improve description for fetch-depth (#301)

* persist core.sshCommand for submodules

* update verbiage; add comments

* fail when submodules or ssh-key and fallback to REST API

.github/workflows/test.yml

@@ -11,13 +11,14 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
+      - uses: actions/setup-node@v1
+        with:
+          node-version: 12.x
       - uses: actions/checkout@v2
       - run: npm ci
       - run: npm run build
       - run: npm run format-check
       - run: npm run lint
-      - run: npm run pack
-      - run: npm run gendocs
       - run: npm test
       - name: Verify no unstaged changes
         run: __test__/verify-no-unstaged-changes.sh
@@ -34,7 +35,7 @@ jobs:
         uses: actions/checkout@v2
 
       # Basic checkout
-      - name: Basic checkout
+      - name: Checkout basic
         uses: ./
         with:
           ref: test-data/v2/basic
@@ -47,7 +48,7 @@ jobs:
       - name: Modify work tree
         shell: bash
         run: __test__/modify-work-tree.sh
-      - name: Clean checkout
+      - name: Checkout clean
         uses: ./
         with:
           ref: test-data/v2/basic
@@ -57,12 +58,12 @@ jobs:
         run: __test__/verify-clean.sh
 
       # Side by side
-      - name: Side by side checkout 1
+      - name: Checkout side by side 1
         uses: ./
         with:
           ref: test-data/v2/side-by-side-1
           path: side-by-side-1
-      - name: Side by side checkout 2
+      - name: Checkout side by side 2
         uses: ./
         with:
           ref: test-data/v2/side-by-side-2
@@ -72,7 +73,7 @@ jobs:
         run: __test__/verify-side-by-side.sh
 
       # LFS
-      - name: LFS checkout
+      - name: Checkout LFS
         uses: ./
         with:
           repository: actions/checkout # hardcoded, otherwise doesn't work from a fork
@@ -83,16 +84,121 @@ jobs:
         shell: bash
         run: __test__/verify-lfs.sh
 
-  test-job-container:
+      # Submodules false
-    runs-on: ubuntu-latest
+      - name: Checkout submodules false
-    container: alpine:latest
+        uses: ./
-    steps:
+        with:
-      # Clone this repo
+          ref: test-data/v2/submodule-ssh-url
-      - name: Checkout
+          path: submodules-false
-        uses: actions/checkout@v2
+      - name: Verify submodules false
+        run: __test__/verify-submodules-false.sh
 
-      # Basic checkout
+      # Submodules one level
-      - name: Basic checkout
+      - name: Checkout submodules true
+        uses: ./
+        with:
+          ref: test-data/v2/submodule-ssh-url
+          path: submodules-true
+          submodules: true
+      - name: Verify submodules true
+        run: __test__/verify-submodules-true.sh
+
+      # Submodules recursive
+      - name: Checkout submodules recursive
+        uses: ./
+        with:
+          ref: test-data/v2/submodule-ssh-url
+          path: submodules-recursive
+          submodules: recursive
+      - name: Verify submodules recursive
+        run: __test__/verify-submodules-recursive.sh
+
+      # Basic checkout using REST API
+      - name: Remove basic
+        if: runner.os != 'windows'
+        run: rm -rf basic
+      - name: Remove basic (Windows)
+        if: runner.os == 'windows'
+        shell: cmd
+        run: rmdir /s /q basic
+      - name: Override git version
+        if: runner.os != 'windows'
+        run: __test__/override-git-version.sh
+      - name: Override git version (Windows)
+        if: runner.os == 'windows'
+        run: __test__\\override-git-version.cmd
+      - name: Checkout basic using REST API
+        uses: ./
+        with:
+          ref: test-data/v2/basic
+          path: basic
+      - name: Verify basic
+        run: __test__/verify-basic.sh --archive
+
+  test-proxy:
+    runs-on: ubuntu-latest
+    container:
+      image: alpine/git:latest
+      options: --dns 127.0.0.1
+    services:
+      squid-proxy:
+        image: datadog/squid:latest
+        ports:
+          - 3128:3128
+    env:
+      https_proxy: http://squid-proxy:3128
+    steps:
+      # Clone this repo
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      # Basic checkout using git
+      - name: Checkout basic
+        uses: ./
+        with:
+          ref: test-data/v2/basic
+          path: basic
+      - name: Verify basic
+        run: __test__/verify-basic.sh
+
+      # Basic checkout using REST API
+      - name: Remove basic
+        run: rm -rf basic
+      - name: Override git version
+        run: __test__/override-git-version.sh
+      - name: Basic checkout using REST API
+        uses: ./
+        with:
+          ref: test-data/v2/basic
+          path: basic
+      - name: Verify basic
+        run: __test__/verify-basic.sh --archive
+
+  test-bypass-proxy:
+    runs-on: ubuntu-latest
+    env:
+      https_proxy: http://no-such-proxy:3128
+      no_proxy: api.github.com,github.com
+    steps:
+      # Clone this repo
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      # Basic checkout using git
+      - name: Checkout basic
+        uses: ./
+        with:
+          ref: test-data/v2/basic
+          path: basic
+      - name: Verify basic
+        run: __test__/verify-basic.sh
+      - name: Remove basic
+        run: rm -rf basic
+
+      # Basic checkout using REST API
+      - name: Override git version
+        run: __test__/override-git-version.sh
+      - name: Checkout basic using REST API
         uses: ./
         with:
           ref: test-data/v2/basic

.gitignore

@@ -1,2 +1,3 @@
+__test__/_temp
 lib/
 node_modules/

CHANGELOG.md

@@ -1,5 +1,40 @@
 # Changelog
 
+## v2.3.1
+
+- [Fix default branch resolution for .wiki and when using SSH](https://github.com/actions/checkout/pull/284)
+
+
+## v2.3.0
+
+- [Fallback to the default branch](https://github.com/actions/checkout/pull/278)
+
+## v2.2.0
+
+- [Fetch all history for all tags and branches when fetch-depth=0](https://github.com/actions/checkout/pull/258)
+
+## v2.1.1
+
+- Changes to support GHES ([here](https://github.com/actions/checkout/pull/236) and [here](https://github.com/actions/checkout/pull/248))
+
+## v2.1.0
+
+- [Group output](https://github.com/actions/checkout/pull/191)
+- [Changes to support GHES alpha release](https://github.com/actions/checkout/pull/199)
+- [Persist core.sshCommand for submodules](https://github.com/actions/checkout/pull/184)
+- [Add support ssh](https://github.com/actions/checkout/pull/163)
+- [Convert submodule SSH URL to HTTPS, when not using SSH](https://github.com/actions/checkout/pull/179)
+- [Add submodule support](https://github.com/actions/checkout/pull/157)
+- [Follow proxy settings](https://github.com/actions/checkout/pull/144)
+- [Fix ref for pr closed event when a pr is merged](https://github.com/actions/checkout/pull/141)
+- [Fix issue checking detached when git less than 2.22](https://github.com/actions/checkout/pull/128)
+
+## v2.0.0
+
+- [Do not pass cred on command line](https://github.com/actions/checkout/pull/108)
+- [Add input persist-credentials](https://github.com/actions/checkout/pull/107)
+- [Fallback to REST API to download repo](https://github.com/actions/checkout/pull/104)
+
 ## v2 (beta)
 
 - Improved fetch performance

README.md

@@ -6,7 +6,7 @@
 
 This action checks-out your repository under `$GITHUB_WORKSPACE`, so your workflow can access it.
 
-Only a single commit is fetched by default, for the ref/SHA that triggered the workflow. Set `fetch-depth` to fetch more history. Refer [here](https://help.github.com/en/articles/events-that-trigger-workflows) to learn which commit `$GITHUB_SHA` points to for different events.
+Only a single commit is fetched by default, for the ref/SHA that triggered the workflow. Set `fetch-depth: 0` to fetch all history for all branches and tags. Refer [here](https://help.github.com/en/articles/events-that-trigger-workflows) to learn which commit `$GITHUB_SHA` points to for different events.
 
 The auth token is persisted in the local git config. This enables your scripts to run authenticated git commands. The token is removed during post-job cleanup. Set `persist-credentials: false` to opt-out.
 
@@ -18,6 +18,7 @@ When Git 2.18 or higher is not in your PATH, falls back to the REST API to downl
   - Fetches only a single commit by default
 - Script authenticated git commands
   - Auth token persisted in the local git config
+- Supports SSH
 - Creates a local branch
   - No longer detached HEAD when checking out a branch
 - Improved layout
@@ -26,7 +27,6 @@ When Git 2.18 or higher is not in your PATH, falls back to the REST API to downl
 - Fallback to REST API download
   - When Git 2.18 or higher is not in the PATH, the REST API will be used to download the files
   - When using a job container, the container's PATH is used
-- Removed input `submodules`
 
 Refer [here](https://github.com/actions/checkout/blob/v1/README.md) for previous versions.
 
@@ -42,17 +42,43 @@ Refer [here](https://github.com/actions/checkout/blob/v1/README.md) for previous
 
     # The branch, tag or SHA to checkout. When checking out the repository that
     # triggered a workflow, this defaults to the reference or SHA for that event.
-    # Otherwise, defaults to `master`.
+    # Otherwise, uses the default branch.
     ref: ''
 
-    # Auth token used to fetch the repository. The token is stored in the local git
+    # Personal access token (PAT) used to fetch the repository. The PAT is configured
-    # config, which enables your scripts to run authenticated git commands. The
+    # with the local git config, which enables your scripts to run authenticated git
-    # post-job step removes the token from the git config. [Learn more about creating
+    # commands. The post-job step removes the PAT.
-    # and using encrypted secrets](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/creating-and-using-encrypted-secrets)
+    #
+    # We recommend using a service account with the least permissions necessary. Also
+    # when generating a new PAT, select the least scopes necessary.
+    #
+    # [Learn more about creating and using encrypted secrets](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/creating-and-using-encrypted-secrets)
+    #
     # Default: ${{ github.token }}
     token: ''
 
-    # Whether to persist the token in the git config
+    # SSH key used to fetch the repository. The SSH key is configured with the local
+    # git config, which enables your scripts to run authenticated git commands. The
+    # post-job step removes the SSH key.
+    #
+    # We recommend using a service account with the least permissions necessary.
+    #
+    # [Learn more about creating and using encrypted secrets](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/creating-and-using-encrypted-secrets)
+    ssh-key: ''
+
+    # Known hosts in addition to the user and global host key database. The public SSH
+    # keys for a host may be obtained using the utility `ssh-keyscan`. For example,
+    # `ssh-keyscan github.com`. The public key for github.com is always implicitly
+    # added.
+    ssh-known-hosts: ''
+
+    # Whether to perform strict host key checking. When true, adds the options
+    # `StrictHostKeyChecking=yes` and `CheckHostIP=no` to the SSH command line. Use
+    # the input `ssh-known-hosts` to configure additional hosts.
+    # Default: true
+    ssh-strict: ''
+
+    # Whether to configure the token or SSH key with the local git config
     # Default: true
     persist-credentials: ''
 
@@ -63,18 +89,28 @@ Refer [here](https://github.com/actions/checkout/blob/v1/README.md) for previous
     # Default: true
     clean: ''
 
-    # Number of commits to fetch. 0 indicates all history.
+    # Number of commits to fetch. 0 indicates all history for all branches and tags.
     # Default: 1
     fetch-depth: ''
 
     # Whether to download Git-LFS files
     # Default: false
     lfs: ''
+
+    # Whether to checkout submodules: `true` to checkout submodules or `recursive` to
+    # recursively checkout submodules.
+    #
+    # When the `ssh-key` input is not provided, SSH URLs beginning with
+    # `git@github.com:` are converted to HTTPS.
+    #
+    # Default: false
+    submodules: ''
 ```
 <!-- end usage -->
 
 # Scenarios
 
+- [Fetch all history for all tags and branches](#Fetch-all-history-for-all-tags-and-branches)
 - [Checkout a different branch](#Checkout-a-different-branch)
 - [Checkout HEAD^](#Checkout-HEAD)
 - [Checkout multiple repos (side by side)](#Checkout-multiple-repos-side-by-side)
@@ -82,10 +118,14 @@ Refer [here](https://github.com/actions/checkout/blob/v1/README.md) for previous
 - [Checkout multiple repos (private)](#Checkout-multiple-repos-private)
 - [Checkout pull request HEAD commit instead of merge commit](#Checkout-pull-request-HEAD-commit-instead-of-merge-commit)
 - [Checkout pull request on closed event](#Checkout-pull-request-on-closed-event)
-- [Checkout submodules](#Checkout-submodules)
+
-- [Fetch all tags](#Fetch-all-tags)
+## Fetch all history for all tags and branches
-- [Fetch all branches](#Fetch-all-branches)
+
-- [Fetch all history for all tags and branches](#Fetch-all-history-for-all-tags-and-branches)
+```yaml
+- uses: actions/checkout@v2
+  with:
+    fetch-depth: 0
+```
 
 ## Checkout a different branch
 
@@ -173,41 +213,6 @@ jobs:
       - uses: actions/checkout@v2
 ```
 
