v6

src/git-auth-helper.ts

@@ -43,6 +43,7 @@ class GitAuthHelper {
   private sshKeyPath = ''
   private sshKnownHostsPath = ''
   private temporaryHomePath = ''
+  private credentialsConfigPath = '' // Path to separate credentials config file in RUNNER_TEMP
 
   constructor(
     gitCommandManager: IGitCommandManager,
@@ -126,16 +127,21 @@ 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)
       if (!this.settings.sshKey) {
         for (const insteadOfValue of this.insteadOfValues) {
-          await this.git.config(this.insteadOfKey, insteadOfValue, true, true)
+          await this.git.config(
+            this.insteadOfKey,
+            insteadOfValue,
+            true, // globalConfig?
+            true // add?
+          )
         }
       }
     } catch (err) {
@@ -150,24 +156,60 @@ 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
-      // 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
-      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
-        `sh -c "git config --local '${this.tokenConfigKey}' '${this.tokenPlaceholderConfigValue}' && git config --local --show-origin --name-only --get-regexp remote.origin.url"`,
+      // Get the credentials config file path in RUNNER_TEMP
+      const credentialsConfigPath = this.getCredentialsConfigPath()
+
+      // Container credentials config path
+      const containerCredentialsPath = path.posix.join(
+        '/github/runner_temp',
+        path.basename(credentialsConfigPath)
+      )
+
+      // Get submodule config file paths.
+      const configPaths = await this.git.getSubmoduleConfigPaths(
         this.settings.nestedSubmodules
       )
 
-      // Replace the placeholder
-      const configPaths: string[] =
-        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 '${configPath}'`)
-        await this.replaceTokenPlaceholder(configPath)
+        // Submodule Git directory
+        let submoduleGitDir = path.dirname(configPath) // The config file is at .git/modules/submodule-name/config
+        submoduleGitDir = submoduleGitDir.replace(/\\/g, '/') // Use forward slashes, even on Windows
+
+        // Configure host includeIf
+        await this.git.config(
+          `includeIf.gitdir:${submoduleGitDir}.path`,
+          credentialsConfigPath,
+          false, // globalConfig?
+          false, // add?
+          configPath
+        )
+
+        // Container submodule git directory
+        const githubWorkspace = process.env['GITHUB_WORKSPACE']
+        assert.ok(githubWorkspace, 'GITHUB_WORKSPACE is not defined')
+        let relativeSubmoduleGitDir = path.relative(
+          githubWorkspace,
+          submoduleGitDir
+        )
+        relativeSubmoduleGitDir = relativeSubmoduleGitDir.replace(/\\/g, '/') // Use forward slashes, even on Windows
+        const containerSubmoduleGitDir = path.posix.join(
+          '/github/workspace',
+          relativeSubmoduleGitDir
+        )
+
+        // Configure container includeIf
+        await this.git.config(
+          `includeIf.gitdir:${containerSubmoduleGitDir}.path`,
+          containerCredentialsPath,
+          false, // globalConfig?
+          false, // add?
+          configPath
+        )
       }
 
       if (this.settings.sshKey) {
@@ -201,6 +243,10 @@ class GitAuthHelper {
     }
   }
 
+  /**
+   * Configures SSH authentication by writing the SSH key and known hosts,
+   * and setting up the GIT_SSH_COMMAND environment variable.
+   */
   private async configureSsh(): Promise<void> {
     if (!this.settings.sshKey) {
       return
@@ -272,57 +318,127 @@ class GitAuthHelper {
     }
   }
 
-  private async configureToken(
-    configPath?: string,
-    globalConfig?: boolean
-  ): Promise<void> {
-    // Validate args
-    assert.ok(
-      (configPath && globalConfig) || (!configPath && !globalConfig),
-      'Unexpected configureToken parameter combinations'
-    )
+  /**
+   * Configures token-based authentication by creating a credentials config file
+   * and setting up includeIf entries to reference it.
+   * @param globalConfig Whether to configure global config instead of local
+   */
+  private async configureToken(globalConfig?: boolean): Promise<void> {
+    // Get the credentials config file path in RUNNER_TEMP
+    const credentialsConfigPath = this.getCredentialsConfigPath()
 
