.

.github/workflows/test.yml

@@ -299,15 +299,18 @@ jobs:
   test-output:
     runs-on: ubuntu-latest
     steps:
-      # Clone this repo
+      # Download the action at the current ref
       - name: Checkout
         uses: actions/checkout@v4.1.6
+        with:
+          path: actions-checkout
 
       # Basic checkout using git
       - name: Checkout basic
         id: checkout
-        uses: ./
+        uses: ./actions-checkout
         with:
+          path: cloned-using-local-action
           ref: test-data/v2/basic
 
       # Verify output
@@ -325,7 +328,3 @@ jobs:
             echo "Expected commit to be 82f71901cf8c021332310dcc8cdba84c4193ff5d"
             exit 1
           fi
-
-      # needed to make checkout post cleanup succeed
-      - name: Fix Checkout
-        uses: actions/checkout@v4.1.6

__test__/git-auth-helper.test.ts

@@ -86,16 +86,29 @@ describe('git-auth-helper tests', () => {
     // Act
     await authHelper.configureAuth()
 
-    // Assert config
+    // Assert config - check that .git/config contains includeIf entries
-    const configContent = (
+    const localConfigContent = (
       await fs.promises.readFile(localGitConfigPath)
     ).toString()
+    expect(
+      localConfigContent.indexOf('includeIf.gitdir:')
+    ).toBeGreaterThanOrEqual(0)
+
+    // Assert credentials config file contains the actual credentials
+    const credentialsFiles = (await fs.promises.readdir(runnerTemp)).filter(
+      f => f.startsWith('git-credentials-') && f.endsWith('.config')
+    )
+    expect(credentialsFiles.length).toBe(1)
+    const credentialsConfigPath = path.join(runnerTemp, credentialsFiles[0])
+    const credentialsContent = (
+      await fs.promises.readFile(credentialsConfigPath)
+    ).toString()
     const basicCredential = Buffer.from(
       `x-access-token:${settings.authToken}`,
       'utf8'
     ).toString('base64')
     expect(
-      configContent.indexOf(
+      credentialsContent.indexOf(
         `http.${expectedServerUrl}/.extraheader AUTHORIZATION: basic ${basicCredential}`
       )
     ).toBeGreaterThanOrEqual(0)
@@ -120,7 +133,7 @@ describe('git-auth-helper tests', () => {
     'inject https://github.com as github server url'
   it(configureAuth_AcceptsGitHubServerUrlSetToGHEC, async () => {
     await testAuthHeader(
-      configureAuth_AcceptsGitHubServerUrl,
+      configureAuth_AcceptsGitHubServerUrlSetToGHEC,
       'https://github.com'
     )
   })
@@ -141,12 +154,17 @@ describe('git-auth-helper tests', () => {
       // Act
       await authHelper.configureAuth()
 
-      // Assert config
+      // Assert config - check credentials config file (not local .git/config)
-      const configContent = (
+      const credentialsFiles = (await fs.promises.readdir(runnerTemp)).filter(
-        await fs.promises.readFile(localGitConfigPath)
+        f => f.startsWith('git-credentials-') && f.endsWith('.config')
+      )
+      expect(credentialsFiles.length).toBe(1)
+      const credentialsConfigPath = path.join(runnerTemp, credentialsFiles[0])
+      const credentialsContent = (
+        await fs.promises.readFile(credentialsConfigPath)
       ).toString()
       expect(
-        configContent.indexOf(
+        credentialsContent.indexOf(
           `http.https://github.com/.extraheader AUTHORIZATION`
         )
       ).toBeGreaterThanOrEqual(0)
@@ -251,13 +269,16 @@ describe('git-auth-helper tests', () => {
       expectedSshCommand
     )
 
-    // Asserty git config
+    // Assert git config
     const gitConfigLines = (await fs.promises.readFile(localGitConfigPath))
       .toString()
       .split('\n')
       .filter(x => x)
-    expect(gitConfigLines).toHaveLength(1)
+    // Should have includeIf entries pointing to credentials file
-    expect(gitConfigLines[0]).toMatch(/^http\./)
+    expect(gitConfigLines.length).toBeGreaterThan(0)
+    expect(
+      gitConfigLines.some(line => line.indexOf('includeIf.gitdir:') >= 0)
+    ).toBeTruthy()
   })
 