-## Checkout submodules
-
-```yaml
-- uses: actions/checkout@v2
-- name: Checkout submodules
-  shell: bash
-  run: |
-    auth_header="$(git config --local --get http.https://github.com/.extraheader)"
-    git submodule sync --recursive
-    git -c "http.extraheader=$auth_header" -c protocol.version=2 submodule update --init --force --recursive --depth=1
-```
-
-## Fetch all tags
-
-```yaml
-- uses: actions/checkout@v2
-- run: git fetch --depth=1 origin +refs/tags/*:refs/tags/*
-```
-
-## Fetch all branches
-
-```yaml
-- uses: actions/checkout@v2
-- run: |
-    git fetch --no-tags --prune --depth=1 origin +refs/heads/*:refs/remotes/origin/*
-```
-
-## Fetch all history for all tags and branches
-
-```yaml
-- uses: actions/checkout@v2
-- run: |
-    git fetch --prune --unshallow
-```
-
 # License
 
 The scripts and documentation in this project are released under the [MIT License](LICENSE)

__test__/git-auth-helper.test.ts

@@ -0,0 +1,802 @@
+import * as core from '@actions/core'
+import * as fs from 'fs'
+import * as gitAuthHelper from '../lib/git-auth-helper'
+import * as io from '@actions/io'
+import * as os from 'os'
+import * as path from 'path'
+import * as stateHelper from '../lib/state-helper'
+import {IGitCommandManager} from '../lib/git-command-manager'
+import {IGitSourceSettings} from '../lib/git-source-settings'
+
+const isWindows = process.platform === 'win32'
+const testWorkspace = path.join(__dirname, '_temp', 'git-auth-helper')
+const originalRunnerTemp = process.env['RUNNER_TEMP']
+const originalHome = process.env['HOME']
+let workspace: string
+let localGitConfigPath: string
+let globalGitConfigPath: string
+let runnerTemp: string
+let tempHomedir: string
+let git: IGitCommandManager & {env: {[key: string]: string}}
+let settings: IGitSourceSettings
+let sshPath: string
+
+describe('git-auth-helper tests', () => {
+  beforeAll(async () => {
+    // SSH
+    sshPath = await io.which('ssh')
+
+    // Clear test workspace
+    await io.rmRF(testWorkspace)
+  })
+
+  beforeEach(() => {
+    // Mock setSecret
+    jest.spyOn(core, 'setSecret').mockImplementation((secret: string) => {})
+
+    // Mock error/warning/info/debug
+    jest.spyOn(core, 'error').mockImplementation(jest.fn())
+    jest.spyOn(core, 'warning').mockImplementation(jest.fn())
+    jest.spyOn(core, 'info').mockImplementation(jest.fn())
+    jest.spyOn(core, 'debug').mockImplementation(jest.fn())
+
+    // Mock state helper
+    jest.spyOn(stateHelper, 'setSshKeyPath').mockImplementation(jest.fn())
+    jest
+      .spyOn(stateHelper, 'setSshKnownHostsPath')
+      .mockImplementation(jest.fn())
+  })
+
+  afterEach(() => {
+    // Unregister mocks
+    jest.restoreAllMocks()
+
+    // Restore HOME
+    if (originalHome) {
+      process.env['HOME'] = originalHome
+    } else {
+      delete process.env['HOME']
+    }
+  })
+
+  afterAll(() => {
+    // Restore RUNNER_TEMP
+    delete process.env['RUNNER_TEMP']
+    if (originalRunnerTemp) {
+      process.env['RUNNER_TEMP'] = originalRunnerTemp
+    }
+  })
+
+  const configureAuth_configuresAuthHeader =
+    'configureAuth configures auth header'
+  it(configureAuth_configuresAuthHeader, async () => {
+    // Arrange
+    await setup(configureAuth_configuresAuthHeader)
+    expect(settings.authToken).toBeTruthy() // sanity check
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+
+    // Act
+    await authHelper.configureAuth()
+
+    // Assert config
+    const configContent = (
+      await fs.promises.readFile(localGitConfigPath)
+    ).toString()
+    const basicCredential = Buffer.from(
+      `x-access-token:${settings.authToken}`,
+      'utf8'
+    ).toString('base64')
+    expect(
+      configContent.indexOf(
+        `http.https://github.com/.extraheader AUTHORIZATION: basic ${basicCredential}`
+      )
+    ).toBeGreaterThanOrEqual(0)
+  })
+
+  const configureAuth_configuresAuthHeaderEvenWhenPersistCredentialsFalse =
+    'configureAuth configures auth header even when persist credentials false'
+  it(
+    configureAuth_configuresAuthHeaderEvenWhenPersistCredentialsFalse,
+    async () => {
+      // Arrange
+      await setup(
+        configureAuth_configuresAuthHeaderEvenWhenPersistCredentialsFalse
+      )
+      expect(settings.authToken).toBeTruthy() // sanity check
+      settings.persistCredentials = false
+      const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+
+      // Act
+      await authHelper.configureAuth()
+
+      // Assert config
+      const configContent = (
+        await fs.promises.readFile(localGitConfigPath)
+      ).toString()
+      expect(
+        configContent.indexOf(
+          `http.https://github.com/.extraheader AUTHORIZATION`
+        )
+      ).toBeGreaterThanOrEqual(0)
+    }
+  )
+
+  const configureAuth_copiesUserKnownHosts =
+    'configureAuth copies user known hosts'
+  it(configureAuth_copiesUserKnownHosts, async () => {
+    if (!sshPath) {
+      process.stdout.write(
+        `Skipped test "${configureAuth_copiesUserKnownHosts}". Executable 'ssh' not found in the PATH.\n`
+      )
+      return
+    }
+
+    // Arange
+    await setup(configureAuth_copiesUserKnownHosts)
+    expect(settings.sshKey).toBeTruthy() // sanity check
+
+    // Mock fs.promises.readFile
+    const realReadFile = fs.promises.readFile
+    jest.spyOn(fs.promises, 'readFile').mockImplementation(
+      async (file: any, options: any): Promise<Buffer> => {
+        const userKnownHostsPath = path.join(
+          os.homedir(),
+          '.ssh',
+          'known_hosts'
+        )
+        if (file === userKnownHostsPath) {
+          return Buffer.from('some-domain.com ssh-rsa ABCDEF')
+        }
+
+        return await realReadFile(file, options)
+      }
+    )
+
+    // Act
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+    await authHelper.configureAuth()
+
+    // Assert known hosts
+    const actualSshKnownHostsPath = await getActualSshKnownHostsPath()
+    const actualSshKnownHostsContent = (
+      await fs.promises.readFile(actualSshKnownHostsPath)
+    ).toString()
+    expect(actualSshKnownHostsContent).toMatch(
+      /some-domain\.com ssh-rsa ABCDEF/
+    )
+    expect(actualSshKnownHostsContent).toMatch(/github\.com ssh-rsa AAAAB3N/)
+  })
+
+  const configureAuth_registersBasicCredentialAsSecret =
+    'configureAuth registers basic credential as secret'
+  it(configureAuth_registersBasicCredentialAsSecret, async () => {
+    // Arrange
+    await setup(configureAuth_registersBasicCredentialAsSecret)
+    expect(settings.authToken).toBeTruthy() // sanity check
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+
+    // Act
+    await authHelper.configureAuth()
+
+    // Assert secret
+    const setSecretSpy = core.setSecret as jest.Mock<any, any>
+    expect(setSecretSpy).toHaveBeenCalledTimes(1)
+    const expectedSecret = Buffer.from(
+      `x-access-token:${settings.authToken}`,
+      'utf8'
+    ).toString('base64')
+    expect(setSecretSpy).toHaveBeenCalledWith(expectedSecret)
+  })
+
+  const setsSshCommandEnvVarWhenPersistCredentialsFalse =
+    'sets SSH command env var when persist-credentials false'
+  it(setsSshCommandEnvVarWhenPersistCredentialsFalse, async () => {
+    if (!sshPath) {
+      process.stdout.write(
+        `Skipped test "${setsSshCommandEnvVarWhenPersistCredentialsFalse}". Executable 'ssh' not found in the PATH.\n`
+      )
+      return
+    }
+
+    // Arrange
+    await setup(setsSshCommandEnvVarWhenPersistCredentialsFalse)
+    settings.persistCredentials = false
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+
+    // Act
+    await authHelper.configureAuth()
+
+    // Assert git env var
+    const actualKeyPath = await getActualSshKeyPath()
+    const actualKnownHostsPath = await getActualSshKnownHostsPath()
+    const expectedSshCommand = `"${sshPath}" -i "$RUNNER_TEMP/${path.basename(
+      actualKeyPath
+    )}" -o StrictHostKeyChecking=yes -o CheckHostIP=no -o "UserKnownHostsFile=$RUNNER_TEMP/${path.basename(
+      actualKnownHostsPath
+    )}"`
+    expect(git.setEnvironmentVariable).toHaveBeenCalledWith(
+      'GIT_SSH_COMMAND',
+      expectedSshCommand
+    )
+
+    // Asserty git config
+    const gitConfigLines = (await fs.promises.readFile(localGitConfigPath))
+      .toString()
+      .split('\n')
+      .filter(x => x)
+    expect(gitConfigLines).toHaveLength(1)
+    expect(gitConfigLines[0]).toMatch(/^http\./)
+  })
+
+  const configureAuth_setsSshCommandWhenPersistCredentialsTrue =
+    'sets SSH command when persist-credentials true'
+  it(configureAuth_setsSshCommandWhenPersistCredentialsTrue, async () => {
+    if (!sshPath) {
+      process.stdout.write(
+        `Skipped test "${configureAuth_setsSshCommandWhenPersistCredentialsTrue}". Executable 'ssh' not found in the PATH.\n`
+      )
+      return
+    }
+
+    // Arrange
+    await setup(configureAuth_setsSshCommandWhenPersistCredentialsTrue)
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+
+    // Act
+    await authHelper.configureAuth()
+
+    // Assert git env var
+    const actualKeyPath = await getActualSshKeyPath()
+    const actualKnownHostsPath = await getActualSshKnownHostsPath()
+    const expectedSshCommand = `"${sshPath}" -i "$RUNNER_TEMP/${path.basename(
+      actualKeyPath
+    )}" -o StrictHostKeyChecking=yes -o CheckHostIP=no -o "UserKnownHostsFile=$RUNNER_TEMP/${path.basename(
+      actualKnownHostsPath
+    )}"`
+    expect(git.setEnvironmentVariable).toHaveBeenCalledWith(
+      'GIT_SSH_COMMAND',
+      expectedSshCommand
+    )
+
+    // Asserty git config
+    expect(git.config).toHaveBeenCalledWith(
+      'core.sshCommand',
+      expectedSshCommand
+    )
+  })
+
+  const configureAuth_writesExplicitKnownHosts = 'writes explicit known hosts'
+  it(configureAuth_writesExplicitKnownHosts, async () => {
+    if (!sshPath) {
+      process.stdout.write(
+        `Skipped test "${configureAuth_writesExplicitKnownHosts}". Executable 'ssh' not found in the PATH.\n`
+      )
+      return
+    }
+
+    // Arrange
+    await setup(configureAuth_writesExplicitKnownHosts)
+    expect(settings.sshKey).toBeTruthy() // sanity check
+    settings.sshKnownHosts = 'my-custom-host.com ssh-rsa ABC123'
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+
+    // Act
+    await authHelper.configureAuth()
+
+    // Assert known hosts
+    const actualSshKnownHostsPath = await getActualSshKnownHostsPath()
+    const actualSshKnownHostsContent = (
+      await fs.promises.readFile(actualSshKnownHostsPath)
+    ).toString()
+    expect(actualSshKnownHostsContent).toMatch(
+      /my-custom-host\.com ssh-rsa ABC123/
+    )
+    expect(actualSshKnownHostsContent).toMatch(/github\.com ssh-rsa AAAAB3N/)
+  })
+
+  const configureAuth_writesSshKeyAndImplicitKnownHosts =
+    'writes SSH key and implicit known hosts'
+  it(configureAuth_writesSshKeyAndImplicitKnownHosts, async () => {
+    if (!sshPath) {
+      process.stdout.write(
+        `Skipped test "${configureAuth_writesSshKeyAndImplicitKnownHosts}". Executable 'ssh' not found in the PATH.\n`
+      )
+      return
+    }
+
+    // Arrange
+    await setup(configureAuth_writesSshKeyAndImplicitKnownHosts)
+    expect(settings.sshKey).toBeTruthy() // sanity check
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+
+    // Act
+    await authHelper.configureAuth()
+
+    // Assert SSH key
+    const actualSshKeyPath = await getActualSshKeyPath()
+    expect(actualSshKeyPath).toBeTruthy()
+    const actualSshKeyContent = (
+      await fs.promises.readFile(actualSshKeyPath)
+    ).toString()
+    expect(actualSshKeyContent).toBe(settings.sshKey + '\n')
+    if (!isWindows) {
+      // Assert read/write for user, not group or others.
+      // Otherwise SSH client will error.
+      expect((await fs.promises.stat(actualSshKeyPath)).mode & 0o777).toBe(
+        0o600
+      )
+    }
+
+    // Assert known hosts
+    const actualSshKnownHostsPath = await getActualSshKnownHostsPath()
+    const actualSshKnownHostsContent = (
+      await fs.promises.readFile(actualSshKnownHostsPath)
+    ).toString()
+    expect(actualSshKnownHostsContent).toMatch(/github\.com ssh-rsa AAAAB3N/)
+  })
+
+  const configureGlobalAuth_configuresUrlInsteadOfWhenSshKeyNotSet =
+    'configureGlobalAuth configures URL insteadOf when SSH key not set'
+  it(configureGlobalAuth_configuresUrlInsteadOfWhenSshKeyNotSet, async () => {
+    // Arrange
+    await setup(configureGlobalAuth_configuresUrlInsteadOfWhenSshKeyNotSet)
+    settings.sshKey = ''
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+
+    // Act
+    await authHelper.configureAuth()
+    await authHelper.configureGlobalAuth()
+
+    // Assert temporary global config
+    expect(git.env['HOME']).toBeTruthy()
+    const configContent = (
+      await fs.promises.readFile(path.join(git.env['HOME'], '.gitconfig'))
+    ).toString()
+    expect(
+      configContent.indexOf(`url.https://github.com/.insteadOf git@github.com`)
+    ).toBeGreaterThanOrEqual(0)
+  })
+
+  const configureGlobalAuth_copiesGlobalGitConfig =
+    'configureGlobalAuth copies global git config'
+  it(configureGlobalAuth_copiesGlobalGitConfig, async () => {
+    // Arrange
+    await setup(configureGlobalAuth_copiesGlobalGitConfig)
+    await fs.promises.writeFile(globalGitConfigPath, 'value-from-global-config')
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+
+    // Act
+    await authHelper.configureAuth()
+    await authHelper.configureGlobalAuth()
+
+    // Assert original global config not altered
+    let configContent = (
+      await fs.promises.readFile(globalGitConfigPath)
+    ).toString()
+    expect(configContent).toBe('value-from-global-config')
+
+    // Assert temporary global config
+    expect(git.env['HOME']).toBeTruthy()
+    const basicCredential = Buffer.from(
+      `x-access-token:${settings.authToken}`,
+      'utf8'
+    ).toString('base64')
+    configContent = (
+      await fs.promises.readFile(path.join(git.env['HOME'], '.gitconfig'))
+    ).toString()