-    // Default config path
-    if (!configPath && !globalConfig) {
-      configPath = path.join(this.git.getWorkingDirectory(), '.git', 'config')
-    }
-
-    // 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
+    // Write placeholder to the separate credentials config file using git config.
+    // 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, // globalConfig?
+      false, // add?
+      credentialsConfigPath
     )
 
-    // Replace the placeholder
-    await this.replaceTokenPlaceholder(configPath || '')
-  }
-
-  private async replaceTokenPlaceholder(configPath: string): Promise<void> {
-    assert.ok(configPath, 'configPath is not defined')
-    let content = (await fs.promises.readFile(configPath)).toString()
+    // Replace the placeholder in the credentials config file
+    let content = (await fs.promises.readFile(credentialsConfigPath)).toString()
     const placeholderIndex = content.indexOf(this.tokenPlaceholderConfigValue)
     if (
       placeholderIndex < 0 ||
       placeholderIndex != content.lastIndexOf(this.tokenPlaceholderConfigValue)
     ) {
-      throw new Error(`Unable to replace auth placeholder in ${configPath}`)
+      throw new Error(
+        `Unable to replace auth placeholder in ${credentialsConfigPath}`
+      )
     }
     assert.ok(this.tokenConfigValue, 'tokenConfigValue is not defined')
     content = content.replace(
       this.tokenPlaceholderConfigValue,
       this.tokenConfigValue
     )
-    await fs.promises.writeFile(configPath, content)
+    await fs.promises.writeFile(credentialsConfigPath, content)
+
+    // Add include or includeIf to reference the credentials config
+    if (globalConfig) {
+      // Global config file is temporary
+      await this.git.config(
+        'include.path',
+        credentialsConfigPath,
+        true // globalConfig?
+      )
+    } else {
+      // Host git directory
+      let gitDir = path.join(this.git.getWorkingDirectory(), '.git')
+      gitDir = gitDir.replace(/\\/g, '/') // Use forward slashes, even on Windows
+
+      // Configure host includeIf
+      const hostIncludeKey = `includeIf.gitdir:${gitDir}.path`
+      await this.git.config(hostIncludeKey, credentialsConfigPath)
+
+      // Configure host includeIf for worktrees
+      const hostWorktreeIncludeKey = `includeIf.gitdir:${gitDir}/worktrees/*.path`
+      await this.git.config(hostWorktreeIncludeKey, credentialsConfigPath)
+
+      // Container git directory
+      const workingDirectory = this.git.getWorkingDirectory()
+      const githubWorkspace = process.env['GITHUB_WORKSPACE']
+      assert.ok(githubWorkspace, 'GITHUB_WORKSPACE is not defined')
+      let relativePath = path.relative(githubWorkspace, workingDirectory)
+      relativePath = relativePath.replace(/\\/g, '/') // Use forward slashes, even on Windows
+      const containerGitDir = path.posix.join(
+        '/github/workspace',
+        relativePath,
+        '.git'
+      )
+
+      // Container credentials config path
+      const containerCredentialsPath = path.posix.join(
+        '/github/runner_temp',
+        path.basename(credentialsConfigPath)
+      )
+
+      // Configure container includeIf
+      const containerIncludeKey = `includeIf.gitdir:${containerGitDir}.path`
+      await this.git.config(containerIncludeKey, containerCredentialsPath)
+
+      // Configure container includeIf for worktrees
+      const containerWorktreeIncludeKey = `includeIf.gitdir:${containerGitDir}/worktrees/*.path`
+      await this.git.config(
+        containerWorktreeIncludeKey,
+        containerCredentialsPath
+      )
+    }
   }
 