   const configureAuth_setsSshCommandWhenPersistCredentialsTrue =
@@ -419,8 +440,20 @@ describe('git-auth-helper tests', () => {
     expect(
       configContent.indexOf('value-from-global-config')
     ).toBeGreaterThanOrEqual(0)
+    // Global config should have include.path pointing to credentials file
+    expect(configContent.indexOf('include.path')).toBeGreaterThanOrEqual(0)
+
+    // Check credentials in the separate config file
+    const credentialsFiles = (await fs.promises.readdir(runnerTemp)).filter(
+      f => f.startsWith('git-credentials-') && f.endsWith('.config')
+    )
+    expect(credentialsFiles.length).toBeGreaterThan(0)
+    const credentialsConfigPath = path.join(runnerTemp, credentialsFiles[0])
+    const credentialsContent = (
+      await fs.promises.readFile(credentialsConfigPath)
+    ).toString()
     expect(
-      configContent.indexOf(
+      credentialsContent.indexOf(
         `http.https://github.com/.extraheader AUTHORIZATION: basic ${basicCredential}`
       )
     ).toBeGreaterThanOrEqual(0)
@@ -463,8 +496,20 @@ describe('git-auth-helper tests', () => {
       const configContent = (
         await fs.promises.readFile(path.join(git.env['HOME'], '.gitconfig'))
       ).toString()
+      // Global config should have include.path pointing to credentials file
+      expect(configContent.indexOf('include.path')).toBeGreaterThanOrEqual(0)
+
+      // Check credentials in the separate config file
+      const credentialsFiles = (await fs.promises.readdir(runnerTemp)).filter(
+        f => f.startsWith('git-credentials-') && f.endsWith('.config')
+      )
+      expect(credentialsFiles.length).toBeGreaterThan(0)
+      const credentialsConfigPath = path.join(runnerTemp, credentialsFiles[0])
+      const credentialsContent = (
+        await fs.promises.readFile(credentialsConfigPath)
+      ).toString()
       expect(
-        configContent.indexOf(
+        credentialsContent.indexOf(
           `http.https://github.com/.extraheader AUTHORIZATION: basic ${basicCredential}`
         )
       ).toBeGreaterThanOrEqual(0)
@@ -550,11 +595,14 @@ describe('git-auth-helper tests', () => {
       await authHelper.configureSubmoduleAuth()
 
       // Assert
+      // Should get submodule config paths (1 call) and configure insteadOf (2 calls for two values)
       expect(mockSubmoduleForeach).toHaveBeenCalledTimes(4)
       expect(mockSubmoduleForeach.mock.calls[0][0]).toMatch(
         /unset-all.*insteadOf/
       )
-      expect(mockSubmoduleForeach.mock.calls[1][0]).toMatch(/http.*extraheader/)
+      expect(mockSubmoduleForeach.mock.calls[1][0]).toMatch(
+        /show-origin.*remote\.origin\.url/
+      )
       expect(mockSubmoduleForeach.mock.calls[2][0]).toMatch(
         /url.*insteadOf.*git@github.com:/
       )
@@ -589,11 +637,14 @@ describe('git-auth-helper tests', () => {
       await authHelper.configureSubmoduleAuth()
 
       // Assert
+      // Should get submodule config paths (1 call) and configure sshCommand (1 call)
       expect(mockSubmoduleForeach).toHaveBeenCalledTimes(3)
       expect(mockSubmoduleForeach.mock.calls[0][0]).toMatch(
         /unset-all.*insteadOf/
       )
-      expect(mockSubmoduleForeach.mock.calls[1][0]).toMatch(/http.*extraheader/)
+      expect(mockSubmoduleForeach.mock.calls[1][0]).toMatch(
+        /show-origin.*remote\.origin\.url/
+      )
       expect(mockSubmoduleForeach.mock.calls[2][0]).toMatch(/core\.sshCommand/)
     }
   )
@@ -660,19 +711,35 @@ describe('git-auth-helper tests', () => {
     await setup(removeAuth_removesToken)
     const authHelper = gitAuthHelper.createAuthHelper(git, settings)
     await authHelper.configureAuth()
-    let gitConfigContent = (
+
+    // Sanity check - verify includeIf entries exist in local config
+    let localConfigContent = (
       await fs.promises.readFile(localGitConfigPath)
     ).toString()
-    expect(gitConfigContent.indexOf('http.')).toBeGreaterThanOrEqual(0) // sanity check
+    expect(
+      localConfigContent.indexOf('includeIf.gitdir:')
+    ).toBeGreaterThanOrEqual(0)
+
+    // Sanity check - verify credentials file exists
+    let credentialsFiles = (await fs.promises.readdir(runnerTemp)).filter(
+      f => f.startsWith('git-credentials-') && f.endsWith('.config')
+    )
+    expect(credentialsFiles.length).toBe(1)
 
