tryDisableAutomaticGarbageCollection: jest.fn(),
     tryGetFetchUrl: jest.fn(),
-    tryGetObjectFormat: jest.fn(async () => ({format: '', succeeded: true})),
     tryGetConfigValues: jest.fn(
       async (
         key: string,

__test__/git-command-manager.test.ts

@@ -378,169 +378,6 @@ describe('Test fetchDepth and fetchTags options', () => {
   })
 })
 
-describe('repository object format', () => {
-  beforeEach(async () => {
-    jest.spyOn(fshelper, 'fileExistsSync').mockImplementation(jest.fn())
-    jest.spyOn(fshelper, 'directoryExistsSync').mockImplementation(jest.fn())
-  })
-
-  afterEach(() => {
-    jest.restoreAllMocks()
-  })
-
-  it('detects SHA-256 from a 64-character HEAD oid', async () => {
-    mockExec.mockImplementation((path, args, options) => {
-      if (args.includes('version')) {
-        options.listeners.stdout(Buffer.from('git version 2.50.1'))
-      }
-
-      if (args.includes('ls-remote')) {
-        options.listeners.stdout(
-          Buffer.from(
-            'ref: refs/heads/main\tHEAD\n' +
-              '9422233ca7ee1b17f1e905d0e141faf0c401556c41cdc6acd71c6bd685da2e92\tHEAD\n'
-          )
-        )
-      }
-
-      return 0
-    })
-    jest.spyOn(exec, 'exec').mockImplementation(mockExec)
-
-    git = await commandManager.createCommandManager('test', false, false)
-
-    const objectFormat = await git.tryGetObjectFormat(
-      'https://github.com/example/repo'
-    )
-
-    expect(objectFormat).toEqual({format: 'sha256', succeeded: true})
-    expect(mockExec).toHaveBeenCalledWith(
-      expect.any(String),
-      [
-        '-c',
-        'protocol.version=2',
-        'ls-remote',
-        '--quiet',
-        '--exit-code',
-        '--symref',
-        'https://github.com/example/repo',
-        'HEAD'
-      ],
-      expect.objectContaining({
-        ignoreReturnCode: true,
-        silent: true
-      })
-    )
-  })
-
-  it('detects SHA-1 from a 40-character HEAD oid', async () => {
-    mockExec.mockImplementation((path, args, options) => {
-      if (args.includes('version')) {
-        options.listeners.stdout(Buffer.from('git version 2.50.1'))
-      }
-
-      if (args.includes('ls-remote')) {
-        options.listeners.stdout(
-          Buffer.from(
-            'ref: refs/heads/main\tHEAD\n' +
-              'c988866043f035e6a46509872215f91d879044c9\tHEAD\n'
-          )
-        )
-      }
-
-      return 0
-    })
-    jest.spyOn(exec, 'exec').mockImplementation(mockExec)
-
-    git = await commandManager.createCommandManager('test', false, false)
-
-    await expect(
-      git.tryGetObjectFormat('https://github.com/example/repo')
-    ).resolves.toEqual({format: 'sha1', succeeded: true})
-  })
-
-  it('returns unsuccessful when HEAD does not resolve to a recognized object id', async () => {
-    mockExec.mockImplementation((path, args, options) => {
-      if (args.includes('version')) {
-        options.listeners.stdout(Buffer.from('git version 2.50.1'))
-      }
-
-      if (args.includes('ls-remote')) {
-        options.listeners.stdout(Buffer.from('ref: refs/heads/main\tHEAD\n'))
-      }
-
-      return 0
-    })
-    jest.spyOn(exec, 'exec').mockImplementation(mockExec)
-
-    git = await commandManager.createCommandManager('test', false, false)
-
-    await expect(
-      git.tryGetObjectFormat('https://github.com/example/repo')
-    ).resolves.toEqual({format: '', succeeded: false})
-  })
-
-  it('returns unsuccessful when object format detection cannot reach the remote', async () => {
-    mockExec.mockImplementation((path, args, options) => {
-      if (args.includes('version')) {
-        options.listeners.stdout(Buffer.from('git version 2.50.1'))
-        return 0
-      }
-
-      return 128
-    })
-    jest.spyOn(exec, 'exec').mockImplementation(mockExec)
-
-    git = await commandManager.createCommandManager('test', false, false)
-
-    await expect(
-      git.tryGetObjectFormat('https://github.com/example/repo')
-    ).resolves.toEqual({format: '', succeeded: false})
-  })
-
-  it('initializes SHA-256 repositories with the matching object format', async () => {
-    mockExec.mockImplementation((path, args, options) => {
-      if (args.includes('version')) {
-        options.listeners.stdout(Buffer.from('git version 2.50.1'))
-      }
-
-      return 0
-    })
-    jest.spyOn(exec, 'exec').mockImplementation(mockExec)
-
-    git = await commandManager.createCommandManager('test', false, false)
-
-    await git.init('sha256')
-
-    expect(mockExec).toHaveBeenCalledWith(
-      expect.any(String),
-      ['init', '--object-format=sha256', 'test'],
-      expect.any(Object)
-    )
-  })
-
-  it('initializes SHA-1 repositories with existing default arguments', async () => {
-    mockExec.mockImplementation((path, args, options) => {
-      if (args.includes('version')) {
-        options.listeners.stdout(Buffer.from('git version 2.50.1'))
-      }
-
-      return 0
-    })
-    jest.spyOn(exec, 'exec').mockImplementation(mockExec)
-
-    git = await commandManager.createCommandManager('test', false, false)
-
-    await git.init('sha1')
-
-    expect(mockExec).toHaveBeenCalledWith(
-      expect.any(String),
-      ['init', 'test'],
-      expect.any(Object)
-    )
-  })
-})
-
 describe('git user-agent with orchestration ID', () => {
   beforeEach(async () => {
     jest.spyOn(fshelper, 'fileExistsSync').mockImplementation(jest.fn())