+  /**
+   * Gets or creates the path to the credentials config file in RUNNER_TEMP.
+   * @returns The absolute path to the credentials config file
+   */
+  private getCredentialsConfigPath(): 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: ${this.credentialsConfigPath}`)
+    return this.credentialsConfigPath
+  }
+
+  /**
+   * Removes SSH authentication configuration by cleaning up SSH keys,
+   * known hosts files, and SSH command configurations.
+   */
   private async removeSsh(): Promise<void> {
     // SSH key
     const keyPath = this.sshKeyPath || stateHelper.SshKeyPath
     if (keyPath) {
       try {
+        core.info(`Removing SSH key '${keyPath}'`)
         await io.rmRF(keyPath)
       } catch (err) {
         core.debug(`${(err as any)?.message ?? err}`)
@@ -335,88 +451,91 @@ class GitAuthHelper {
       this.sshKnownHostsPath || stateHelper.SshKnownHostsPath
     if (knownHostsPath) {
       try {
+        core.info(`Removing SSH known hosts '${knownHostsPath}'`)
         await io.rmRF(knownHostsPath)
-      } catch {
-        // Intentionally empty
+      } catch (err) {
+        core.debug(`${(err as any)?.message ?? err}`)
+        core.warning(`Failed to remove SSH known hosts '${knownHostsPath}'`)
       }
     }
 
     // SSH command
+    core.info('Removing SSH command configuration')
     await this.removeGitConfig(SSH_COMMAND_KEY)
+    await this.removeSubmoduleGitConfig(SSH_COMMAND_KEY)
   }
 
+  /**
+   * Removes token-based authentication by cleaning up HTTP headers,
+   * includeIf entries, and credentials config files.
+   */
   private async removeToken(): Promise<void> {
-    // Remove HTTP extra header from local git config and submodule configs
+    // Remove HTTP extra header
+    core.info('Removing HTTP extra header')
     await this.removeGitConfig(this.tokenConfigKey)
+    await this.removeSubmoduleGitConfig(this.tokenConfigKey)
 
-    //
-    // Cleanup actions/checkout@v6 style credentials
-    //
-    const skipV6Cleanup = process.env['ACTIONS_CHECKOUT_SKIP_V6_CLEANUP']
-    if (skipV6Cleanup === '1' || skipV6Cleanup?.toLowerCase() === 'true') {
-      core.debug(
-        'Skipping v6 style cleanup due to ACTIONS_CHECKOUT_SKIP_V6_CLEANUP'
-      )
-      return
+    // Collect credentials config paths that need to be removed
+    const credentialsPaths = new Set<string>()
+
+    // Remove includeIf entries that point to git-credentials-*.config files
+    core.info('Removing includeIf entries pointing to credentials config files')
+    const mainCredentialsPaths = await this.removeIncludeIfCredentials()
+    mainCredentialsPaths.forEach(path => credentialsPaths.add(path))
+
+    // Remove submodule includeIf entries that point to git-credentials-*.config files
+    const submoduleConfigPaths = await this.git.getSubmoduleConfigPaths(true)
+    for (const configPath of submoduleConfigPaths) {
+      const submoduleCredentialsPaths =
+        await this.removeIncludeIfCredentials(configPath)
+      submoduleCredentialsPaths.forEach(path => credentialsPaths.add(path))
     }
 