+    expect(
+      configContent.indexOf('value-from-global-config')
+    ).toBeGreaterThanOrEqual(0)
+    expect(
+      configContent.indexOf(
+        `http.https://github.com/.extraheader AUTHORIZATION: basic ${basicCredential}`
+      )
+    ).toBeGreaterThanOrEqual(0)
+  })
+
+  const configureGlobalAuth_createsNewGlobalGitConfigWhenGlobalDoesNotExist =
+    'configureGlobalAuth creates new git config when global does not exist'
+  it(
+    configureGlobalAuth_createsNewGlobalGitConfigWhenGlobalDoesNotExist,
+    async () => {
+      // Arrange
+      await setup(
+        configureGlobalAuth_createsNewGlobalGitConfigWhenGlobalDoesNotExist
+      )
+      await io.rmRF(globalGitConfigPath)
+      const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+
+      // Act
+      await authHelper.configureAuth()
+      await authHelper.configureGlobalAuth()
+
+      // Assert original global config not recreated
+      try {
+        await fs.promises.stat(globalGitConfigPath)
+        throw new Error(
+          `Did not expect file to exist: '${globalGitConfigPath}'`
+        )
+      } catch (err) {
+        if (err.code !== 'ENOENT') {
+          throw err
+        }
+      }
+
+      // Assert temporary global config
+      expect(git.env['HOME']).toBeTruthy()
+      const basicCredential = Buffer.from(
+        `x-access-token:${settings.authToken}`,
+        'utf8'
+      ).toString('base64')
+      const configContent = (
+        await fs.promises.readFile(path.join(git.env['HOME'], '.gitconfig'))
+      ).toString()
+      expect(
+        configContent.indexOf(
+          `http.https://github.com/.extraheader AUTHORIZATION: basic ${basicCredential}`
+        )
+      ).toBeGreaterThanOrEqual(0)
+    }
+  )
+
+  const configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsFalseAndSshKeyNotSet =
+    'configureSubmoduleAuth configures submodules when persist credentials false and SSH key not set'
+  it(
+    configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsFalseAndSshKeyNotSet,
+    async () => {
+      // Arrange
+      await setup(
+        configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsFalseAndSshKeyNotSet
+      )
+      settings.persistCredentials = false
+      settings.sshKey = ''
+      const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+      await authHelper.configureAuth()
+      const mockSubmoduleForeach = git.submoduleForeach as jest.Mock<any, any>
+      mockSubmoduleForeach.mockClear() // reset calls
+
+      // Act
+      await authHelper.configureSubmoduleAuth()
+
+      // Assert
+      expect(mockSubmoduleForeach).toBeCalledTimes(1)
+      expect(mockSubmoduleForeach.mock.calls[0][0] as string).toMatch(
+        /unset-all.*insteadOf/
+      )
+    }
+  )
+
+  const configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsFalseAndSshKeySet =
+    'configureSubmoduleAuth configures submodules when persist credentials false and SSH key set'
+  it(
+    configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsFalseAndSshKeySet,
+    async () => {
+      if (!sshPath) {
+        process.stdout.write(
+          `Skipped test "${configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsFalseAndSshKeySet}". Executable 'ssh' not found in the PATH.\n`
+        )
+        return
+      }
+
+      // Arrange
+      await setup(
+        configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsFalseAndSshKeySet
+      )
+      settings.persistCredentials = false
+      const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+      await authHelper.configureAuth()
+      const mockSubmoduleForeach = git.submoduleForeach as jest.Mock<any, any>
+      mockSubmoduleForeach.mockClear() // reset calls
+
+      // Act
+      await authHelper.configureSubmoduleAuth()
+
+      // Assert
+      expect(mockSubmoduleForeach).toHaveBeenCalledTimes(1)
+      expect(mockSubmoduleForeach.mock.calls[0][0]).toMatch(
+        /unset-all.*insteadOf/
+      )
+    }
+  )
+
+  const configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsTrueAndSshKeyNotSet =
+    'configureSubmoduleAuth configures submodules when persist credentials true and SSH key not set'
+  it(
+    configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsTrueAndSshKeyNotSet,
+    async () => {
+      // Arrange
+      await setup(
+        configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsTrueAndSshKeyNotSet
+      )
+      settings.sshKey = ''
+      const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+      await authHelper.configureAuth()
+      const mockSubmoduleForeach = git.submoduleForeach as jest.Mock<any, any>
+      mockSubmoduleForeach.mockClear() // reset calls
+
+      // Act
+      await authHelper.configureSubmoduleAuth()
+
+      // Assert
+      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[2][0]).toMatch(/url.*insteadOf/)
+    }
+  )
+
+  const configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsTrueAndSshKeySet =
+    'configureSubmoduleAuth configures submodules when persist credentials true and SSH key set'
+  it(
+    configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsTrueAndSshKeySet,
+    async () => {
+      if (!sshPath) {
+        process.stdout.write(
+          `Skipped test "${configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsTrueAndSshKeySet}". Executable 'ssh' not found in the PATH.\n`
+        )
+        return
+      }
+
+      // Arrange
+      await setup(
+        configureSubmoduleAuth_configuresSubmodulesWhenPersistCredentialsTrueAndSshKeySet
+      )
+      const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+      await authHelper.configureAuth()
+      const mockSubmoduleForeach = git.submoduleForeach as jest.Mock<any, any>
+      mockSubmoduleForeach.mockClear() // reset calls
+
+      // Act
+      await authHelper.configureSubmoduleAuth()
+
+      // Assert
+      expect(mockSubmoduleForeach).toHaveBeenCalledTimes(3)
+      expect(mockSubmoduleForeach.mock.calls[0][0]).toMatch(
+        /unset-all.*insteadOf/
+      )
+      expect(mockSubmoduleForeach.mock.calls[1][0]).toMatch(/http.*extraheader/)
+      expect(mockSubmoduleForeach.mock.calls[2][0]).toMatch(/core\.sshCommand/)
+    }
+  )
+
+  const removeAuth_removesSshCommand = 'removeAuth removes SSH command'
+  it(removeAuth_removesSshCommand, async () => {
+    if (!sshPath) {
+      process.stdout.write(
+        `Skipped test "${removeAuth_removesSshCommand}". Executable 'ssh' not found in the PATH.\n`
+      )
+      return
+    }
+
+    // Arrange
+    await setup(removeAuth_removesSshCommand)
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+    await authHelper.configureAuth()
+    let gitConfigContent = (
+      await fs.promises.readFile(localGitConfigPath)
+    ).toString()
+    expect(gitConfigContent.indexOf('core.sshCommand')).toBeGreaterThanOrEqual(
+      0
+    ) // sanity check
+    const actualKeyPath = await getActualSshKeyPath()
+    expect(actualKeyPath).toBeTruthy()
+    await fs.promises.stat(actualKeyPath)
+    const actualKnownHostsPath = await getActualSshKnownHostsPath()
+    expect(actualKnownHostsPath).toBeTruthy()
+    await fs.promises.stat(actualKnownHostsPath)
+
+    // Act
+    await authHelper.removeAuth()
+
+    // Assert git config
+    gitConfigContent = (
+      await fs.promises.readFile(localGitConfigPath)
+    ).toString()
+    expect(gitConfigContent.indexOf('core.sshCommand')).toBeLessThan(0)
+
+    // Assert SSH key file
+    try {
+      await fs.promises.stat(actualKeyPath)
+      throw new Error('SSH key should have been deleted')
+    } catch (err) {
+      if (err.code !== 'ENOENT') {
+        throw err
+      }
+    }
+
+    // Assert known hosts file
+    try {
+      await fs.promises.stat(actualKnownHostsPath)
+      throw new Error('SSH known hosts should have been deleted')
+    } catch (err) {
+      if (err.code !== 'ENOENT') {
+        throw err
+      }
+    }
+  })
+
+  const removeAuth_removesToken = 'removeAuth removes token'
+  it(removeAuth_removesToken, async () => {
+    // Arrange
+    await setup(removeAuth_removesToken)
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+    await authHelper.configureAuth()
+    let gitConfigContent = (
+      await fs.promises.readFile(localGitConfigPath)
+    ).toString()
+    expect(gitConfigContent.indexOf('http.')).toBeGreaterThanOrEqual(0) // sanity check
+
+    // Act
+    await authHelper.removeAuth()
+
+    // Assert git config
+    gitConfigContent = (
+      await fs.promises.readFile(localGitConfigPath)
+    ).toString()
+    expect(gitConfigContent.indexOf('http.')).toBeLessThan(0)
+  })
+
+  const removeGlobalAuth_removesOverride = 'removeGlobalAuth removes override'
+  it(removeGlobalAuth_removesOverride, async () => {
+    // Arrange
+    await setup(removeGlobalAuth_removesOverride)
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+    await authHelper.configureAuth()
+    await authHelper.configureGlobalAuth()
+    const homeOverride = git.env['HOME'] // Sanity check
+    expect(homeOverride).toBeTruthy()
+    await fs.promises.stat(path.join(git.env['HOME'], '.gitconfig'))
+
+    // Act
+    await authHelper.removeGlobalAuth()
+
+    // Assert
+    expect(git.env['HOME']).toBeUndefined()
+    try {
+      await fs.promises.stat(homeOverride)
+      throw new Error(`Should have been deleted '${homeOverride}'`)
+    } catch (err) {
+      if (err.code !== 'ENOENT') {
+        throw err
+      }
+    }
+  })
+})
+
+async function setup(testName: string): Promise<void> {
+  testName = testName.replace(/[^a-zA-Z0-9_]+/g, '-')
+
+  // Directories
+  workspace = path.join(testWorkspace, testName, 'workspace')
+  runnerTemp = path.join(testWorkspace, testName, 'runner-temp')
+  tempHomedir = path.join(testWorkspace, testName, 'home-dir')
+  await fs.promises.mkdir(workspace, {recursive: true})
+  await fs.promises.mkdir(runnerTemp, {recursive: true})
+  await fs.promises.mkdir(tempHomedir, {recursive: true})
+  process.env['RUNNER_TEMP'] = runnerTemp
+  process.env['HOME'] = tempHomedir
+
+  // Create git config
+  globalGitConfigPath = path.join(tempHomedir, '.gitconfig')
+  await fs.promises.writeFile(globalGitConfigPath, '')
+  localGitConfigPath = path.join(workspace, '.git', 'config')
+  await fs.promises.mkdir(path.dirname(localGitConfigPath), {recursive: true})
+  await fs.promises.writeFile(localGitConfigPath, '')
+
+  git = {
+    branchDelete: jest.fn(),
+    branchExists: jest.fn(),
+    branchList: jest.fn(),
+    checkout: jest.fn(),
+    checkoutDetach: jest.fn(),
+    config: jest.fn(
+      async (key: string, value: string, globalConfig?: boolean) => {
+        const configPath = globalConfig
+          ? path.join(git.env['HOME'] || tempHomedir, '.gitconfig')
+          : localGitConfigPath
+        await fs.promises.appendFile(configPath, `\n${key} ${value}`)
+      }
+    ),
+    configExists: jest.fn(
+      async (key: string, globalConfig?: boolean): Promise<boolean> => {
+        const configPath = globalConfig
+          ? path.join(git.env['HOME'] || tempHomedir, '.gitconfig')
+          : localGitConfigPath
+        const content = await fs.promises.readFile(configPath)
+        const lines = content
+          .toString()
+          .split('\n')
+          .filter(x => x)
+        return lines.some(x => x.startsWith(key))
+      }
+    ),
+    env: {},
+    fetch: jest.fn(),
+    getDefaultBranch: jest.fn(),
+    getWorkingDirectory: jest.fn(() => workspace),
+    init: jest.fn(),
+    isDetached: jest.fn(),
+    lfsFetch: jest.fn(),
+    lfsInstall: jest.fn(),
+    log1: jest.fn(),
+    remoteAdd: jest.fn(),
+    removeEnvironmentVariable: jest.fn((name: string) => delete git.env[name]),
+    revParse: jest.fn(),
+    setEnvironmentVariable: jest.fn((name: string, value: string) => {
+      git.env[name] = value
+    }),
+    shaExists: jest.fn(),
+    submoduleForeach: jest.fn(async () => {
+      return ''
+    }),
+    submoduleSync: jest.fn(),
+    submoduleUpdate: jest.fn(),
+    tagExists: jest.fn(),
+    tryClean: jest.fn(),
+    tryConfigUnset: jest.fn(
+      async (key: string, globalConfig?: boolean): Promise<boolean> => {
+        const configPath = globalConfig
+          ? path.join(git.env['HOME'] || tempHomedir, '.gitconfig')
+          : localGitConfigPath
+        let content = await fs.promises.readFile(configPath)
+        let lines = content
+          .toString()
+          .split('\n')
+          .filter(x => x)
+          .filter(x => !x.startsWith(key))
+        await fs.promises.writeFile(configPath, lines.join('\n'))
+        return true
+      }
+    ),
+    tryDisableAutomaticGarbageCollection: jest.fn(),
+    tryGetFetchUrl: jest.fn(),
+    tryReset: jest.fn()
+  }
+
+  settings = {
+    authToken: 'some auth token',
+    clean: true,
+    commit: '',
+    fetchDepth: 1,
+    lfs: false,
+    submodules: false,
+    nestedSubmodules: false,
+    persistCredentials: true,
+    ref: 'refs/heads/master',
+    repositoryName: 'my-repo',
+    repositoryOwner: 'my-org',
+    repositoryPath: '',
+    sshKey: sshPath ? 'some ssh private key' : '',
+    sshKnownHosts: '',
+    sshStrict: true
+  }
+}
+
+async function getActualSshKeyPath(): Promise<string> {
+  let actualTempFiles = (await fs.promises.readdir(runnerTemp))
+    .sort()
+    .map(x => path.join(runnerTemp, x))
+  if (actualTempFiles.length === 0) {
+    return ''
+  }
+
+  expect(actualTempFiles).toHaveLength(2)
+  expect(actualTempFiles[0].endsWith('_known_hosts')).toBeFalsy()
+  return actualTempFiles[0]
+}
+
+async function getActualSshKnownHostsPath(): Promise<string> {
+  let actualTempFiles = (await fs.promises.readdir(runnerTemp))
+    .sort()
+    .map(x => path.join(runnerTemp, x))
+  if (actualTempFiles.length === 0) {
+    return ''
+  }
+
+  expect(actualTempFiles).toHaveLength(2)
+  expect(actualTempFiles[1].endsWith('_known_hosts')).toBeTruthy()
+  expect(actualTempFiles[1].startsWith(actualTempFiles[0])).toBeTruthy()
+  return actualTempFiles[1]
+}