__test__/git-directory-helper.test.ts

@@ -501,7 +501,6 @@ async function setup(testName: string): Promise<void> {
       await fs.promises.stat(path.join(repositoryPath, '.git'))
       return repositoryUrl
     }),
-    tryGetObjectFormat: jest.fn(async () => ({format: '', succeeded: true})),
     tryGetConfigValues: jest.fn(),
     tryGetConfigKeys: jest.fn(),
     tryReset: jest.fn(async () => {

__test__/github-api-helper.test.ts

@@ -1,164 +0,0 @@
-import * as core from '@actions/core'
-import * as github from '@actions/github'
-import * as githubApiHelper from '../lib/github-api-helper'
-
-describe('github-api-helper object format', () => {
-  let getOctokitSpy: jest.SpyInstance
-  let debugSpy: jest.SpyInstance
-  let repoGet: jest.Mock
-  let branchGet: jest.Mock
-
-  function mockObjectFormatApi(defaultBranch: string, commitSha: string): void {
-    repoGet = jest.fn(async () => ({
-      data: {
-        default_branch: defaultBranch
-      }
-    }))
-    branchGet = jest.fn(async () => ({
-      data: {
-        commit: {
-          sha: commitSha
-        }
-      }
-    }))
-    getOctokitSpy = jest.spyOn(github, 'getOctokit').mockReturnValue({
-      rest: {
-        repos: {
-          get: repoGet,
-          getBranch: branchGet
-        }
-      }
-    } as any)
-  }
-
-  beforeEach(() => {
-    debugSpy = jest.spyOn(core, 'debug').mockImplementation(jest.fn())
-  })
-
-  afterEach(() => {
-    jest.restoreAllMocks()
-  })
-
-  it('detects SHA-256 from the default branch commit SHA', async () => {
-    const commitSha =
-      '9422233ca7ee1b17f1e905d0e141faf0c401556c41cdc6acd71c6bd685da2e92'
-    mockObjectFormatApi('main', commitSha)
-
-    await expect(
-      githubApiHelper.tryGetRepositoryObjectFormat('token', 'owner', 'repo')
-    ).resolves.toEqual({
-      defaultBranch: 'main',
-      format: 'sha256',
-      succeeded: true
-    })
-
-    expect(getOctokitSpy).toHaveBeenCalledWith(
-      'token',
-      expect.objectContaining({baseUrl: 'https://api.github.com'})
-    )
-    expect(repoGet).toHaveBeenCalledWith({owner: 'owner', repo: 'repo'})
-    expect(branchGet).toHaveBeenCalledWith({
-      owner: 'owner',
-      repo: 'repo',
-      branch: 'main'
-    })
-  })
-
-  it('detects SHA-1 from the default branch commit SHA', async () => {
-    mockObjectFormatApi('main', 'c988866043f035e6a46509872215f91d879044c9')
-
-    await expect(
-      githubApiHelper.tryGetRepositoryObjectFormat('token', 'owner', 'repo')
-    ).resolves.toEqual({defaultBranch: 'main', format: 'sha1', succeeded: true})
-  })
-
-  it('detects object format from an existing commit without API calls', async () => {
-    const commitSha =
-      '9422233ca7ee1b17f1e905d0e141faf0c401556c41cdc6acd71c6bd685da2e92'
-    getOctokitSpy = jest.spyOn(github, 'getOctokit')
-
-    await expect(
-      githubApiHelper.tryGetRepositoryObjectFormat(
-        'token',
-        'owner',
-        'repo',
-        undefined,
-        undefined,
-        commitSha
-      )
-    ).resolves.toEqual({format: 'sha256', succeeded: true})
-
-    expect(getOctokitSpy).not.toHaveBeenCalled()
-  })
-
-  it('uses a branch ref directly without looking up the default branch', async () => {
-    const commitSha = 'c988866043f035e6a46509872215f91d879044c9'
-    repoGet = jest.fn()
-    branchGet = jest.fn(async () => ({
-      data: {
-        commit: {
-          sha: commitSha
-        }
-      }
-    }))
-    getOctokitSpy = jest.spyOn(github, 'getOctokit').mockReturnValue({
-      rest: {
-        repos: {
-          get: repoGet,
-          getBranch: branchGet
-        }
-      }
-    } as any)
-
-    await expect(
-      githubApiHelper.tryGetRepositoryObjectFormat(
-        'token',
-        'owner',
-        'repo',
-        undefined,
-        'refs/heads/feature'
-      )
-    ).resolves.toEqual({format: 'sha1', succeeded: true})
-
-    expect(repoGet).not.toHaveBeenCalled()
-    expect(branchGet).toHaveBeenCalledWith({
-      owner: 'owner',
-      repo: 'repo',
-      branch: 'feature'
-    })
-  })
-
-  it('returns unsuccessful when the default branch commit SHA is not recognized', async () => {
-    mockObjectFormatApi('main', 'not-a-sha')
-
-    await expect(
-      githubApiHelper.tryGetRepositoryObjectFormat('token', 'owner', 'repo')
-    ).resolves.toEqual({format: '', succeeded: false})
-    expect(debugSpy).toHaveBeenCalledWith(
-      'Unable to determine repository object format from commit SHA'
-    )
-  })
-
-  it('returns unsuccessful when the repository API lookup fails', async () => {
-    repoGet = jest.fn(async () => {
-      throw new Error('not found')
-    })
-    branchGet = jest.fn()
-    jest.spyOn(github, 'getOctokit').mockReturnValue({
-      rest: {
-        repos: {
-          get: repoGet,
-          getBranch: branchGet
-        }
-      }
-    } as any)
-
-    await expect(
-      githubApiHelper.tryGetRepositoryObjectFormat('token', 'owner', 'repo')
-    ).resolves.toEqual({format: '', succeeded: false})
-    expect(branchGet).not.toHaveBeenCalled()
-    expect(debugSpy).toHaveBeenCalledWith(
-      'Unable to determine repository object format: not found'
-    )
-  })
-})