-    try {
-      // Collect credentials config paths that need to be removed
-      const credentialsPaths = new Set<string>()
-
-      // Remove includeIf entries that point to git-credentials-*.config files
-      const mainCredentialsPaths = await this.removeIncludeIfCredentials()
-      mainCredentialsPaths.forEach(path => credentialsPaths.add(path))
-
-      // Remove submodule includeIf entries that point to git-credentials-*.config files
-      try {
-        const submoduleConfigPaths =
-          await this.git.getSubmoduleConfigPaths(true)
-        for (const configPath of submoduleConfigPaths) {
-          const submoduleCredentialsPaths =
-            await this.removeIncludeIfCredentials(configPath)
-          submoduleCredentialsPaths.forEach(path => credentialsPaths.add(path))
+    // Remove credentials config files
+    for (const credentialsPath of credentialsPaths) {
+      // Only remove credentials config files if they are under RUNNER_TEMP
+      const runnerTemp = process.env['RUNNER_TEMP']
+      assert.ok(runnerTemp, 'RUNNER_TEMP is not defined')
+      if (credentialsPath.startsWith(runnerTemp)) {
+        try {
+          core.info(`Removing credentials config '${credentialsPath}'`)
+          await io.rmRF(credentialsPath)
+        } catch (err) {
+          core.debug(`${(err as any)?.message ?? err}`)
+          core.warning(
+            `Failed to remove credentials config '${credentialsPath}'`
+          )
         }
-      } catch (err) {
-        core.debug(`Unable to get submodule config paths: ${err}`)
+      } else {
+        core.debug(
+          `Skipping removal of credentials config '${credentialsPath}' - not under RUNNER_TEMP`
+        )
       }
-
-      // Remove credentials config files
-      for (const credentialsPath of credentialsPaths) {
-        // Only remove credentials config files if they are under RUNNER_TEMP
-        const runnerTemp = process.env['RUNNER_TEMP']
-        if (runnerTemp && credentialsPath.startsWith(runnerTemp)) {
-          try {
-            await io.rmRF(credentialsPath)
-          } catch (err) {
-            core.debug(
-              `Failed to remove credentials config '${credentialsPath}': ${err}`
-            )
-          }
-        }
-      }
-    } catch (err) {
-      core.debug(`Failed to cleanup v6 style credentials: ${err}`)
     }
   }
 
-  private async removeGitConfig(
-    configKey: string,
-    submoduleOnly: boolean = false
-  ): Promise<void> {
-    if (!submoduleOnly) {
-      if (
-        (await this.git.configExists(configKey)) &&
-        !(await this.git.tryConfigUnset(configKey))
-      ) {
-        // Load the config contents
-        core.warning(`Failed to remove '${configKey}' from the git config`)
-      }
+  /**
+   * Removes a git config key from the local repository config.
+   * @param configKey The git config key to remove
+   */
+  private async removeGitConfig(configKey: string): Promise<void> {
+    if (
+      (await this.git.configExists(configKey)) &&
+      !(await this.git.tryConfigUnset(configKey))
+    ) {
+      // Load the config contents
+      core.warning(`Failed to remove '${configKey}' from the git config`)
     }
+  }
 
+  /**
+   * Removes a git config key from all submodule configs.
+   * @param configKey The git config key to remove
+   */
+  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
     )
@@ -424,7 +543,6 @@ class GitAuthHelper {
 
   /**
    * Removes includeIf entries that point to git-credentials-*.config files.
-   * This handles cleanup of credentials configured by newer versions of the action.
    * @param configPath Optional path to a specific git config file to operate on
    * @returns Array of unique credentials config file paths that were found and removed
    */
@@ -460,16 +578,18 @@ class GitAuthHelper {
       }
     } catch (err) {
       // Ignore errors - this is cleanup code
-      core.debug(
-        `Error during includeIf cleanup${configPath ? ` for ${configPath}` : ''}: ${err}`
-      )
+      if (configPath) {
+        core.debug(`Error during includeIf cleanup for ${configPath}: ${err}`)
+      } else {
+        core.debug(`Error during includeIf cleanup: ${err}`)
+      }
     }
 
     return Array.from(credentialsPaths)
   }
 
   /**
-   * Tests if a path matches the git-credentials-*.config pattern used by newer versions.
+   * Tests if a path matches the git-credentials-*.config pattern.
    * @param path The path to test
    * @returns True if the path matches the credentials config pattern
    */