     // Act
     await authHelper.removeAuth()
 
-    // Assert git config
+    // Assert includeIf entries removed from local git config
-    gitConfigContent = (
+    localConfigContent = (
       await fs.promises.readFile(localGitConfigPath)
     ).toString()
-    expect(gitConfigContent.indexOf('http.')).toBeLessThan(0)
+    expect(localConfigContent.indexOf('includeIf.gitdir:')).toBeLessThan(0)
+
+    // Assert credentials config file deleted
+    credentialsFiles = (await fs.promises.readdir(runnerTemp)).filter(
+      f => f.startsWith('git-credentials-') && f.endsWith('.config')
+    )
+    expect(credentialsFiles.length).toBe(0)
   })
 
   const removeGlobalConfig_removesOverride =
@@ -715,6 +782,7 @@ async function setup(testName: string): Promise<void> {
   await fs.promises.mkdir(tempHomedir, {recursive: true})
   process.env['RUNNER_TEMP'] = runnerTemp
   process.env['HOME'] = tempHomedir
+  process.env['GITHUB_WORKSPACE'] = workspace
 
   // Create git config
   globalGitConfigPath = path.join(tempHomedir, '.gitconfig')
@@ -733,10 +801,20 @@ async function setup(testName: string): Promise<void> {
     checkout: jest.fn(),
     checkoutDetach: jest.fn(),
     config: jest.fn(
-      async (key: string, value: string, globalConfig?: boolean) => {
+      async (
-        const configPath = globalConfig
+        key: string,
+        value: string,
+        globalConfig?: boolean,
+        add?: boolean,
+        configFile?: string
+      ) => {
+        const configPath =
+          configFile ||
+          (globalConfig
             ? path.join(git.env['HOME'] || tempHomedir, '.gitconfig')
-          : localGitConfigPath
+            : localGitConfigPath)
+        // Ensure directory exists
+        await fs.promises.mkdir(path.dirname(configPath), {recursive: true})
         await fs.promises.appendFile(configPath, `\n${key} ${value}`)
       }
     ),
@@ -830,6 +908,7 @@ async function setup(testName: string): Promise<void> {
 
 async function getActualSshKeyPath(): Promise<string> {
   let actualTempFiles = (await fs.promises.readdir(runnerTemp))
+    .filter(x => !x.startsWith('git-credentials-')) // Exclude credentials config file
     .sort()
     .map(x => path.join(runnerTemp, x))
   if (actualTempFiles.length === 0) {
@@ -843,6 +922,7 @@ async function getActualSshKeyPath(): Promise<string> {
 
 async function getActualSshKnownHostsPath(): Promise<string> {
   let actualTempFiles = (await fs.promises.readdir(runnerTemp))
+    .filter(x => !x.startsWith('git-credentials-')) // Exclude credentials config file
     .sort()
     .map(x => path.join(runnerTemp, x))
   if (actualTempFiles.length === 0) {

__test__/verify-submodules-recursive.sh

@@ -17,7 +17,7 @@ fi
 
 echo "Testing persisted credential"
 pushd ./submodules-recursive/submodule-level-1/submodule-level-2
-git config --local --name-only --get-regexp http.+extraheader && git fetch
+git config --local --name-only --get-regexp '^includeIf\.' && git fetch
 if [ "$?" != "0" ]; then
     echo "Failed to validate persisted credential"
     popd

__test__/verify-submodules-true.sh

@@ -17,7 +17,7 @@ fi
 
 echo "Testing persisted credential"
 pushd ./submodules-true/submodule-level-1
-git config --local --name-only --get-regexp http.+extraheader && git fetch
+git config --local --name-only --get-regexp '^includeIf\.' && git fetch
 if [ "$?" != "0" ]; then
     echo "Failed to validate persisted credential"
     popd