dist/index.js

@@ -151,6 +151,12 @@ const stateHelper = __importStar(__nccwpck_require__(4866));
 const urlHelper = __importStar(__nccwpck_require__(9437));
 const uuid_1 = __nccwpck_require__(5840);
 const IS_WINDOWS = process.platform === 'win32';
+// Use case-insensitive gitdir matching on Windows to handle path casing mismatches
+// between the runner's GITHUB_WORKSPACE and the actual filesystem casing.
+// See: https://github.com/actions/checkout/issues/2345
+const INCLUDE_IF_GITDIR = IS_WINDOWS
+    ? 'includeIf.gitdir/i:'
+    : 'includeIf.gitdir:';
 const SSH_COMMAND_KEY = 'core.sshCommand';
 function createAuthHelper(git, settings) {
     return new GitAuthHelper(git, settings);
@@ -270,7 +276,7 @@ class GitAuthHelper {
                     let submoduleGitDir = path.dirname(configPath); // The config file is at .git/modules/submodule-name/config
                     submoduleGitDir = submoduleGitDir.replace(/\\/g, '/'); // Use forward slashes, even on Windows
                     // Configure host includeIf
-                    yield this.git.config(`includeIf.gitdir:${submoduleGitDir}.path`, credentialsConfigPath, false, // globalConfig?
+                    yield this.git.config(`${INCLUDE_IF_GITDIR}${submoduleGitDir}.path`, credentialsConfigPath, false, // globalConfig?
                     false, // add?
                     configPath);
                     // Container submodule git directory
@@ -280,7 +286,7 @@ class GitAuthHelper {
                     relativeSubmoduleGitDir = relativeSubmoduleGitDir.replace(/\\/g, '/'); // Use forward slashes, even on Windows
                     const containerSubmoduleGitDir = path.posix.join('/github/workspace', relativeSubmoduleGitDir);
                     // Configure container includeIf
-                    yield this.git.config(`includeIf.gitdir:${containerSubmoduleGitDir}.path`, containerCredentialsPath, false, // globalConfig?
+                    yield this.git.config(`${INCLUDE_IF_GITDIR}${containerSubmoduleGitDir}.path`, containerCredentialsPath, false, // globalConfig?
                     false, // add?
                     configPath);
                 }
@@ -410,10 +416,10 @@ class GitAuthHelper {
                 let gitDir = path.join(this.git.getWorkingDirectory(), '.git');
                 gitDir = gitDir.replace(/\\/g, '/'); // Use forward slashes, even on Windows
                 // Configure host includeIf
-                const hostIncludeKey = `includeIf.gitdir:${gitDir}.path`;
+                const hostIncludeKey = `${INCLUDE_IF_GITDIR}${gitDir}.path`;
                 yield this.git.config(hostIncludeKey, credentialsConfigPath);
                 // Configure host includeIf for worktrees
-                const hostWorktreeIncludeKey = `includeIf.gitdir:${gitDir}/worktrees/*.path`;
+                const hostWorktreeIncludeKey = `${INCLUDE_IF_GITDIR}${gitDir}/worktrees/*.path`;
                 yield this.git.config(hostWorktreeIncludeKey, credentialsConfigPath);
                 // Container git directory
                 const workingDirectory = this.git.getWorkingDirectory();
@@ -425,10 +431,10 @@ class GitAuthHelper {
                 // Container credentials config path
                 const containerCredentialsPath = path.posix.join('/github/runner_temp', path.basename(credentialsConfigPath));
                 // Configure container includeIf
-                const containerIncludeKey = `includeIf.gitdir:${containerGitDir}.path`;
+                const containerIncludeKey = `${INCLUDE_IF_GITDIR}${containerGitDir}.path`;
                 yield this.git.config(containerIncludeKey, containerCredentialsPath);
                 // Configure container includeIf for worktrees
-                const containerWorktreeIncludeKey = `includeIf.gitdir:${containerGitDir}/worktrees/*.path`;
+                const containerWorktreeIncludeKey = `${INCLUDE_IF_GITDIR}${containerGitDir}/worktrees/*.path`;
                 yield this.git.config(containerWorktreeIncludeKey, containerCredentialsPath);
             }
         });
@@ -565,7 +571,7 @@ class GitAuthHelper {