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(
@@ -36,14 +37,13 @@ export interface IGitCommandManager {
     options: {
       filter?: string
       fetchDepth?: number
-      fetchTags?: boolean
       showProgress?: boolean
     }
   ): Promise<void>
   getDefaultBranch(repositoryUrl: string): Promise<string>
   getSubmoduleConfigPaths(recursive: boolean): Promise<string[]>
   getWorkingDirectory(): string
-  init(): Promise<void>
+  init(objectFormat?: string): Promise<void>
   isDetached(): Promise<boolean>
   lfsFetch(ref: string): Promise<void>
   lfsInstall(): Promise<void>
@@ -240,9 +240,15 @@ 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')
     }
@@ -273,14 +279,13 @@ class GitCommandManager {
     options: {
       filter?: string
       fetchDepth?: number
-      fetchTags?: boolean
       showProgress?: boolean
     }
   ): Promise<void> {
     const args = ['-c', 'protocol.version=2', 'fetch']
-    if (!refSpec.some(x => x === refHelper.tagsRefSpec) && !options.fetchTags) {
-      args.push('--no-tags')
-    }
+    // Always use --no-tags for explicit control over tag fetching
+    // Tags are fetched explicitly via refspec when needed
+    args.push('--no-tags')
 
     args.push('--prune', '--no-recurse-submodules')
     if (options.showProgress) {
@@ -359,8 +364,14 @@ class GitCommandManager {
     return this.workingDirectory
   }
 
-  async init(): Promise<void> {
-    await this.execGit(['init', this.workingDirectory])
+  async init(objectFormat?: string): Promise<void> {
+    const args = ['init']
+    if (objectFormat === 'sha256') {
+      args.push('--object-format=sha256')
+    }
+    args.push(this.workingDirectory)
+
+    await this.execGit(args)
   }
 
   async isDetached(): Promise<boolean> {
@@ -723,7 +734,19 @@ class GitCommandManager {
       }
     }
     // Set the user agent
-    const gitHttpUserAgent = `git/${this.gitVersion} (github-actions-checkout)`
+    let gitHttpUserAgent = `git/${this.gitVersion} (github-actions-checkout)`
+
+    // Append orchestration ID if set
+    const orchId = process.env['ACTIONS_ORCHESTRATION_ID']
+    if (orchId) {
+      // Sanitize the orchestration ID to ensure it contains only valid characters
+      // Valid characters: 0-9, a-z, _, -, .
+      const sanitizedId = orchId.replace(/[^a-z0-9_.-]/gi, '_')
+      if (sanitizedId) {
+        gitHttpUserAgent = `${gitHttpUserAgent} actions_orchestration_id/${sanitizedId}`
+      }
+    }
+
     core.debug(`Set git useragent to: ${gitHttpUserAgent}`)
     this.gitEnv['GIT_HTTP_USER_AGENT'] = gitHttpUserAgent
   }

src/git-source-provider.ts

@@ -109,8 +109,25 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
     if (
       !fsHelper.directoryExistsSync(path.join(settings.repositoryPath, '.git'))
     ) {
+      core.startGroup('Determining repository object format')
+      const objectFormatResult =
+        await githubApiHelper.tryGetRepositoryObjectFormat(
+          settings.authToken,
+          settings.repositoryOwner,
+          settings.repositoryName,
+          settings.githubServerUrl,
+          settings.commit
+        )
+      const objectFormat = objectFormatResult.succeeded
+        ? objectFormatResult.format
+        : ''
+      if (objectFormat === 'sha256') {
+        core.info('Detected SHA-256 repository object format')
+      }
+      core.endGroup()
+
       core.startGroup('Initializing the repository')
-      await git.init()
+      await git.init(objectFormat)
       await git.remoteAdd('origin', repositoryUrl)
       core.endGroup()
     }
@@ -159,7 +176,6 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
     const fetchOptions: {
       filter?: string
       fetchDepth?: number
-      fetchTags?: boolean
       showProgress?: boolean
     } = {}
 