dist/index.js

@@ -162,6 +162,8 @@ class GitAuthHelper {
         this.sshKeyPath = '';
         this.sshKnownHostsPath = '';
         this.temporaryHomePath = '';
+        this.credentialsConfigPath = ''; // Path to separate credentials config file in RUNNER_TEMP
+        this.credentialsIncludeKeys = []; // Track includeIf config keys for cleanup
         this.git = gitCommandManager;
         this.settings = gitSourceSettings || {};
         // Token auth header
@@ -187,6 +189,20 @@ class GitAuthHelper {
             yield this.configureToken();
         });
     }
+    getCredentialsConfigPath() {
+        return __awaiter(this, void 0, void 0, function* () {
+            if (this.credentialsConfigPath) {
+                return this.credentialsConfigPath;
+            }
+            const runnerTemp = process.env['RUNNER_TEMP'] || '';
+            assert.ok(runnerTemp, 'RUNNER_TEMP is not defined');
+            // Create a unique filename for this checkout instance
+            const configFileName = `git-credentials-${(0, uuid_1.v4)()}.config`;
+            this.credentialsConfigPath = path.join(runnerTemp, configFileName);
+            core.debug(`Credentials config path: ${this.credentialsConfigPath}`);
+            return this.credentialsConfigPath;
+        });
+    }
     configureTempGlobalConfig() {
         return __awaiter(this, void 0, void 0, function* () {
             var _a;
@@ -229,10 +245,10 @@ class GitAuthHelper {
     configureGlobalAuth() {
         return __awaiter(this, void 0, void 0, function* () {
             // 'configureTempGlobalConfig' noops if already set, just returns the path
-            const newGitConfigPath = yield this.configureTempGlobalConfig();
+            yield this.configureTempGlobalConfig();
             try {
                 // Configure the token
-                yield this.configureToken(newGitConfigPath, true);
+                yield this.configureToken(true);
                 // Configure HTTPS instead of SSH
                 yield this.git.tryConfigUnset(this.insteadOfKey, true);
                 if (!this.settings.sshKey) {
@@ -252,19 +268,37 @@ class GitAuthHelper {
     configureSubmoduleAuth() {
         return __awaiter(this, void 0, void 0, function* () {
             // Remove possible previous HTTPS instead of SSH
-            yield this.removeGitConfig(this.insteadOfKey, true);
+            yield this.removeSubmoduleGitConfig(this.insteadOfKey);
             if (this.settings.persistCredentials) {
-                // Configure a placeholder value. This approach avoids the credential being captured
+                // Credentials config path
-                // by process creation audit events, which are commonly logged. For more information,
+                const credentialsConfigPath = yield this.getCredentialsConfigPath();
-                // refer to https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/component-updates/command-line-process-auditing
+                // Container credentials config path
-                const output = yield this.git.submoduleForeach(
+                const containerCredentialsPath = path.posix.join('/github/runner_temp', path.basename(credentialsConfigPath));
-                // wrap the pipeline in quotes to make sure it's handled properly by submoduleForeach, rather than just the first part of the pipeline
+                // Container repo path
-                `sh -c "git config --local '${this.tokenConfigKey}' '${this.tokenPlaceholderConfigValue}' && git config --local --show-origin --name-only --get-regexp remote.origin.url"`, this.settings.nestedSubmodules);
+                const workingDirectory = this.git.getWorkingDirectory();
-                // Replace the placeholder
+                const githubWorkspace = process.env['GITHUB_WORKSPACE'];
+                assert.ok(githubWorkspace, 'GITHUB_WORKSPACE is not defined');
+                let relativePath = path.relative(githubWorkspace, workingDirectory);
+                relativePath = relativePath.replace(/\\/g, '/');
+                const containerRepoPath = path.posix.join('/github/workspace', relativePath);
+                // Get submodule config file paths.
+                // Use `--show-origin` to get the config file path for each submodule.
+                const output = yield this.git.submoduleForeach(`git config --local --show-origin --name-only --get-regexp remote.origin.url`, this.settings.nestedSubmodules);
+                // Extract config file paths from the output (lines starting with "file:").
                 const configPaths = output.match(/(?<=(^|\n)file:)[^\t]+(?=\tremote\.origin\.url)/g) || [];
+                // For each submodule, configure includeIf entries pointing to the shared credentials file.
+                // Configure both host and container paths to support Docker container actions.
                 for (const configPath of configPaths) {
-                    core.debug(`Replacing token placeholder in '${configPath}'`);
+                    // Submodule Git directory
-                    yield this.replaceTokenPlaceholder(configPath);
+                    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:${submoduleGitDir}.path`, credentialsConfigPath, false, false, configPath);
+                    // Configure container includeIf
+                    let relativeSubmoduleGitDir = path.relative(githubWorkspace, submoduleGitDir);
+                    relativeSubmoduleGitDir = relativeSubmoduleGitDir.replace(/\\/g, '/'); // Use forward slashes, even on Windows
+                    const containerSubmoduleGitDir = path.posix.join('/github/workspace', relativeSubmoduleGitDir);
+                    yield this.git.config(`includeIf.gitdir:${containerSubmoduleGitDir}.path`, containerCredentialsPath, false, false, configPath);
                 }
                 if (this.settings.sshKey) {
                     // Configure core.sshCommand
@@ -351,20 +385,44 @@ class GitAuthHelper {
             }
         });
     }
-    configureToken(configPath, globalConfig) {
+    configureToken(globalConfig) {
         return __awaiter(this, void 0, void 0, function* () {
-            // Validate args
+            // Get the credentials config file path in RUNNER_TEMP
-            assert.ok((configPath && globalConfig) || (!configPath && !globalConfig), 'Unexpected configureToken parameter combinations');
+            const credentialsConfigPath = yield this.getCredentialsConfigPath();