             const credentialsPaths = new Set();
             try {
                 // Get all includeIf.gitdir keys
-                const keys = yield this.git.tryGetConfigKeys('^includeIf\\.gitdir:', false, // globalConfig?
+                const keys = yield this.git.tryGetConfigKeys('^includeIf\\.gitdir(/i)?:', false, // globalConfig?
                 configPath);
                 for (const key of keys) {
                     // Get all values for this key
@@ -896,14 +902,9 @@ class GitCommandManager {
     getWorkingDirectory() {
         return this.workingDirectory;
     }
-    init(objectFormat) {
+    init() {
         return __awaiter(this, void 0, void 0, function* () {
-            const args = ['init'];
+            yield this.execGit(['init', this.workingDirectory]);
-            if (objectFormat === 'sha256') {
-                args.push('--object-format=sha256');
-            }
-            args.push(this.workingDirectory);
-            yield this.execGit(args);
         });
     }
     isDetached() {
@@ -1061,45 +1062,6 @@ class GitCommandManager {
             return stdout;
         });
     }
-    tryGetObjectFormat(repositoryUrl) {
-        return __awaiter(this, void 0, void 0, function* () {
-            var _a;
-            try {
-                const output = yield this.execGit([
-                    '-c',
-                    'protocol.version=2',
-                    'ls-remote',
-                    '--quiet',
-                    '--exit-code',
-                    '--symref',
-                    repositoryUrl,
-                    'HEAD'
-                ], true, true);
-                if (output.exitCode !== 0) {
-                    core.debug(`Unable to determine repository object format: git ls-remote exited with ${output.exitCode}`);
-                    return { format: '', succeeded: false };
-                }
-                for (const line of output.stdout.trim().split('\n')) {
-                    const [oid, ref] = line.split('\t');
-                    if (ref !== 'HEAD') {
-                        continue;
-                    }
-                    if (/^[0-9a-fA-F]{64}$/.test(oid)) {
-                        return { format: 'sha256', succeeded: true };
-                    }
-                    if (/^[0-9a-fA-F]{40}$/.test(oid)) {
-                        return { format: 'sha1', succeeded: true };
-                    }
-                }
-                core.debug('Unable to determine repository object format from HEAD');
-                return { format: '', succeeded: false };
-            }
-            catch (err) {
-                core.debug(`Unable to determine repository object format: ${(_a = err === null || err === void 0 ? void 0 : err.message) !== null && _a !== void 0 ? _a : err}`);
-                return { format: '', succeeded: false };
-            }
-        });
-    }
     tryGetConfigValues(configKey, globalConfig, configFile) {
         return __awaiter(this, void 0, void 0, function* () {
             const args = ['config'];
@@ -1528,24 +1490,10 @@ function getSource(settings) {
             }
             // Save state for POST action
             stateHelper.setRepositoryPath(settings.repositoryPath);
-            let defaultBranch = '';
             // Initialize the repository
             if (!fsHelper.directoryExistsSync(path.join(settings.repositoryPath, '.git'))) {
-                core.startGroup('Determining repository object format');
-                let objectFormatResult = yield githubApiHelper.tryGetRepositoryObjectFormat(settings.authToken, settings.repositoryOwner, settings.repositoryName, settings.githubServerUrl, settings.ref, settings.commit);
-                if (!objectFormatResult.succeeded) {
-                    objectFormatResult = yield git.tryGetObjectFormat(repositoryUrl);
-                }
-                const objectFormat = objectFormatResult.succeeded
-                    ? objectFormatResult.format
-                    : '';
-                defaultBranch = objectFormatResult.defaultBranch || '';
-                if (objectFormat === 'sha256') {