__test__/git-directory-helper.test.ts

@@ -0,0 +1,441 @@
+import * as core from '@actions/core'
+import * as fs from 'fs'
+import * as gitDirectoryHelper from '../lib/git-directory-helper'
+import * as io from '@actions/io'
+import * as path from 'path'
+import {IGitCommandManager} from '../lib/git-command-manager'
+
+const testWorkspace = path.join(__dirname, '_temp', 'git-directory-helper')
+let repositoryPath: string
+let repositoryUrl: string
+let clean: boolean
+let ref: string
+let git: IGitCommandManager
+
+describe('git-directory-helper tests', () => {
+  beforeAll(async () => {
+    // Clear test workspace
+    await io.rmRF(testWorkspace)
+  })
+
+  beforeEach(() => {
+    // Mock error/warning/info/debug
+    jest.spyOn(core, 'error').mockImplementation(jest.fn())
+    jest.spyOn(core, 'warning').mockImplementation(jest.fn())
+    jest.spyOn(core, 'info').mockImplementation(jest.fn())
+    jest.spyOn(core, 'debug').mockImplementation(jest.fn())
+  })
+
+  afterEach(() => {
+    // Unregister mocks
+    jest.restoreAllMocks()
+  })
+
+  const cleansWhenCleanTrue = 'cleans when clean true'
+  it(cleansWhenCleanTrue, async () => {
+    // Arrange
+    await setup(cleansWhenCleanTrue)
+    await fs.promises.writeFile(path.join(repositoryPath, 'my-file'), '')
+
+    // Act
+    await gitDirectoryHelper.prepareExistingDirectory(
+      git,
+      repositoryPath,
+      repositoryUrl,
+      clean,
+      ref
+    )
+
+    // Assert
+    const files = await fs.promises.readdir(repositoryPath)
+    expect(files.sort()).toEqual(['.git', 'my-file'])
+    expect(git.tryClean).toHaveBeenCalled()
+    expect(git.tryReset).toHaveBeenCalled()
+    expect(core.warning).not.toHaveBeenCalled()
+  })
+
+  const checkoutDetachWhenNotDetached = 'checkout detach when not detached'
+  it(checkoutDetachWhenNotDetached, async () => {
+    // Arrange
+    await setup(checkoutDetachWhenNotDetached)
+    await fs.promises.writeFile(path.join(repositoryPath, 'my-file'), '')
+
+    // Act
+    await gitDirectoryHelper.prepareExistingDirectory(
+      git,
+      repositoryPath,
+      repositoryUrl,
+      clean,
+      ref
+    )
+
+    // Assert
+    const files = await fs.promises.readdir(repositoryPath)
+    expect(files.sort()).toEqual(['.git', 'my-file'])
+    expect(git.checkoutDetach).toHaveBeenCalled()
+  })
+
+  const doesNotCheckoutDetachWhenNotAlreadyDetached =
+    'does not checkout detach when already detached'
+  it(doesNotCheckoutDetachWhenNotAlreadyDetached, async () => {
+    // Arrange
+    await setup(doesNotCheckoutDetachWhenNotAlreadyDetached)
+    await fs.promises.writeFile(path.join(repositoryPath, 'my-file'), '')
+    const mockIsDetached = git.isDetached as jest.Mock<any, any>
+    mockIsDetached.mockImplementation(async () => {
+      return true
+    })
+
+    // Act
+    await gitDirectoryHelper.prepareExistingDirectory(
+      git,
+      repositoryPath,
+      repositoryUrl,
+      clean,
+      ref
+    )
+
+    // Assert
+    const files = await fs.promises.readdir(repositoryPath)
+    expect(files.sort()).toEqual(['.git', 'my-file'])
+    expect(git.checkoutDetach).not.toHaveBeenCalled()
+  })
+
+  const doesNotCleanWhenCleanFalse = 'does not clean when clean false'
+  it(doesNotCleanWhenCleanFalse, async () => {
+    // Arrange
+    await setup(doesNotCleanWhenCleanFalse)
+    clean = false
+    await fs.promises.writeFile(path.join(repositoryPath, 'my-file'), '')
+
+    // Act
+    await gitDirectoryHelper.prepareExistingDirectory(
+      git,
+      repositoryPath,
+      repositoryUrl,
+      clean,
+      ref
+    )
+
+    // Assert
+    const files = await fs.promises.readdir(repositoryPath)
+    expect(files.sort()).toEqual(['.git', 'my-file'])
+    expect(git.isDetached).toHaveBeenCalled()
+    expect(git.branchList).toHaveBeenCalled()
+    expect(core.warning).not.toHaveBeenCalled()
+    expect(git.tryClean).not.toHaveBeenCalled()
+    expect(git.tryReset).not.toHaveBeenCalled()
+  })
+
+  const removesContentsWhenCleanFails = 'removes contents when clean fails'
+  it(removesContentsWhenCleanFails, async () => {
+    // Arrange
+    await setup(removesContentsWhenCleanFails)
+    await fs.promises.writeFile(path.join(repositoryPath, 'my-file'), '')
+    let mockTryClean = git.tryClean as jest.Mock<any, any>
+    mockTryClean.mockImplementation(async () => {
+      return false
+    })
+
+    // Act
+    await gitDirectoryHelper.prepareExistingDirectory(
+      git,
+      repositoryPath,
+      repositoryUrl,
+      clean,
+      ref
+    )
+
+    // Assert
+    const files = await fs.promises.readdir(repositoryPath)
+    expect(files).toHaveLength(0)
+    expect(git.tryClean).toHaveBeenCalled()
+    expect(core.warning).toHaveBeenCalled()
+    expect(git.tryReset).not.toHaveBeenCalled()
+  })
+
+  const removesContentsWhenDifferentRepositoryUrl =
+    'removes contents when different repository url'
+  it(removesContentsWhenDifferentRepositoryUrl, async () => {
+    // Arrange
+    await setup(removesContentsWhenDifferentRepositoryUrl)
+    clean = false
+    await fs.promises.writeFile(path.join(repositoryPath, 'my-file'), '')
+    const differentRepositoryUrl =
+      'https://github.com/my-different-org/my-different-repo'
+
+    // Act
+    await gitDirectoryHelper.prepareExistingDirectory(
+      git,
+      repositoryPath,
+      differentRepositoryUrl,
+      clean,
+      ref
+    )
+
+    // Assert
+    const files = await fs.promises.readdir(repositoryPath)
+    expect(files).toHaveLength(0)
+    expect(core.warning).not.toHaveBeenCalled()
+    expect(git.isDetached).not.toHaveBeenCalled()
+  })
+
+  const removesContentsWhenNoGitDirectory =
+    'removes contents when no git directory'
+  it(removesContentsWhenNoGitDirectory, async () => {
+    // Arrange
+    await setup(removesContentsWhenNoGitDirectory)
+    clean = false
+    await io.rmRF(path.join(repositoryPath, '.git'))
+    await fs.promises.writeFile(path.join(repositoryPath, 'my-file'), '')
+
+    // Act
+    await gitDirectoryHelper.prepareExistingDirectory(
+      git,
+      repositoryPath,
+      repositoryUrl,
+      clean,
+      ref
+    )
+
+    // Assert
+    const files = await fs.promises.readdir(repositoryPath)
+    expect(files).toHaveLength(0)
+    expect(core.warning).not.toHaveBeenCalled()
+    expect(git.isDetached).not.toHaveBeenCalled()
+  })
+
+  const removesContentsWhenResetFails = 'removes contents when reset fails'
+  it(removesContentsWhenResetFails, async () => {
+    // Arrange
+    await setup(removesContentsWhenResetFails)
+    await fs.promises.writeFile(path.join(repositoryPath, 'my-file'), '')
+    let mockTryReset = git.tryReset as jest.Mock<any, any>
+    mockTryReset.mockImplementation(async () => {
+      return false
+    })
+
+    // Act
+    await gitDirectoryHelper.prepareExistingDirectory(
+      git,
+      repositoryPath,
+      repositoryUrl,
+      clean,
+      ref
+    )
+
+    // Assert
+    const files = await fs.promises.readdir(repositoryPath)
+    expect(files).toHaveLength(0)
+    expect(git.tryClean).toHaveBeenCalled()
+    expect(git.tryReset).toHaveBeenCalled()
+    expect(core.warning).toHaveBeenCalled()
+  })
+
+  const removesContentsWhenUndefinedGitCommandManager =
+    'removes contents when undefined git command manager'
+  it(removesContentsWhenUndefinedGitCommandManager, async () => {
+    // Arrange
+    await setup(removesContentsWhenUndefinedGitCommandManager)
+    clean = false
+    await fs.promises.writeFile(path.join(repositoryPath, 'my-file'), '')
+
+    // Act
+    await gitDirectoryHelper.prepareExistingDirectory(
+      undefined,
+      repositoryPath,
+      repositoryUrl,
+      clean,
+      ref
+    )
+
+    // Assert
+    const files = await fs.promises.readdir(repositoryPath)
+    expect(files).toHaveLength(0)
+    expect(core.warning).not.toHaveBeenCalled()
+  })
+
+  const removesLocalBranches = 'removes local branches'
+  it(removesLocalBranches, async () => {
+    // Arrange
+    await setup(removesLocalBranches)
+    await fs.promises.writeFile(path.join(repositoryPath, 'my-file'), '')
+    const mockBranchList = git.branchList as jest.Mock<any, any>
+    mockBranchList.mockImplementation(async (remote: boolean) => {