-            // Default config path
+            // Write placeholder to the separate credentials config file using git config.
-            if (!configPath && !globalConfig) {
+            // This approach avoids the credential being captured by process creation audit events,
-                configPath = path.join(this.git.getWorkingDirectory(), '.git', 'config');
+            // which are commonly logged. For more information, refer to
+            // https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/component-updates/command-line-process-auditing
+            yield this.git.config(this.tokenConfigKey, this.tokenPlaceholderConfigValue, false, false, credentialsConfigPath);
+            // Replace the placeholder in the credentials config file
+            yield this.replaceTokenPlaceholder(credentialsConfigPath);
+            // Add include or includeIf to reference the credentials config
+            if (globalConfig) {
+                // Global config file is temporary
+                yield this.git.config('include.path', credentialsConfigPath, true);
+            }
+            else {
+                // Host git directory
+                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:${gitDir}.path`;
+                yield this.git.config(hostIncludeKey, credentialsConfigPath);
+                this.credentialsIncludeKeys.push(hostIncludeKey);
+                // Container git directory
+                const githubWorkspace = process.env['GITHUB_WORKSPACE'];
+                assert.ok(githubWorkspace, 'GITHUB_WORKSPACE is not defined');
+                const workingDirectory = this.git.getWorkingDirectory();
+                let relativePath = path.relative(githubWorkspace, workingDirectory);
+                relativePath = relativePath.replace(/\\/g, '/'); // Use forward slashes, even on Windows
+                const containerGitDir = path.posix.join('/github/workspace', relativePath, '.git');
+                // Container credentials config path
+                const containerCredentialsPath = path.posix.join('/github/runner_temp', path.basename(credentialsConfigPath));
+                // Configure container includeIf
+                const containerIncludeKey = `includeIf.gitdir:${containerGitDir}.path`;
+                yield this.git.config(containerIncludeKey, containerCredentialsPath);
+                this.credentialsIncludeKeys.push(containerIncludeKey);
             }
-            // Configure a placeholder value. This approach avoids the credential being captured
-            // by process creation audit events, which are commonly logged. For more information,
-            // refer to https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/component-updates/command-line-process-auditing
-            yield this.git.config(this.tokenConfigKey, this.tokenPlaceholderConfigValue, globalConfig);
-            // Replace the placeholder
-            yield this.replaceTokenPlaceholder(configPath || '');
         });
     }
     replaceTokenPlaceholder(configPath) {
@@ -407,26 +465,48 @@ class GitAuthHelper {
             }
             // SSH command
             yield this.removeGitConfig(SSH_COMMAND_KEY);
+            yield this.removeSubmoduleGitConfig(SSH_COMMAND_KEY);
         });
     }
     removeToken() {
         return __awaiter(this, void 0, void 0, function* () {
-            // HTTP extra header
+            var _a;
+            // Remove HTTP extra header
             yield this.removeGitConfig(this.tokenConfigKey);
+            yield this.removeSubmoduleGitConfig(this.tokenConfigKey);
+            // Remove includeIf
+            for (const includeKey of this.credentialsIncludeKeys) {
+                yield this.removeGitConfig(includeKey);
+            }
+            this.credentialsIncludeKeys = [];
+            // Remove submodule includeIf
+            yield this.git.submoduleForeach(`sh -c "git config --local --get-regexp '^includeIf\\.' && git config --local --remove-section includeIf || :"`, true);
+            // Remove credentials config file
+            if (this.credentialsConfigPath) {
+                try {
+                    yield io.rmRF(this.credentialsConfigPath);
+                }
+                catch (err) {
+                    core.debug(`${(_a = err === null || err === void 0 ? void 0 : err.message) !== null && _a !== void 0 ? _a : err}`);
+                    core.warning(`Failed to remove credentials config '${this.credentialsConfigPath}'`);
+                }
+            }
         });
     }
-    removeGitConfig(configKey_1) {
+    removeGitConfig(configKey) {
-        return __awaiter(this, arguments, void 0, function* (configKey, submoduleOnly = false) {
+        return __awaiter(this, void 0, void 0, function* () {
-            if (!submoduleOnly) {
             if ((yield this.git.configExists(configKey)) &&
                 !(yield this.git.tryConfigUnset(configKey))) {
                 // Load the config contents
                 core.warning(`Failed to remove '${configKey}' from the git config`);
             }
+        });
     }
+    removeSubmoduleGitConfig(configKey) {
+        return __awaiter(this, void 0, void 0, function* () {
             const pattern = regexpHelper.escape(configKey);
             yield this.git.submoduleForeach(
-            // wrap the pipeline in quotes to make sure it's handled properly by submoduleForeach, rather than just the first part of the pipeline
+            // Wrap the pipeline in quotes to make sure it's handled properly by submoduleForeach, rather than just the first part of the pipeline.
             `sh -c "git config --local --name-only --get-regexp '${pattern}' && git config --local --unset-all '${configKey}' || :"`, true);
         });
     }
@@ -627,9 +707,15 @@ class GitCommandManager {
             yield this.execGit(args);
         });
     }
-    config(configKey, configValue, globalConfig, add) {
+    config(configKey, configValue, globalConfig, add, configFile) {
         return __awaiter(this, void 0, void 0, function* () {
-            const args = ['config', globalConfig ? '--global' : '--local'];
+            const args = ['config'];
+            if (configFile) {
+                args.push('--file', configFile);
+            }
+            else {
+                args.push(globalConfig ? '--global' : '--local');
+            }
             if (add) {
                 args.push('--add');
             }