-                    core.info('Detected SHA-256 repository object format');
-                }
-                core.endGroup();
                 core.startGroup('Initializing the repository');
-                yield git.init(objectFormat);
+                yield git.init();
                 yield git.remoteAdd('origin', repositoryUrl);
                 core.endGroup();
             }
@@ -1569,10 +1517,6 @@ function getSource(settings) {
                 if (settings.sshKey) {
                     settings.ref = yield git.getDefaultBranch(repositoryUrl);
                 }
-                else if (defaultBranch) {
-                    core.info(`Default branch '${defaultBranch}'`);
-                    settings.ref = `refs/heads/${defaultBranch}`;
-                }
                 else {
                     settings.ref = yield githubApiHelper.getDefaultBranch(settings.authToken, settings.repositoryOwner, settings.repositoryName, settings.githubServerUrl);
                 }
@@ -1872,7 +1816,6 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
 Object.defineProperty(exports, "__esModule", ({ value: true }));
 exports.downloadRepository = downloadRepository;
 exports.getDefaultBranch = getDefaultBranch;
-exports.tryGetRepositoryObjectFormat = tryGetRepositoryObjectFormat;
 const assert = __importStar(__nccwpck_require__(9491));
 const core = __importStar(__nccwpck_require__(2186));
 const fs = __importStar(__nccwpck_require__(7147));
@@ -1974,69 +1917,6 @@ function getDefaultBranch(authToken, owner, repo, baseUrl) {
         }));
     });
 }
-function tryGetRepositoryObjectFormat(authToken, owner, repo, baseUrl, ref, commit) {
-    return __awaiter(this, void 0, void 0, function* () {
-        var _a;
-        try {
-            const commitFormat = getObjectFormat(commit);
-            if (commitFormat) {
-                return { format: commitFormat, succeeded: true };
-            }
-            const octokit = github.getOctokit(authToken, {
-                baseUrl: (0, url_helper_1.getServerApiUrl)(baseUrl)
-            });
-            let branchName = getBranchName(ref);
-            let defaultBranch = '';
-            if (!branchName) {
-                const repository = yield octokit.rest.repos.get({ owner, repo });
-                defaultBranch = repository.data.default_branch;
-                assert.ok(defaultBranch, 'default_branch cannot be empty');
-                branchName = defaultBranch;
-            }
-            const branch = yield octokit.rest.repos.getBranch({
-                owner,
-                repo,
-                branch: branchName
-            });
-            const branchFormat = getObjectFormat(branch.data.commit.sha);
-            if (branchFormat) {
-                return {
-                    defaultBranch: defaultBranch || undefined,
-                    format: branchFormat,
-                    succeeded: true
-                };
-            }
-            core.debug('Unable to determine repository object format from commit SHA');
-            return { format: '', succeeded: false };
-        }
-        catch (err) {
-            core.debug(`Unable to determine repository object format: ${(_a = err === null || err === void 0 ? void 0 : err.message) !== null && _a !== void 0 ? _a : err}`);
-            return { format: '', succeeded: false };
-        }
-    });
-}
-function getBranchName(ref) {
-    if (!ref) {
-        return '';
-    }
-    const headsPrefix = 'refs/heads/';
-    if (ref.startsWith(headsPrefix)) {
-        return ref.substring(headsPrefix.length);
-    }
-    if (!ref.startsWith('refs/') && !getObjectFormat(ref)) {
-        return ref;
-    }
-    return '';
-}
-function getObjectFormat(sha) {
-    if (/^[0-9a-fA-F]{64}$/.test(sha || '')) {
-        return 'sha256';
-    }
-    if (/^[0-9a-fA-F]{40}$/.test(sha || '')) {
-        return 'sha1';
-    }
-    return '';
-}
 function downloadArchive(authToken, owner, repo, ref, commit, baseUrl) {
     return __awaiter(this, void 0, void 0, function* () {
         const octokit = github.getOctokit(authToken, {