+      return remote ? [] : ['local-branch-1', 'local-branch-2']
+    })
+
+    // Act
+    await gitDirectoryHelper.prepareExistingDirectory(
+      git,
+      repositoryPath,
+      repositoryUrl,
+      clean,
+      ref
+    )
+
+    // Assert
+    const files = await fs.promises.readdir(repositoryPath)
+    expect(files.sort()).toEqual(['.git', 'my-file'])
+    expect(git.branchDelete).toHaveBeenCalledWith(false, 'local-branch-1')
+    expect(git.branchDelete).toHaveBeenCalledWith(false, 'local-branch-2')
+  })
+
+  const removesLockFiles = 'removes lock files'
+  it(removesLockFiles, async () => {
+    // Arrange
+    await setup(removesLockFiles)
+    clean = false
+    await fs.promises.writeFile(
+      path.join(repositoryPath, '.git', 'index.lock'),
+      ''
+    )
+    await fs.promises.writeFile(
+      path.join(repositoryPath, '.git', 'shallow.lock'),
+      ''
+    )
+    await fs.promises.writeFile(path.join(repositoryPath, 'my-file'), '')
+
+    // Act
+    await gitDirectoryHelper.prepareExistingDirectory(
+      git,
+      repositoryPath,
+      repositoryUrl,
+      clean,
+      ref
+    )
+
+    // Assert
+    let files = await fs.promises.readdir(path.join(repositoryPath, '.git'))
+    expect(files).toHaveLength(0)
+    files = await fs.promises.readdir(repositoryPath)
+    expect(files.sort()).toEqual(['.git', 'my-file'])
+    expect(git.isDetached).toHaveBeenCalled()
+    expect(git.branchList).toHaveBeenCalled()
+    expect(core.warning).not.toHaveBeenCalled()
+    expect(git.tryClean).not.toHaveBeenCalled()
+    expect(git.tryReset).not.toHaveBeenCalled()
+  })
+
+  const removesAncestorRemoteBranch = 'removes ancestor remote branch'
+  it(removesAncestorRemoteBranch, async () => {
+    // Arrange
+    await setup(removesAncestorRemoteBranch)
+    await fs.promises.writeFile(path.join(repositoryPath, 'my-file'), '')
+    const mockBranchList = git.branchList as jest.Mock<any, any>
+    mockBranchList.mockImplementation(async (remote: boolean) => {
+      return remote ? ['origin/remote-branch-1', 'origin/remote-branch-2'] : []
+    })
+    ref = 'remote-branch-1/conflict'
+
+    // Act
+    await gitDirectoryHelper.prepareExistingDirectory(
+      git,
+      repositoryPath,
+      repositoryUrl,
+      clean,
+      ref
+    )
+
+    // Assert
+    const files = await fs.promises.readdir(repositoryPath)
+    expect(files.sort()).toEqual(['.git', 'my-file'])
+    expect(git.branchDelete).toHaveBeenCalledTimes(1)
+    expect(git.branchDelete).toHaveBeenCalledWith(
+      true,
+      'origin/remote-branch-1'
+    )
+  })
+
+  const removesDescendantRemoteBranches = 'removes descendant remote branch'
+  it(removesDescendantRemoteBranches, async () => {
+    // Arrange
+    await setup(removesDescendantRemoteBranches)
+    await fs.promises.writeFile(path.join(repositoryPath, 'my-file'), '')
+    const mockBranchList = git.branchList as jest.Mock<any, any>
+    mockBranchList.mockImplementation(async (remote: boolean) => {
+      return remote
+        ? ['origin/remote-branch-1/conflict', 'origin/remote-branch-2']
+        : []
+    })
+    ref = 'remote-branch-1'
+
+    // Act
+    await gitDirectoryHelper.prepareExistingDirectory(
+      git,
+      repositoryPath,
+      repositoryUrl,
+      clean,
+      ref
+    )
+
+    // Assert
+    const files = await fs.promises.readdir(repositoryPath)
+    expect(files.sort()).toEqual(['.git', 'my-file'])
+    expect(git.branchDelete).toHaveBeenCalledTimes(1)
+    expect(git.branchDelete).toHaveBeenCalledWith(
+      true,
+      'origin/remote-branch-1/conflict'
+    )
+  })
+})
+
+async function setup(testName: string): Promise<void> {
+  testName = testName.replace(/[^a-zA-Z0-9_]+/g, '-')
+
+  // Repository directory
+  repositoryPath = path.join(testWorkspace, testName)
+  await fs.promises.mkdir(path.join(repositoryPath, '.git'), {recursive: true})
+
+  // Repository URL
+  repositoryUrl = 'https://github.com/my-org/my-repo'
+
+  // Clean
+  clean = true
+
+  // Ref
+  ref = ''
+
+  // Git command manager
+  git = {
+    branchDelete: jest.fn(),
+    branchExists: jest.fn(),
+    branchList: jest.fn(async () => {
+      return []
+    }),
+    checkout: jest.fn(),
+    checkoutDetach: jest.fn(),
+    config: jest.fn(),
+    configExists: jest.fn(),
+    fetch: jest.fn(),
+    getDefaultBranch: jest.fn(),
+    getWorkingDirectory: jest.fn(() => repositoryPath),
+    init: jest.fn(),
+    isDetached: jest.fn(),
+    lfsFetch: jest.fn(),
+    lfsInstall: jest.fn(),
+    log1: jest.fn(),
+    remoteAdd: jest.fn(),
+    removeEnvironmentVariable: jest.fn(),
+    revParse: jest.fn(),
+    setEnvironmentVariable: jest.fn(),
+    shaExists: jest.fn(),
+    submoduleForeach: jest.fn(),
+    submoduleSync: jest.fn(),
+    submoduleUpdate: jest.fn(),
+    tagExists: jest.fn(),
+    tryClean: jest.fn(async () => {
+      return true
+    }),
+    tryConfigUnset: jest.fn(),
+    tryDisableAutomaticGarbageCollection: jest.fn(),
+    tryGetFetchUrl: jest.fn(async () => {
+      // Sanity check - this function shouldn't be called when the .git directory doesn't exist
+      await fs.promises.stat(path.join(repositoryPath, '.git'))
+      return repositoryUrl
+    }),
+    tryReset: jest.fn(async () => {
+      return true
+    })
+  }
+}

__test__/input-helper.test.ts

@@ -1,47 +1,50 @@
 import * as assert from 'assert'
+import * as core from '@actions/core'
+import * as fsHelper from '../lib/fs-helper'
+import * as github from '@actions/github'
+import * as inputHelper from '../lib/input-helper'
 import * as path from 'path'
-import {ISourceSettings} from '../lib/git-source-provider'
+import {IGitSourceSettings} from '../lib/git-source-settings'
 
 const originalGitHubWorkspace = process.env['GITHUB_WORKSPACE']
 const gitHubWorkspace = path.resolve('/checkout-tests/workspace')
 
-// Late bind
+// Inputs for mock @actions/core
-let inputHelper: any
-
-// Mock @actions/core
 let inputs = {} as any
-const mockCore = jest.genMockFromModule('@actions/core') as any
-mockCore.getInput = (name: string) => {
-  return inputs[name]
-}
 
-// Mock @actions/github
+// Shallow clone original @actions/github context
-const mockGitHub = jest.genMockFromModule('@actions/github') as any
+let originalContext = {...github.context}
-mockGitHub.context = {
-  repo: {
-    owner: 'some-owner',
-    repo: 'some-repo'
-  },
-  ref: 'refs/heads/some-ref',
-  sha: '1234567890123456789012345678901234567890'
-}
-
-// Mock ./fs-helper
-const mockFSHelper = jest.genMockFromModule('../lib/fs-helper') as any
-mockFSHelper.directoryExistsSync = (path: string) => path == gitHubWorkspace
 
 describe('input-helper tests', () => {
   beforeAll(() => {
+    // Mock getInput
+    jest.spyOn(core, 'getInput').mockImplementation((name: string) => {
+      return inputs[name]
+    })
+
+    // Mock error/warning/info/debug
+    jest.spyOn(core, 'error').mockImplementation(jest.fn())
+    jest.spyOn(core, 'warning').mockImplementation(jest.fn())
+    jest.spyOn(core, 'info').mockImplementation(jest.fn())
+    jest.spyOn(core, 'debug').mockImplementation(jest.fn())
+
+    // Mock github context
+    jest.spyOn(github.context, 'repo', 'get').mockImplementation(() => {
+      return {
+        owner: 'some-owner',
+        repo: 'some-repo'
+      }
+    })
+    github.context.ref = 'refs/heads/some-ref'
+    github.context.sha = '1234567890123456789012345678901234567890'
+
+    // Mock ./fs-helper directoryExistsSync()
+    jest
+      .spyOn(fsHelper, 'directoryExistsSync')
+      .mockImplementation((path: string) => path == gitHubWorkspace)
+
     // GitHub workspace
     process.env['GITHUB_WORKSPACE'] = gitHubWorkspace
-
-    // Mocks
-    jest.setMock('@actions/core', mockCore)
-    jest.setMock('@actions/github', mockGitHub)
-    jest.setMock('../lib/fs-helper', mockFSHelper)
-
-    // Now import
-    inputHelper = require('../lib/input-helper')
   })
 
   beforeEach(() => {
@@ -50,18 +53,22 @@ describe('input-helper tests', () => {
   })
 
   afterAll(() => {
-    // Reset GitHub workspace
+    // Restore GitHub workspace
     delete process.env['GITHUB_WORKSPACE']
     if (originalGitHubWorkspace) {
       process.env['GITHUB_WORKSPACE'] = originalGitHubWorkspace
     }
 