@@ -182,12 +198,35 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
       if (!(await refHelper.testRef(git, settings.ref, settings.commit))) {
         refSpec = refHelper.getRefSpec(settings.ref, settings.commit)
         await git.fetch(refSpec, fetchOptions)
+
+        // Verify the ref now matches. For branches, the targeted fetch above brings
+        // in the specific commit. For tags (fetched by ref), this will fail if
+        // the tag was moved after the workflow was triggered.
+        if (!(await refHelper.testRef(git, settings.ref, settings.commit))) {
+          throw new Error(
+            `The ref '${settings.ref}' does not point to the expected commit '${settings.commit}'. ` +
+              `The ref may have been updated after the workflow was triggered.`
+          )
+        }
       }
     } else {
       fetchOptions.fetchDepth = settings.fetchDepth
-      fetchOptions.fetchTags = settings.fetchTags
-      const refSpec = refHelper.getRefSpec(settings.ref, settings.commit)
+      const refSpec = refHelper.getRefSpec(
+        settings.ref,
+        settings.commit,
+        settings.fetchTags
+      )
       await git.fetch(refSpec, fetchOptions)
+
+      // For tags, verify the ref still points to the expected commit.
+      // Tags are fetched by ref (not commit), so if a tag was moved after the
+      // workflow was triggered, we would silently check out the wrong commit.
+      if (!(await refHelper.testRef(git, settings.ref, settings.commit))) {
+        throw new Error(
+          `The ref '${settings.ref}' does not point to the expected commit '${settings.commit}'. ` +
+            `The ref may have been updated after the workflow was triggered.`
+        )
+      }
     }
     core.endGroup()
 

src/github-api-helper.ts

@@ -11,6 +11,11 @@ import {getServerApiUrl} from './url-helper'
 
 const IS_WINDOWS = process.platform === 'win32'
 
+export interface RepositoryObjectFormatResult {
+  format: string
+  succeeded: boolean
+}
+
 export async function downloadRepository(
   authToken: string,
   owner: string,
@@ -122,6 +127,53 @@ export async function getDefaultBranch(
   })
 }
 
+export async function tryGetRepositoryObjectFormat(
+  authToken: string,
+  owner: string,
+  repo: string,
+  baseUrl?: string,
+  commit?: string
+): Promise<RepositoryObjectFormatResult> {
+  const commitFormat = getObjectFormat(commit)
+  if (commitFormat) {
+    return {format: commitFormat, succeeded: true}
+  }
+
+  try {
+    const octokit = github.getOctokit(authToken, {
+      baseUrl: getServerApiUrl(baseUrl)
+    })
+    const response = await octokit.request(
+      'GET /repos/{owner}/{repo}/hash-algorithm',
+      {owner, repo}
+    )
+    const hashAlgorithm = response.data.hash_algorithm
+    if (hashAlgorithm === 'sha256' || hashAlgorithm === 'sha1') {
+      return {format: hashAlgorithm, succeeded: true}
+    }
+
+    core.debug(
+      'Unable to determine repository object format from hash-algorithm endpoint'
+    )
+    return {format: '', succeeded: false}
+  } catch (err) {
+    core.debug(
+      `Unable to determine repository object format from hash-algorithm endpoint: ${(err as any)?.message ?? err}`
+    )
+    return {format: '', succeeded: false}
+  }
+}
+
+function getObjectFormat(sha?: string): string {
+  if (/^[0-9a-fA-F]{64}$/.test(sha || '')) {
+    return 'sha256'
+  }
+  if (/^[0-9a-fA-F]{40}$/.test(sha || '')) {
+    return 'sha1'
+  }
+  return ''
+}
+
 async function downloadArchive(
   authToken: string,
   owner: string,

src/input-helper.ts

@@ -89,7 +89,7 @@ export async function getInputs(): Promise<IGitSourceSettings> {
     }
   }
   // SHA?
-  else if (asciiTrimmedRef.match(/^[0-9a-fA-F]{40}$/)) {
+  else if (asciiTrimmedRef.match(/^(?:[0-9a-fA-F]{40}|[0-9a-fA-F]{64})$/)) {
     result.commit = asciiTrimmedRef
     result.ref = ''
   }

src/misc/generate-docs.ts

@@ -120,7 +120,7 @@ function updateUsage(
 }
 
 updateUsage(
-  'actions/checkout@v5',
+  'actions/checkout@v6',
   path.join(__dirname, '..', '..', 'action.yml'),
   path.join(__dirname, '..', '..', 'README.md')
 )

src/ref-helper.ts

@@ -76,55 +76,75 @@ export function getRefSpecForAllHistory(ref: string, commit: string): string[] {
   return result
 }
 