src/git-auth-helper.ts

@@ -43,6 +43,8 @@ class GitAuthHelper {
   private sshKeyPath = ''
   private sshKnownHostsPath = ''
   private temporaryHomePath = ''
+  private credentialsConfigPath = '' // Path to separate credentials config file in RUNNER_TEMP
+  private credentialsIncludeKeys: string[] = [] // Track includeIf config keys for cleanup
 
   constructor(
     gitCommandManager: IGitCommandManager,
@@ -81,6 +83,22 @@ class GitAuthHelper {
     await this.configureToken()
   }
 
+  private async getCredentialsConfigPath(): Promise<string> {
+    if (this.credentialsConfigPath) {
+      return this.credentialsConfigPath
+    }
+
+    const runnerTemp = process.env['RUNNER_TEMP'] || ''
+    assert.ok(runnerTemp, 'RUNNER_TEMP is not defined')
+
+    // Create a unique filename for this checkout instance
+    const configFileName = `git-credentials-${uuid()}.config`
+    this.credentialsConfigPath = path.join(runnerTemp, configFileName)
+
+    core.debug(`Credentials config path: ${this.credentialsConfigPath}`)
+    return this.credentialsConfigPath
+  }
+
   async configureTempGlobalConfig(): Promise<string> {
     // Already setup global config
     if (this.temporaryHomePath?.length > 0) {
@@ -126,10 +144,10 @@ class GitAuthHelper {
 
   async configureGlobalAuth(): Promise<void> {
     // 'configureTempGlobalConfig' noops if already set, just returns the path
-    const newGitConfigPath = await this.configureTempGlobalConfig()
+    await this.configureTempGlobalConfig()
     try {
       // Configure the token
-      await this.configureToken(newGitConfigPath, true)
+      await this.configureToken(true)
 
       // Configure HTTPS instead of SSH
       await this.git.tryConfigUnset(this.insteadOfKey, true)
@@ -150,24 +168,73 @@ class GitAuthHelper {
 
   async configureSubmoduleAuth(): Promise<void> {
     // Remove possible previous HTTPS instead of SSH
-    await this.removeGitConfig(this.insteadOfKey, true)
+    await this.removeSubmoduleGitConfig(this.insteadOfKey)
 