-    // Reset modules
+    // Restore @actions/github context
-    jest.resetModules()
+    github.context.ref = originalContext.ref
+    github.context.sha = originalContext.sha
+
+    // Restore
+    jest.restoreAllMocks()
   })
 
   it('sets defaults', () => {
-    const settings: ISourceSettings = inputHelper.getInputs()
+    const settings: IGitSourceSettings = inputHelper.getInputs()
     expect(settings).toBeTruthy()
     expect(settings.authToken).toBeFalsy()
     expect(settings.clean).toBe(true)
@@ -75,6 +82,19 @@ describe('input-helper tests', () => {
     expect(settings.repositoryPath).toBe(gitHubWorkspace)
   })
 
+  it('qualifies ref', () => {
+    let originalRef = github.context.ref
+    try {
+      github.context.ref = 'some-unqualified-ref'
+      const settings: IGitSourceSettings = inputHelper.getInputs()
+      expect(settings).toBeTruthy()
+      expect(settings.commit).toBe('1234567890123456789012345678901234567890')
+      expect(settings.ref).toBe('refs/heads/some-unqualified-ref')
+    } finally {
+      github.context.ref = originalRef
+    }
+  })
+
   it('requires qualified repo', () => {
     inputs.repository = 'some-unqualified-repo'
     assert.throws(() => {
@@ -84,37 +104,23 @@ describe('input-helper tests', () => {
 
   it('roots path', () => {
     inputs.path = 'some-directory/some-subdirectory'
-    const settings: ISourceSettings = inputHelper.getInputs()
+    const settings: IGitSourceSettings = inputHelper.getInputs()
     expect(settings.repositoryPath).toBe(
       path.join(gitHubWorkspace, 'some-directory', 'some-subdirectory')
     )
   })
 
-  it('sets correct default ref/sha for other repo', () => {
-    inputs.repository = 'some-owner/some-other-repo'
-    const settings: ISourceSettings = inputHelper.getInputs()
-    expect(settings.ref).toBe('refs/heads/master')
-    expect(settings.commit).toBeFalsy()
-  })
-
   it('sets ref to empty when explicit sha', () => {
     inputs.ref = '1111111111222222222233333333334444444444'
-    const settings: ISourceSettings = inputHelper.getInputs()
+    const settings: IGitSourceSettings = inputHelper.getInputs()
     expect(settings.ref).toBeFalsy()
     expect(settings.commit).toBe('1111111111222222222233333333334444444444')
   })
 
   it('sets sha to empty when explicit ref', () => {
     inputs.ref = 'refs/heads/some-other-ref'
-    const settings: ISourceSettings = inputHelper.getInputs()
+    const settings: IGitSourceSettings = inputHelper.getInputs()
     expect(settings.ref).toBe('refs/heads/some-other-ref')
     expect(settings.commit).toBeFalsy()
   })
-
-  it('gives good error message for submodules input', () => {
-    inputs.submodules = 'true'
-    assert.throws(() => {
-      inputHelper.getInputs()
-    }, /The input 'submodules' is not supported/)
-  })
 })

__test__/override-git-version.cmd

@@ -0,0 +1,6 @@
+
+mkdir override-git-version
+cd override-git-version
+echo @echo override git version 1.2.3 > git.cmd
+echo ::add-path::%CD%
+cd ..

__test__/override-git-version.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+mkdir override-git-version
+cd override-git-version
+echo "#!/bin/sh" > git
+echo "echo override git version 1.2.3" >> git
+chmod +x git
+echo "::add-path::$(pwd)"
+cd ..

__test__/retry-helper.test.ts

@@ -1,18 +1,17 @@
-const mockCore = jest.genMockFromModule('@actions/core') as any
+import * as core from '@actions/core'
-mockCore.info = (message: string) => {
+import {RetryHelper} from '../lib/retry-helper'
-  info.push(message)
+
-}
 let info: string[]
 let retryHelper: any
 
 describe('retry-helper tests', () => {
   beforeAll(() => {
-    // Mocks
+    // Mock @actions/core info()
-    jest.setMock('@actions/core', mockCore)
+    jest.spyOn(core, 'info').mockImplementation((message: string) => {
+      info.push(message)
+    })
 
-    // Now import
+    retryHelper = new RetryHelper(3, 0, 0)
-    const retryHelperModule = require('../lib/retry-helper')
-    retryHelper = new retryHelperModule.RetryHelper(3, 0, 0)
   })
 
   beforeEach(() => {
@@ -21,8 +20,8 @@ describe('retry-helper tests', () => {
   })
 
   afterAll(() => {
-    // Reset modules
+    // Restore
-    jest.resetModules()
+    jest.restoreAllMocks()
   })
 
   it('first attempt succeeds', async () => {

__test__/verify-no-unstaged-changes.sh

@@ -12,6 +12,6 @@ if [[ "$(git status --porcelain)" != "" ]]; then
     echo ----------------------------------------
     echo Troubleshooting
     echo ----------------------------------------
-    echo "::error::Unstaged changes detected. Locally try running: git clean -ffdx && npm ci && npm run all"
+    echo "::error::Unstaged changes detected. Locally try running: git clean -ffdx && npm ci && npm run format && npm run build"
     exit 1
 fi

__test__/verify-submodules-false.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+if [ ! -f "./submodules-false/regular-file.txt" ]; then
+    echo "Expected regular file does not exist"
+    exit 1
+fi
+
+if [ -f "./submodules-false/submodule-level-1/submodule-file.txt" ]; then
+    echo "Unexpected submodule file exists"
+    exit 1
+fi

__test__/verify-submodules-not-checked-out.sh

@@ -1,11 +0,0 @@
-#!/bin/bash
-
-if [ ! -f "./submodules-not-checked-out/regular-file.txt" ]; then
-    echo "Expected regular file does not exist"
-    exit 1
-fi
-
-if [ -f "./submodules-not-checked-out/submodule-level-1/submodule-file.txt" ]; then
-    echo "Unexpected submodule file exists"
-    exit 1
-fi

__test__/verify-submodules-recursive.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+if [ ! -f "./submodules-recursive/regular-file.txt" ]; then
+    echo "Expected regular file does not exist"
+    exit 1
+fi
+
+if [ ! -f "./submodules-recursive/submodule-level-1/submodule-file.txt" ]; then
+    echo "Expected submodule file does not exist"
+    exit 1
+fi
+
+if [ ! -f "./submodules-recursive/submodule-level-1/submodule-level-2/nested-submodule-file.txt" ]; then
+    echo "Expected nested submodule file does not exists"
+    exit 1
+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
+if [ "$?" != "0" ]; then
+    echo "Failed to validate persisted credential"
+    popd
+    exit 1
+fi
+popd

__test__/verify-submodules-true.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+if [ ! -f "./submodules-true/regular-file.txt" ]; then
+    echo "Expected regular file does not exist"
+    exit 1
+fi
+
+if [ ! -f "./submodules-true/submodule-level-1/submodule-file.txt" ]; then
+    echo "Expected submodule file does not exist"
+    exit 1
+fi
+
+if [ -f "./submodules-true/submodule-level-1/submodule-level-2/nested-submodule-file.txt" ]; then
+    echo "Unexpected nested submodule file exists"
+    exit 1
+fi
+
+echo "Testing persisted credential"
+pushd ./submodules-true/submodule-level-1
+git config --local --name-only --get-regexp http.+extraheader && git fetch
+if [ "$?" != "0" ]; then
+    echo "Failed to validate persisted credential"
+    popd
+    exit 1
+fi
+popd

action.yml

@@ -1,6 +1,6 @@
 name: 'Checkout'
 description: 'Checkout a Git repository at a particular version'
-inputs: 
+inputs:
   repository:
     description: 'Repository name with owner. For example, actions/checkout'
     default: ${{ github.repository }}
@@ -8,16 +8,45 @@ inputs:
     description: >
       The branch, tag or SHA to checkout. When checking out the repository that
       triggered a workflow, this defaults to the reference or SHA for that
-      event.  Otherwise, defaults to `master`.
+      event.  Otherwise, uses the default branch.
   token:
     description: >
-      Auth token used to fetch the repository. The token is stored in the local
+      Personal access token (PAT) used to fetch the repository. The PAT is configured
-      git config, which enables your scripts to run authenticated git commands.
+      with the local git config, which enables your scripts to run authenticated git
-      The post-job step removes the token from the git config. [Learn more about
+      commands. The post-job step removes the PAT.
-      creating and using encrypted secrets](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/creating-and-using-encrypted-secrets)
+
+
+      We recommend using a service account with the least permissions necessary.
+      Also when generating a new PAT, select the least scopes necessary.
+
+
+      [Learn more about creating and using encrypted secrets](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/creating-and-using-encrypted-secrets)
     default: ${{ github.token }}
+  ssh-key:
+    description: >
+      SSH key used to fetch the repository. The SSH key is configured with the local
+      git config, which enables your scripts to run authenticated git commands.
+      The post-job step removes the SSH key.
+
+
+      We recommend using a service account with the least permissions necessary.
+
+
+      [Learn more about creating and using
+      encrypted secrets](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/creating-and-using-encrypted-secrets)
+  ssh-known-hosts:
+    description: >
+      Known hosts in addition to the user and global host key database. The public
+      SSH keys for a host may be obtained using the utility `ssh-keyscan`. For example,
+      `ssh-keyscan github.com`. The public key for github.com is always implicitly added.
+  ssh-strict:
+    description: >
+      Whether to perform strict host key checking. When true, adds the options `StrictHostKeyChecking=yes`
+      and `CheckHostIP=no` to the SSH command line. Use the input `ssh-known-hosts` to
+      configure additional hosts.
+    default: true
   persist-credentials:
-    description: 'Whether to persist the token in the git config'
+    description: 'Whether to configure the token or SSH key with the local git config'
     default: true
   path:
     description: 'Relative path under $GITHUB_WORKSPACE to place the repository'
@@ -25,11 +54,20 @@ inputs:
     description: 'Whether to execute `git clean -ffdx && git reset --hard HEAD` before fetching'
     default: true
   fetch-depth:
-    description: 'Number of commits to fetch. 0 indicates all history.'
+    description: 'Number of commits to fetch. 0 indicates all history for all branches and tags.'
     default: 1
   lfs:
     description: 'Whether to download Git-LFS files'
     default: false
+  submodules:
+    description: >
+      Whether to checkout submodules: `true` to checkout submodules or `recursive` to
+      recursively checkout submodules.
+
+
+      When the `ssh-key` input is not provided, SSH URLs beginning with `git@github.com:` are
+      converted to HTTPS.
+    default: false
 runs:
   using: node12
   main: dist/index.js