src/git-auth-helper.ts

@@ -13,6 +13,12 @@ import {IGitCommandManager} from './git-command-manager'
 import {IGitSourceSettings} from './git-source-settings'
 
 const IS_WINDOWS = process.platform === 'win32'
+// Use case-insensitive gitdir matching on Windows to handle path casing mismatches
+// between the runner's GITHUB_WORKSPACE and the actual filesystem casing.
+// See: https://github.com/actions/checkout/issues/2345
+const INCLUDE_IF_GITDIR = IS_WINDOWS
+  ? 'includeIf.gitdir/i:'
+  : 'includeIf.gitdir:'
 const SSH_COMMAND_KEY = 'core.sshCommand'
 
 export interface IGitAuthHelper {
@@ -182,7 +188,7 @@ class GitAuthHelper {
 
         // Configure host includeIf
         await this.git.config(
-          `includeIf.gitdir:${submoduleGitDir}.path`,
+          `${INCLUDE_IF_GITDIR}${submoduleGitDir}.path`,
           credentialsConfigPath,
           false, // globalConfig?
           false, // add?
@@ -204,7 +210,7 @@ class GitAuthHelper {
 
         // Configure container includeIf
         await this.git.config(
-          `includeIf.gitdir:${containerSubmoduleGitDir}.path`,
+          `${INCLUDE_IF_GITDIR}${containerSubmoduleGitDir}.path`,
           containerCredentialsPath,
           false, // globalConfig?
           false, // add?
@@ -371,11 +377,11 @@ class GitAuthHelper {
       gitDir = gitDir.replace(/\\/g, '/') // Use forward slashes, even on Windows
 
       // Configure host includeIf
-      const hostIncludeKey = `includeIf.gitdir:${gitDir}.path`
+      const hostIncludeKey = `${INCLUDE_IF_GITDIR}${gitDir}.path`
       await this.git.config(hostIncludeKey, credentialsConfigPath)
 
       // Configure host includeIf for worktrees
-      const hostWorktreeIncludeKey = `includeIf.gitdir:${gitDir}/worktrees/*.path`
+      const hostWorktreeIncludeKey = `${INCLUDE_IF_GITDIR}${gitDir}/worktrees/*.path`
       await this.git.config(hostWorktreeIncludeKey, credentialsConfigPath)
 
       // Container git directory
@@ -397,11 +403,11 @@ class GitAuthHelper {
       )
 
       // Configure container includeIf
-      const containerIncludeKey = `includeIf.gitdir:${containerGitDir}.path`
+      const containerIncludeKey = `${INCLUDE_IF_GITDIR}${containerGitDir}.path`
       await this.git.config(containerIncludeKey, containerCredentialsPath)
 