-export function getRefSpec(ref: string, commit: string): string[] {
+export function getRefSpec(
+  ref: string,
+  commit: string,
+  fetchTags?: boolean
+): string[] {
   if (!ref && !commit) {
     throw new Error('Args ref and commit cannot both be empty')
   }
 
   const upperRef = (ref || '').toUpperCase()
+  const result: string[] = []
+
+  // When fetchTags is true, always include the tags refspec
+  if (fetchTags) {
+    result.push(tagsRefSpec)
+  }
 
   // SHA
   if (commit) {
     // refs/heads
     if (upperRef.startsWith('REFS/HEADS/')) {
       const branch = ref.substring('refs/heads/'.length)
-      return [`+${commit}:refs/remotes/origin/${branch}`]
+      result.push(`+${commit}:refs/remotes/origin/${branch}`)
     }
     // refs/pull/
     else if (upperRef.startsWith('REFS/PULL/')) {
       const branch = ref.substring('refs/pull/'.length)
-      return [`+${commit}:refs/remotes/pull/${branch}`]
+      result.push(`+${commit}:refs/remotes/pull/${branch}`)
     }
     // refs/tags/
     else if (upperRef.startsWith('REFS/TAGS/')) {
-      return [`+${commit}:${ref}`]
+      if (!fetchTags) {
+        result.push(`+${ref}:${ref}`)
+      }
     }
     // Otherwise no destination ref
     else {
-      return [commit]
+      result.push(commit)
     }
   }
   // Unqualified ref, check for a matching branch or tag
   else if (!upperRef.startsWith('REFS/')) {
-    return [
-      `+refs/heads/${ref}*:refs/remotes/origin/${ref}*`,
-      `+refs/tags/${ref}*:refs/tags/${ref}*`
-    ]
+    result.push(`+refs/heads/${ref}*:refs/remotes/origin/${ref}*`)
+    if (!fetchTags) {
+      result.push(`+refs/tags/${ref}*:refs/tags/${ref}*`)
+    }
   }
   // refs/heads/
   else if (upperRef.startsWith('REFS/HEADS/')) {
     const branch = ref.substring('refs/heads/'.length)
-    return [`+${ref}:refs/remotes/origin/${branch}`]
+    result.push(`+${ref}:refs/remotes/origin/${branch}`)
   }
   // refs/pull/
   else if (upperRef.startsWith('REFS/PULL/')) {
     const branch = ref.substring('refs/pull/'.length)
-    return [`+${ref}:refs/remotes/pull/${branch}`]
+    result.push(`+${ref}:refs/remotes/pull/${branch}`)
   }
   // refs/tags/
-  else {
-    return [`+${ref}:${ref}`]
+  else if (upperRef.startsWith('REFS/TAGS/')) {
+    if (!fetchTags) {
+      result.push(`+${ref}:${ref}`)
+    }
   }
+  // Other refs
+  else {
+    result.push(`+${ref}:${ref}`)
+  }
+
+  return result
 }
 
 /**
@@ -170,8 +190,10 @@ export async function testRef(
   // refs/tags/
   else if (upperRef.startsWith('REFS/TAGS/')) {
     const tagName = ref.substring('refs/tags/'.length)
+    // Use ^{commit} to dereference annotated tags to their underlying commit
     return (
-      (await git.tagExists(tagName)) && commit === (await git.revParse(ref))
+      (await git.tagExists(tagName)) &&
+      commit === (await git.revParse(`${ref}^{commit}`))
     )
   }
   // Unexpected
@@ -236,7 +258,9 @@ export async function checkCommitInfo(
     }
 
     // Extract details from message
-    const match = commitInfo.match(/Merge ([0-9a-f]{40}) into ([0-9a-f]{40})/)
+    const match = commitInfo.match(
+      /Merge ([0-9a-f]{40}|[0-9a-f]{64}) into ([0-9a-f]{40}|[0-9a-f]{64})/
+    )
     if (!match) {
       core.debug('Unexpected message format')
       return