     if (this.settings.persistCredentials) {
-      // Configure a placeholder value. This approach avoids the credential being captured
+      // Credentials config path
-      // by process creation audit events, which are commonly logged. For more information,
+      const credentialsConfigPath = await this.getCredentialsConfigPath()
-      // refer to https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/component-updates/command-line-process-auditing
+
+      // Container credentials config path
+      const containerCredentialsPath = path.posix.join(
+        '/github/runner_temp',
+        path.basename(credentialsConfigPath)
+      )
+
+      // Container repo path
+      const workingDirectory = this.git.getWorkingDirectory()
+      const githubWorkspace = process.env['GITHUB_WORKSPACE']
+      assert.ok(githubWorkspace, 'GITHUB_WORKSPACE is not defined')
+      let relativePath = path.relative(githubWorkspace, workingDirectory)
+      relativePath = relativePath.replace(/\\/g, '/')
+      const containerRepoPath = path.posix.join(
+        '/github/workspace',
+        relativePath
+      )
+
+      // Get submodule config file paths.
+      // Use `--show-origin` to get the config file path for each submodule.
       const output = await this.git.submoduleForeach(
-        // wrap the pipeline in quotes to make sure it's handled properly by submoduleForeach, rather than just the first part of the pipeline
+        `git config --local --show-origin --name-only --get-regexp remote.origin.url`,
-        `sh -c "git config --local '${this.tokenConfigKey}' '${this.tokenPlaceholderConfigValue}' && git config --local --show-origin --name-only --get-regexp remote.origin.url"`,
         this.settings.nestedSubmodules
       )
 
-      // Replace the placeholder
+      // Extract config file paths from the output (lines starting with "file:").
-      const configPaths: string[] =
+      const configPaths =
         output.match(/(?<=(^|\n)file:)[^\t]+(?=\tremote\.origin\.url)/g) || []
+
+      // For each submodule, configure includeIf entries pointing to the shared credentials file.
+      // Configure both host and container paths to support Docker container actions.
       for (const configPath of configPaths) {
-        core.debug(`Replacing token placeholder in '${configPath}'`)
+        // Submodule Git directory
-        await this.replaceTokenPlaceholder(configPath)
+        let submoduleGitDir = path.dirname(configPath) // The config file is at .git/modules/submodule-name/config
+        submoduleGitDir = submoduleGitDir.replace(/\\/g, '/') // Use forward slashes, even on Windows
+
+        // Configure host includeIf
+        await this.git.config(
+          `includeIf.gitdir:${submoduleGitDir}.path`,
+          credentialsConfigPath,
+          false,
+          false,
+          configPath
+        )
+
+        // Configure container includeIf
+        let relativeSubmoduleGitDir = path.relative(
+          githubWorkspace,
+          submoduleGitDir
+        )
+        relativeSubmoduleGitDir = relativeSubmoduleGitDir.replace(/\\/g, '/') // Use forward slashes, even on Windows
+        const containerSubmoduleGitDir = path.posix.join(
+          '/github/workspace',
+          relativeSubmoduleGitDir
+        )
+        await this.git.config(
+          `includeIf.gitdir:${containerSubmoduleGitDir}.path`,
+          containerCredentialsPath,
+          false,
+          false,
+          configPath
+        )
       }
 
       if (this.settings.sshKey) {
@@ -272,32 +339,62 @@ class GitAuthHelper {
     }
   }
 
-  private async configureToken(
+  private async configureToken(globalConfig?: boolean): Promise<void> {
-    configPath?: string,
+    // Get the credentials config file path in RUNNER_TEMP
-    globalConfig?: boolean
+    const credentialsConfigPath = await this.getCredentialsConfigPath()
-  ): Promise<void> {
-    // Validate args
-    assert.ok(
-      (configPath && globalConfig) || (!configPath && !globalConfig),
-      'Unexpected configureToken parameter combinations'
-    )
 
-    // Default config path
+    // Write placeholder to the separate credentials config file using git config.
-    if (!configPath && !globalConfig) {
+    // This approach avoids the credential being captured by process creation audit events,
-      configPath = path.join(this.git.getWorkingDirectory(), '.git', 'config')
+    // which are commonly logged. For more information, refer to
-    }
+    // https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/component-updates/command-line-process-auditing
-
-    // Configure a placeholder value. This approach avoids the credential being captured
-    // by process creation audit events, which are commonly logged. For more information,
-    // refer to https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/component-updates/command-line-process-auditing
     await this.git.config(
       this.tokenConfigKey,
       this.tokenPlaceholderConfigValue,
-      globalConfig
+      false,
+      false,
+      credentialsConfigPath
     )
 