       // Configure container includeIf for worktrees
-      const containerWorktreeIncludeKey = `includeIf.gitdir:${containerGitDir}/worktrees/*.path`
+      const containerWorktreeIncludeKey = `${INCLUDE_IF_GITDIR}${containerGitDir}/worktrees/*.path`
       await this.git.config(
         containerWorktreeIncludeKey,
         containerCredentialsPath
@@ -554,7 +560,7 @@ class GitAuthHelper {
     try {
       // Get all includeIf.gitdir keys
       const keys = await this.git.tryGetConfigKeys(
-        '^includeIf\\.gitdir:',
+        '^includeIf\\.gitdir(/i)?:',
         false, // globalConfig?
         configPath
       )

src/git-command-manager.ts

@@ -15,11 +15,6 @@ import {GitVersion} from './git-version'
 export const MinimumGitVersion = new GitVersion('2.18')
 export const MinimumGitSparseCheckoutVersion = new GitVersion('2.28')
 
-export interface GitObjectFormatResult {
-  format: string
-  succeeded: boolean
-}
-
 export interface IGitCommandManager {
   branchDelete(remote: boolean, branch: string): Promise<void>
   branchExists(remote: boolean, pattern: string): Promise<boolean>
@@ -48,7 +43,7 @@ export interface IGitCommandManager {
   getDefaultBranch(repositoryUrl: string): Promise<string>
   getSubmoduleConfigPaths(recursive: boolean): Promise<string[]>
   getWorkingDirectory(): string
-  init(objectFormat?: string): Promise<void>
+  init(): Promise<void>
   isDetached(): Promise<boolean>
   lfsFetch(ref: string): Promise<void>
   lfsInstall(): Promise<void>
@@ -73,7 +68,6 @@ export interface IGitCommandManager {
   ): Promise<boolean>
   tryDisableAutomaticGarbageCollection(): Promise<boolean>
   tryGetFetchUrl(): Promise<string>
-  tryGetObjectFormat(repositoryUrl: string): Promise<GitObjectFormatResult>
   tryGetConfigValues(
     configKey: string,
     globalConfig?: boolean,
@@ -370,14 +364,8 @@ class GitCommandManager {
     return this.workingDirectory
   }
 
-  async init(objectFormat?: string): Promise<void> {
+  async init(): Promise<void> {
-    const args = ['init']
+    await this.execGit(['init', this.workingDirectory])
-    if (objectFormat === 'sha256') {
-      args.push('--object-format=sha256')
-    }
-    args.push(this.workingDirectory)
-
-    await this.execGit(args)
   }
 
   async isDetached(): Promise<boolean> {
@@ -548,55 +536,6 @@ class GitCommandManager {
     return stdout
   }
 
-  async tryGetObjectFormat(
-    repositoryUrl: string
-  ): Promise<GitObjectFormatResult> {
-    try {
-      const output = await this.execGit(
-        [
-          '-c',
-          'protocol.version=2',
-          'ls-remote',
-          '--quiet',
-          '--exit-code',
-          '--symref',
-          repositoryUrl,
-          'HEAD'
-        ],
-        true,
-        true
-      )
-
-      if (output.exitCode !== 0) {
-        core.debug(
-          `Unable to determine repository object format: git ls-remote exited with ${output.exitCode}`
-        )
-        return {format: '', succeeded: false}
-      }
-
-      for (const line of output.stdout.trim().split('\n')) {
-        const [oid, ref] = line.split('\t')
-        if (ref !== 'HEAD') {
-          continue
-        }
-        if (/^[0-9a-fA-F]{64}$/.test(oid)) {
-          return {format: 'sha256', succeeded: true}
-        }
-        if (/^[0-9a-fA-F]{40}$/.test(oid)) {
-          return {format: 'sha1', succeeded: true}
-        }
-      }
-
-      core.debug('Unable to determine repository object format from HEAD')
-      return {format: '', succeeded: false}
-    } catch (err) {
-      core.debug(
-        `Unable to determine repository object format: ${(err as any)?.message ?? err}`
-      )
-      return {format: '', succeeded: false}
-    }
-  }
-
   async tryGetConfigValues(
     configKey: string,
     globalConfig?: boolean,

src/git-source-provider.ts

@@ -105,36 +105,12 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
     // Save state for POST action
     stateHelper.setRepositoryPath(settings.repositoryPath)
 