adrs/0153-checkout-v2.md

@@ -0,0 +1,290 @@
+# ADR 0153: Checkout v2
+
+**Date**: 2019-10-21
+
+**Status**: Accepted
+
+## Context
+
+This ADR details the behavior for `actions/checkout@v2`.
+
+The new action will be written in typescript. We are moving away from runner-plugin actions.
+
+We want to take this opportunity to make behavioral changes, from v1. This document is scoped to those differences.
+
+## Decision
+
+### Inputs
+
+```yaml
+  repository:
+    description: 'Repository name with owner. For example, actions/checkout'
+    default: ${{ github.repository }}
+  ref:
+    description: >
+      The branch, tag or SHA to checkout. When checking out the repository that
+      triggered a workflow, this defaults to the reference or SHA for that
+      event.  Otherwise, defaults to `master`.
+  token:
+    description: >
+      Personal access token (PAT) used to fetch the repository. The PAT is configured
+      with the local git config, which enables your scripts to run authenticated git
+      commands. The post-job step removes the PAT.
+
+
+      We recommend using a service account with the least permissions necessary.
+      Also when generating a new PAT, select the least scopes necessary.
+
+
+      [Learn more about creating and using encrypted secrets](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/creating-and-using-encrypted-secrets)
+    default: ${{ github.token }}
+  ssh-key:
+    description: >
+      SSH key used to fetch the repository. The SSH key is configured with the local
+      git config, which enables your scripts to run authenticated git commands.
+      The post-job step removes the SSH key.
+
+
+      We recommend using a service account with the least permissions necessary.
+
+
+      [Learn more about creating and using
+      encrypted secrets](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/creating-and-using-encrypted-secrets)
+  ssh-known-hosts:
+    description: >
+      Known hosts in addition to the user and global host key database. The public
+      SSH keys for a host may be obtained using the utility `ssh-keyscan`. For example,
+      `ssh-keyscan github.com`. The public key for github.com is always implicitly added.
+  ssh-strict:
+    description: >
+      Whether to perform strict host key checking. When true, adds the options `StrictHostKeyChecking=yes`
+      and `CheckHostIP=no` to the SSH command line. Use the input `ssh-known-hosts` to
+      configure additional hosts.
+    default: true
+  persist-credentials:
+    description: 'Whether to configure the token or SSH key with the local git config'
+    default: true
+  path:
+    description: 'Relative path under $GITHUB_WORKSPACE to place the repository'
+  clean:
+    description: 'Whether to execute `git clean -ffdx && git reset --hard HEAD` before fetching'
+    default: true
+  fetch-depth:
+    description: 'Number of commits to fetch. 0 indicates all history for all tags and branches.'
+    default: 1
+  lfs:
+    description: 'Whether to download Git-LFS files'
+    default: false
+  submodules:
+    description: >
+      Whether to checkout submodules: `true` to checkout submodules or `recursive` to
+      recursively checkout submodules.
+
+
+      When the `ssh-key` input is not provided, SSH URLs beginning with `git@github.com:` are
+      converted to HTTPS.
+    default: false
+```
+
+Note:
+- SSH support is new
+- `persist-credentials` is new
+- `path` behavior is different (refer [below](#path) for details)
+
+### Fallback to GitHub API
+
+When a sufficient version of git is not in the PATH, fallback to the [web API](https://developer.github.com/v3/repos/contents/#get-archive-link) to download a tarball/zipball.
+
+Note:
+- LFS files are not included in the archive. Therefore fail if LFS is set to true.
+- Submodules are also not included in the archive.
+
+### Persist credentials
+
+The credentials will be persisted on disk. This will allow users to script authenticated git commands, like `git fetch`.
+
+A post script will remove the credentials (cleanup for self-hosted).
+
+Users may opt-out by specifying `persist-credentials: false`
+
+Note:
+- Users scripting `git commit` may need to set the username and email. The service does not provide any reasonable default value. Users can add `git config user.name <NAME>` and `git config user.email <EMAIL>`. We will document this guidance.
+
+#### PAT
+
+When using the `${{github.token}}` or a PAT, the token will be persisted in the local git config. The config key `http.https://github.com/.extraheader` enables an auth header to be specified on all authenticated commands `AUTHORIZATION: basic <BASE64_U:P>`.
+
+Note:
+- The auth header is scoped to all of github `http.https://github.com/.extraheader`
+  - Additional public remotes also just work.
+  - If users want to authenticate to an additional private remote, they should provide the `token` input.
+
+#### SSH key
+
+The SSH key will be written to disk under the `$RUNNER_TEMP` directory. The SSH key will
+be removed by the action's post-job hook. Additionally, RUNNER_TEMP is cleared by the
+runner between jobs.
+
+The SSH key must be written with strict file permissions. The SSH client requires the file
+to be read/write for the user, and not accessible by others.
+
+The user host key database (`~/.ssh/known_hosts`) will be copied to a unique file under
+`$RUNNER_TEMP`. And values from the input `ssh-known-hosts` will be added to the file.
+
+The SSH command will be overridden for the local git config:
+
+```sh
+git config core.sshCommand 'ssh -i "$RUNNER_TEMP/path-to-ssh-key" -o StrictHostKeyChecking=yes -o CheckHostIP=no -o "UserKnownHostsFile=$RUNNER_TEMP/path-to-known-hosts"'
+```
+
+When the input `ssh-strict` is set to `false`, the options `CheckHostIP` and `StrictHostKeyChecking` will not be overridden.
+
+Note:
+- When `ssh-strict` is set to `true` (default), the SSH option `CheckHostIP` can safely be disabled.
+  Strict host checking verifies the server's public key. Therefore, IP verification is unnecessary
+  and noisy. For example:
+  > Warning: Permanently added the RSA host key for IP address '140.82.113.4' to the list of known hosts.
+- Since GIT_SSH_COMMAND overrides core.sshCommand, temporarily set the env var when fetching the repo. When creds
+  are persisted, core.sshCommand is leveraged to avoid multiple checkout steps stomping over each other.
+- Modify actions/runner to mount RUNNER_TEMP to enable scripting authenticated git commands from a container action.
+- Refer [here](https://linux.die.net/man/5/ssh_config) for SSH config details.
+
+### Fetch behavior
+
+Fetch only the SHA being built and set depth=1. This significantly reduces the fetch time for large repos.
+
+If a SHA isn't available (e.g. multi repo), then fetch only the specified ref with depth=1.
+
+The input `fetch-depth` can be used to control the depth.
+
+Note:
+- Fetching a single commit is supported by Git wire protocol version 2. The git client uses protocol version 0 by default. The desired protocol version can be overridden in the git config or on the fetch command line invocation (`-c protocol.version=2`). We will override on the fetch command line, for transparency.
+- Git client version 2.18+ (released June 2018) is required for wire protocol version 2.
+
+### Checkout behavior
+
+For CI, checkout will create a local ref with the upstream set. This allows users to script git as they normally would.
+
+For PR, continue to checkout detached head. The PR branch is special - the branch and merge commit are created by the server. It doesn't match a users' local workflow.
+
+Note:
+- Consider deleting all local refs during cleanup if that helps avoid collisions. More testing required.
+
+### Path
+
+For the mainline scenario, the disk-layout behavior remains the same.
+
+Remember, given the repo `johndoe/foo`, the mainline disk layout looks like:
+
+```
+GITHUB_WORKSPACE=/home/runner/work/foo/foo
+RUNNER_WORKSPACE=/home/runner/work/foo
+```
+
+V2 introduces a new contraint on the checkout path. The location must now be under `github.workspace`. Whereas the checkout@v1 constraint was one level up, under `runner.workspace`.
+
+V2 no longer changes `github.workspace` to follow wherever the self repo is checked-out.
+
+These behavioral changes align better with container actions. The [documented filesystem contract](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/virtual-environments-for-github-hosted-runners#docker-container-filesystem) is:
+
+- `/github/home`
+- `/github/workspace` - Note: GitHub Actions must be run by the default Docker user (root). Ensure your Dockerfile does not set the USER instruction, otherwise you will not be able to access `GITHUB_WORKSPACE`.
+- `/github/workflow`
+
+Note:
+- The tracking config will not be updated to reflect the path of the workflow repo.
+- Any existing workflow repo will not be moved when the checkout path changes. In fact some customers want to checkout the workflow repo twice, side by side against different branches.
+- Actions that need to operate only against the root of the self repo, should expose a `path` input.
+
+#### Default value for `path` input
+
+The `path` input will default to `./` which is rooted against `github.workspace`.
+
+This default fits the mainline scenario well: single checkout
+
+For multi-checkout, users must specify the `path` input for at least one of the repositories.
+
+Note:
+- An alternative is for the self repo to default to `./` and other repos default to `<REPO_NAME>`. However nested layout is an atypical git layout and therefore is not a good default. Users should supply the path info.
+
+#### Example - Nested layout
+
+The following example checks-out two repositories and creates a nested layout.
+
+```yaml
+# Self repo - Checkout to $GITHUB_WORKSPACE
+- uses: checkout@v2
+
+# Other repo - Checkout to $GITHUB_WORKSPACE/myscripts
+- uses: checkout@v2
+  with:
+    repository: myorg/myscripts
+    path: myscripts
+```
+
+#### Example - Side by side layout
+
+The following example checks-out two repositories and creates a side-by-side layout.
+
+```yaml
+# Self repo - Checkout to $GITHUB_WORKSPACE/foo
+- uses: checkout@v2
+  with:
+    path: foo
+
+# Other repo - Checkout to $GITHUB_WORKSPACE/myscripts
+- uses: checkout@v2
+  with:
+    repository: myorg/myscripts
+    path: myscripts
+```
+
+#### Path impact to problem matchers
+
+Problem matchers associate the source files with annotations.
+
+Today the runner verifies the source file is under the `github.workspace`. Otherwise the source file property is dropped.
+
+Multi-checkout complicates the matter. However even today submodules may cause this heuristic to be inaccurate.
+
+A better solution is:
+
+Given a source file path, walk up the directories until the first `.git/config` is found. Check if it matches the self repo (`url = https://github.com/OWNER/REPO`). If not, drop the source file path.
+
+### Submodules
+
+With both PAT and SSH key support, we should be able to provide frictionless support for
+submodules scenarios: recursive, non-recursive, relative submodule paths.
+
+When fetching submodules, follow the `fetch-depth` settings.
+
+Also when fetching submodules, if the `ssh-key` input is not provided then convert SSH URLs to HTTPS: `-c url."https://github.com/".insteadOf "git@github.com:"`
+
+Credentials will be persisted in the submodules local git config too.
+
+### Port to typescript
+
+The checkout action should be a typescript action on the GitHub graph, for the following reasons:
+- Enables customers to fork the checkout repo and modify
+- Serves as an example for customers
+- Demystifies the checkout action manifest
+- Simplifies the runner
+- Reduce the amount of runner code to port (if we ever do)
+
+Note:
+- This means job-container images will need git in the PATH, for checkout.
+
+### Branching strategy and release tags
+
+- Create a servicing branch for V1: `releases/v1`
+- Merge the changes into `master`
+- Release using a new tag `preview`
+- When stable, release using a new tag `v2`
+
+## Consequences
+
+- Update the checkout action and readme
+- Update samples to consume `actions/checkout@v2`
+- Job containers now require git in the PATH for checkout, otherwise fallback to REST API
+- Minimum git version 2.18
+- Update problem matcher logic regarding source file verification (runner)