-    // Replace the placeholder
+    // Replace the placeholder in the credentials config file
-    await this.replaceTokenPlaceholder(configPath || '')
+    await this.replaceTokenPlaceholder(credentialsConfigPath)
+
+    // Add include or includeIf to reference the credentials config
+    if (globalConfig) {
+      // Global config file is temporary
+      await this.git.config('include.path', credentialsConfigPath, true)
+    } else {
+      // Host git directory
+      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:${gitDir}.path`
+      await this.git.config(hostIncludeKey, credentialsConfigPath)
+      this.credentialsIncludeKeys.push(hostIncludeKey)
+
+      // Container git directory
+      const githubWorkspace = process.env['GITHUB_WORKSPACE']
+      assert.ok(githubWorkspace, 'GITHUB_WORKSPACE is not defined')
+      const workingDirectory = this.git.getWorkingDirectory()
+      let relativePath = path.relative(githubWorkspace, workingDirectory)
+      relativePath = relativePath.replace(/\\/g, '/') // Use forward slashes, even on Windows
+      const containerGitDir = path.posix.join(
+        '/github/workspace',
+        relativePath,
+        '.git'
+      )
+
+      // Container credentials config path
+      const containerCredentialsPath = path.posix.join(
+        '/github/runner_temp',
+        path.basename(credentialsConfigPath)
+      )
+
+      // Configure container includeIf
+      const containerIncludeKey = `includeIf.gitdir:${containerGitDir}.path`
+      await this.git.config(containerIncludeKey, containerCredentialsPath)
+      this.credentialsIncludeKeys.push(containerIncludeKey)
+    }
   }
 
   private async replaceTokenPlaceholder(configPath: string): Promise<void> {
@@ -343,18 +440,40 @@ class GitAuthHelper {
 
     // SSH command
     await this.removeGitConfig(SSH_COMMAND_KEY)
+    await this.removeSubmoduleGitConfig(SSH_COMMAND_KEY)
   }
 
   private async removeToken(): Promise<void> {
-    // HTTP extra header
+    // Remove HTTP extra header
     await this.removeGitConfig(this.tokenConfigKey)
+    await this.removeSubmoduleGitConfig(this.tokenConfigKey)
+
+    // Remove includeIf
+    for (const includeKey of this.credentialsIncludeKeys) {
+      await this.removeGitConfig(includeKey)
+    }
+    this.credentialsIncludeKeys = []
+
+    // Remove submodule includeIf
+    await this.git.submoduleForeach(
+      `sh -c "git config --local --get-regexp '^includeIf\\.' && git config --local --remove-section includeIf || :"`,
+      true
+    )
+
+    // Remove credentials config file
+    if (this.credentialsConfigPath) {
+      try {
+        await io.rmRF(this.credentialsConfigPath)
+      } catch (err) {
+        core.debug(`${(err as any)?.message ?? err}`)
+        core.warning(
+          `Failed to remove credentials config '${this.credentialsConfigPath}'`
+        )
+      }
+    }
   }
 
-  private async removeGitConfig(
+  private async removeGitConfig(configKey: string): Promise<void> {
-    configKey: string,
-    submoduleOnly: boolean = false
-  ): Promise<void> {
-    if (!submoduleOnly) {
     if (
       (await this.git.configExists(configKey)) &&
       !(await this.git.tryConfigUnset(configKey))
@@ -364,9 +483,10 @@ class GitAuthHelper {
     }
   }
 
+  private async removeSubmoduleGitConfig(configKey: string): Promise<void> {
     const pattern = regexpHelper.escape(configKey)
     await this.git.submoduleForeach(
-      // wrap the pipeline in quotes to make sure it's handled properly by submoduleForeach, rather than just the first part of the pipeline
+      // Wrap the pipeline in quotes to make sure it's handled properly by submoduleForeach, rather than just the first part of the pipeline.
       `sh -c "git config --local --name-only --get-regexp '${pattern}' && git config --local --unset-all '${configKey}' || :"`,
       true
     )

src/git-command-manager.ts

@@ -28,7 +28,8 @@ export interface IGitCommandManager {
     configKey: string,
     configValue: string,
     globalConfig?: boolean,
-    add?: boolean
+    add?: boolean,
+    configFile?: string
   ): Promise<void>
   configExists(configKey: string, globalConfig?: boolean): Promise<boolean>
   fetch(
@@ -223,9 +224,15 @@ class GitCommandManager {
     configKey: string,
     configValue: string,
     globalConfig?: boolean,
-    add?: boolean
+    add?: boolean,
+    configFile?: string
   ): Promise<void> {
-    const args: string[] = ['config', globalConfig ? '--global' : '--local']
+    const args: string[] = ['config']
+    if (configFile) {
+      args.push('--file', configFile)
+    } else {
+      args.push(globalConfig ? '--global' : '--local')
+    }
     if (add) {
       args.push('--add')
     }