-    let defaultBranch = ''
-
     // Initialize the repository
     if (
       !fsHelper.directoryExistsSync(path.join(settings.repositoryPath, '.git'))
     ) {
-      core.startGroup('Determining repository object format')
-      let objectFormatResult =
-        await githubApiHelper.tryGetRepositoryObjectFormat(
-          settings.authToken,
-          settings.repositoryOwner,
-          settings.repositoryName,
-          settings.githubServerUrl,
-          settings.ref,
-          settings.commit
-        )
-      if (!objectFormatResult.succeeded) {
-        objectFormatResult = await git.tryGetObjectFormat(repositoryUrl)
-      }
-      const objectFormat = objectFormatResult.succeeded
-        ? objectFormatResult.format
-        : ''
-      defaultBranch = objectFormatResult.defaultBranch || ''
-      if (objectFormat === 'sha256') {
-        core.info('Detected SHA-256 repository object format')
-      }
-      core.endGroup()
-
       core.startGroup('Initializing the repository')
-      await git.init(objectFormat)
+      await git.init()
       await git.remoteAdd('origin', repositoryUrl)
       core.endGroup()
     }
@@ -162,9 +138,6 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
       core.startGroup('Determining the default branch')
       if (settings.sshKey) {
         settings.ref = await git.getDefaultBranch(repositoryUrl)
-      } else if (defaultBranch) {
-        core.info(`Default branch '${defaultBranch}'`)
-        settings.ref = `refs/heads/${defaultBranch}`
       } else {
         settings.ref = await githubApiHelper.getDefaultBranch(
           settings.authToken,

src/github-api-helper.ts

@@ -11,12 +11,6 @@ import {getServerApiUrl} from './url-helper'
 
 const IS_WINDOWS = process.platform === 'win32'
 
-export interface RepositoryObjectFormatResult {
-  defaultBranch?: string
-  format: string
-  succeeded: boolean
-}
-
 export async function downloadRepository(
   authToken: string,
   owner: string,
@@ -128,84 +122,6 @@ export async function getDefaultBranch(
   })
 }
 
-export async function tryGetRepositoryObjectFormat(
-  authToken: string,
-  owner: string,
-  repo: string,
-  baseUrl?: string,
-  ref?: string,
-  commit?: string
-): Promise<RepositoryObjectFormatResult> {
-  try {
-    const commitFormat = getObjectFormat(commit)
-    if (commitFormat) {
-      return {format: commitFormat, succeeded: true}
-    }
-
-    const octokit = github.getOctokit(authToken, {
-      baseUrl: getServerApiUrl(baseUrl)
-    })
-
-    let branchName = getBranchName(ref)
-    let defaultBranch = ''
-    if (!branchName) {
-      const repository = await octokit.rest.repos.get({owner, repo})
-      defaultBranch = repository.data.default_branch
-      assert.ok(defaultBranch, 'default_branch cannot be empty')
-      branchName = defaultBranch
-    }
-
-    const branch = await octokit.rest.repos.getBranch({
-      owner,
-      repo,
-      branch: branchName
-    })
-    const branchFormat = getObjectFormat(branch.data.commit.sha)
-    if (branchFormat) {
-      return {
-        defaultBranch: defaultBranch || undefined,
-        format: branchFormat,
-        succeeded: true
-      }
-    }
-
-    core.debug('Unable to determine repository object format from commit SHA')
-    return {format: '', succeeded: false}
-  } catch (err) {
-    core.debug(
-      `Unable to determine repository object format: ${(err as any)?.message ?? err}`
-    )
-    return {format: '', succeeded: false}
-  }
-}
-
-function getBranchName(ref?: string): string {
-  if (!ref) {
-    return ''
-  }
-
-  const headsPrefix = 'refs/heads/'
-  if (ref.startsWith(headsPrefix)) {
-    return ref.substring(headsPrefix.length)
-  }
-
-  if (!ref.startsWith('refs/') && !getObjectFormat(ref)) {
-    return ref
-  }
-
-  return ''
-}
-
-function getObjectFormat(sha?: string): string {
-  if (/^[0-9a-fA-F]{64}$/.test(sha || '')) {
-    return 'sha256'
-  }
-  if (/^[0-9a-fA-F]{40}$/.test(sha || '')) {
-    return 'sha1'
-  }
-  return ''
-}
-
 async function downloadArchive(
   authToken: string,
   owner: string,