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "checkout",
-  "version": "2.0.0",
+  "version": "2.0.2",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -15,12 +15,28 @@
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     },
     "@actions/github": {
-      "version": "2.0.0",
+      "version": "2.2.0",
-      "resolved": "https://registry.npmjs.org/@actions/github/-/github-2.0.0.tgz",
+      "resolved": "https://registry.npmjs.org/@actions/github/-/github-2.2.0.tgz",
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       "requires": {
+        "@actions/http-client": "^1.0.3",
         "@octokit/graphql": "^4.3.1",
-        "@octokit/rest": "^16.15.0"
+        "@octokit/rest": "^16.43.1"
+      }
+    },
+    "@actions/http-client": {
+      "version": "1.0.8",
+      "resolved": "https://registry.npmjs.org/@actions/http-client/-/http-client-1.0.8.tgz",
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+      "requires": {
+        "tunnel": "0.0.6"
+      },
+      "dependencies": {
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+          "resolved": "https://registry.npmjs.org/tunnel/-/tunnel-0.0.6.tgz",
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+        }
       }
     },
     "@actions/io": {
@@ -597,14 +613,32 @@
         "@types/yargs": "^13.0.0"
       }
     },
-    "@octokit/endpoint": {
+    "@octokit/auth-token": {
-      "version": "5.5.1",
+      "version": "2.4.0",
-      "resolved": "https://registry.npmjs.org/@octokit/endpoint/-/endpoint-5.5.1.tgz",
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       "requires": {
-        "@octokit/types": "^2.0.0",
+        "@octokit/types": "^2.0.0"
+      }
+    },
+    "@octokit/endpoint": {
+      "version": "6.0.1",
+      "resolved": "https://registry.npmjs.org/@octokit/endpoint/-/endpoint-6.0.1.tgz",
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+      "requires": {
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         "is-plain-object": "^3.0.0",
-        "universal-user-agent": "^4.0.0"
+        "universal-user-agent": "^5.0.0"
+      },
+      "dependencies": {
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+          "version": "5.0.0",
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+          "requires": {
+            "os-name": "^3.1.0"
+          }
+        }
       }
     },
     "@octokit/graphql": {
@@ -617,25 +651,57 @@
         "universal-user-agent": "^4.0.0"
       }
     },
-    "@octokit/request": {
+    "@octokit/plugin-paginate-rest": {
-      "version": "5.3.1",
+      "version": "1.1.2",
-      "resolved": "https://registry.npmjs.org/@octokit/request/-/request-5.3.1.tgz",
+      "resolved": "https://registry.npmjs.org/@octokit/plugin-paginate-rest/-/plugin-paginate-rest-1.1.2.tgz",
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       "requires": {
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+        "@octokit/types": "^2.0.1"
-        "@octokit/request-error": "^1.0.1",
+      }
-        "@octokit/types": "^2.0.0",
+    },
+    "@octokit/plugin-request-log": {
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+    },
+    "@octokit/plugin-rest-endpoint-methods": {
+      "version": "2.4.0",
+      "resolved": "https://registry.npmjs.org/@octokit/plugin-rest-endpoint-methods/-/plugin-rest-endpoint-methods-2.4.0.tgz",
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+    "@octokit/request": {
+      "version": "5.4.2",
+      "resolved": "https://registry.npmjs.org/@octokit/request/-/request-5.4.2.tgz",
+      "integrity": "sha512-zKdnGuQ2TQ2vFk9VU8awFT4+EYf92Z/v3OlzRaSh4RIP0H6cvW1BFPXq4XYvNez+TPQjqN+0uSkCYnMFFhcFrw==",
+      "requires": {
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+        "@octokit/request-error": "^2.0.0",
+        "@octokit/types": "^2.11.1",
         "deprecation": "^2.0.0",
         "is-plain-object": "^3.0.0",
         "node-fetch": "^2.3.0",
         "once": "^1.4.0",
-        "universal-user-agent": "^4.0.0"
+        "universal-user-agent": "^5.0.0"
+      },
+      "dependencies": {
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+          "version": "5.0.0",
+          "resolved": "https://registry.npmjs.org/universal-user-agent/-/universal-user-agent-5.0.0.tgz",
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+          "requires": {
+            "os-name": "^3.1.0"
+          }
+        }
       }
     },
     "@octokit/request-error": {
-      "version": "1.2.0",
+      "version": "2.0.0",
-      "resolved": "https://registry.npmjs.org/@octokit/request-error/-/request-error-1.2.0.tgz",
+      "resolved": "https://registry.npmjs.org/@octokit/request-error/-/request-error-2.0.0.tgz",
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@@ -643,10 +709,14 @@
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     "@octokit/rest": {
-      "version": "16.35.0",
+      "version": "16.43.1",
-      "resolved": "https://registry.npmjs.org/@octokit/rest/-/rest-16.35.0.tgz",
+      "resolved": "https://registry.npmjs.org/@octokit/rest/-/rest-16.43.1.tgz",
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       "requires": {
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+        "@octokit/plugin-paginate-rest": "^1.1.1",
+        "@octokit/plugin-request-log": "^1.0.0",
+        "@octokit/plugin-rest-endpoint-methods": "2.4.0",
         "@octokit/request": "^5.2.0",
         "@octokit/request-error": "^1.0.2",
         "atob-lite": "^2.0.0",
@@ -659,12 +729,24 @@
         "octokit-pagination-methods": "^1.1.0",
         "once": "^1.4.0",
         "universal-user-agent": "^4.0.0"
+      },
+      "dependencies": {
+        "@octokit/request-error": {
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+          "requires": {
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+            "deprecation": "^2.0.0",
+            "once": "^1.4.0"
+          }
+        }
       }
     },
     "@octokit/types": {
-      "version": "2.0.2",
+      "version": "2.14.0",
-      "resolved": "https://registry.npmjs.org/@octokit/types/-/types-2.0.2.tgz",
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       "requires": {
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       }
@@ -6695,9 +6777,9 @@
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-      "version": "4.0.0",
+      "version": "4.0.1",
-      "resolved": "https://registry.npmjs.org/universal-user-agent/-/universal-user-agent-4.0.0.tgz",
+      "resolved": "https://registry.npmjs.org/universal-user-agent/-/universal-user-agent-4.0.1.tgz",
-      "integrity": "sha512-eM8knLpev67iBDizr/YtqkJsF3GK8gzDc6st/WKzrTuPtcsOKW/0IdL4cnMBsU69pOx0otavLWBDGTwg+dB0aA==",
+      "integrity": "sha512-LnST3ebHwVL2aNe4mejI9IQh2HfZ1RLo8Io2HugSif8ekzD1TlWpHpColOB/eh8JHMLkGH3Akqf040I+4ylNxg==",
       "requires": {
         "os-name": "^3.1.0"
       }
@@ -6876,9 +6958,9 @@
       "dev": true
     },
     "windows-release": {
-      "version": "3.2.0",
+      "version": "3.3.0",
-      "resolved": "https://registry.npmjs.org/windows-release/-/windows-release-3.2.0.tgz",
+      "resolved": "https://registry.npmjs.org/windows-release/-/windows-release-3.3.0.tgz",
-      "integrity": "sha512-QTlz2hKLrdqukrsapKsINzqMgOUpQW268eJ0OaOpJN32h272waxR9fkB9VoWRtK7uKHG5EHJcTXQBD8XZVJkFA==",
+      "integrity": "sha512-2HetyTg1Y+R+rUgrKeUEhAG/ZuOmTrI1NBb3ZyAGQMYmOJjBBPe4MTodghRkmLJZHwkuPi02anbeGP+Zf401LQ==",
       "requires": {
         "execa": "^1.0.0"
       }

package.json

@@ -1,17 +1,14 @@
 {
   "name": "checkout",
-  "version": "2.0.1",
+  "version": "2.0.2",
   "description": "checkout action",
   "main": "lib/main.js",
   "scripts": {
-    "build": "tsc",
+    "build": "tsc && ncc build && node lib/misc/generate-docs.js",
-    "format": "prettier --write **/*.ts",
+    "format": "prettier --write '**/*.ts'",
-    "format-check": "prettier --check **/*.ts",
+    "format-check": "prettier --check '**/*.ts'",
     "lint": "eslint src/**/*.ts",
-    "pack": "ncc build",
+    "test": "jest"
-    "gendocs": "node lib/misc/generate-docs.js",
-    "test": "jest",
-    "all": "npm run build && npm run format && npm run lint && npm run pack && npm run gendocs && npm test"
   },
   "repository": {
     "type": "git",
@@ -31,7 +28,7 @@
   "dependencies": {
     "@actions/core": "^1.1.3",
     "@actions/exec": "^1.0.1",
-    "@actions/github": "^2.0.0",
+    "@actions/github": "^2.2.0",
     "@actions/io": "^1.0.1",
     "@actions/tool-cache": "^1.1.2",
     "uuid": "^3.3.3"

src/git-auth-helper.ts

@@ -0,0 +1,350 @@
+import * as assert from 'assert'
+import * as core from '@actions/core'
+import * as exec from '@actions/exec'
+import * as fs from 'fs'
+import * as io from '@actions/io'
+import * as os from 'os'
+import * as path from 'path'
+import * as regexpHelper from './regexp-helper'
+import * as stateHelper from './state-helper'
+import * as urlHelper from './url-helper'
+import {default as uuid} from 'uuid/v4'
+import {IGitCommandManager} from './git-command-manager'
+import {IGitSourceSettings} from './git-source-settings'
+
+const IS_WINDOWS = process.platform === 'win32'
+const SSH_COMMAND_KEY = 'core.sshCommand'
+
+export interface IGitAuthHelper {
+  configureAuth(): Promise<void>
+  configureGlobalAuth(): Promise<void>
+  configureSubmoduleAuth(): Promise<void>
+  removeAuth(): Promise<void>
+  removeGlobalAuth(): Promise<void>
+}
+
+export function createAuthHelper(
+  git: IGitCommandManager,
+  settings?: IGitSourceSettings
+): IGitAuthHelper {
+  return new GitAuthHelper(git, settings)
+}
+
+class GitAuthHelper {
+  private readonly git: IGitCommandManager
+  private readonly settings: IGitSourceSettings
+  private readonly tokenConfigKey: string
+  private readonly tokenConfigValue: string
+  private readonly tokenPlaceholderConfigValue: string
+  private readonly insteadOfKey: string
+  private readonly insteadOfValue: string
+  private sshCommand = ''
+  private sshKeyPath = ''
+  private sshKnownHostsPath = ''
+  private temporaryHomePath = ''
+
+  constructor(
+    gitCommandManager: IGitCommandManager,
+    gitSourceSettings?: IGitSourceSettings
+  ) {
+    this.git = gitCommandManager
+    this.settings = gitSourceSettings || (({} as unknown) as IGitSourceSettings)
+
+    // Token auth header
+    const serverUrl = urlHelper.getServerUrl()
+    this.tokenConfigKey = `http.${serverUrl.origin}/.extraheader` // "origin" is SCHEME://HOSTNAME[:PORT]
+    const basicCredential = Buffer.from(
+      `x-access-token:${this.settings.authToken}`,
+      'utf8'
+    ).toString('base64')
+    core.setSecret(basicCredential)
+    this.tokenPlaceholderConfigValue = `AUTHORIZATION: basic ***`
+    this.tokenConfigValue = `AUTHORIZATION: basic ${basicCredential}`
+
+    // Instead of SSH URL
+    this.insteadOfKey = `url.${serverUrl.origin}/.insteadOf` // "origin" is SCHEME://HOSTNAME[:PORT]
+    this.insteadOfValue = `git@${serverUrl.hostname}:`
+  }
+
+  async configureAuth(): Promise<void> {
+    // Remove possible previous values
+    await this.removeAuth()
+
+    // Configure new values
+    await this.configureSsh()
+    await this.configureToken()
+  }
+
+  async configureGlobalAuth(): Promise<void> {
+    // Create a temp home directory
+    const runnerTemp = process.env['RUNNER_TEMP'] || ''
+    assert.ok(runnerTemp, 'RUNNER_TEMP is not defined')
+    const uniqueId = uuid()
+    this.temporaryHomePath = path.join(runnerTemp, uniqueId)
+    await fs.promises.mkdir(this.temporaryHomePath, {recursive: true})
+
+    // Copy the global git config
+    const gitConfigPath = path.join(
+      process.env['HOME'] || os.homedir(),
+      '.gitconfig'
+    )
+    const newGitConfigPath = path.join(this.temporaryHomePath, '.gitconfig')
+    let configExists = false
+    try {
+      await fs.promises.stat(gitConfigPath)
+      configExists = true
+    } catch (err) {
+      if (err.code !== 'ENOENT') {
+        throw err
+      }
+    }
+    if (configExists) {
+      core.info(`Copying '${gitConfigPath}' to '${newGitConfigPath}'`)
+      await io.cp(gitConfigPath, newGitConfigPath)
+    } else {
+      await fs.promises.writeFile(newGitConfigPath, '')
+    }
+
+    try {
+      // Override HOME
+      core.info(
+        `Temporarily overriding HOME='${this.temporaryHomePath}' before making global git config changes`
+      )
+      this.git.setEnvironmentVariable('HOME', this.temporaryHomePath)
+
+      // Configure the token
+      await this.configureToken(newGitConfigPath, true)
+
+      // Configure HTTPS instead of SSH
+      await this.git.tryConfigUnset(this.insteadOfKey, true)
+      if (!this.settings.sshKey) {
+        await this.git.config(this.insteadOfKey, this.insteadOfValue, true)
+      }
+    } catch (err) {
+      // Unset in case somehow written to the real global config
+      core.info(
+        'Encountered an error when attempting to configure token. Attempting unconfigure.'
+      )
+      await this.git.tryConfigUnset(this.tokenConfigKey, true)
+      throw err
+    }
+  }
+
+  async configureSubmoduleAuth(): Promise<void> {
+    // Remove possible previous HTTPS instead of SSH
+    await this.removeGitConfig(this.insteadOfKey, true)
+
+    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(
+        `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
+      const configPaths: string[] =
+        output.match(/(?<=(^|\n)file:)[^\t]+(?=\tremote\.origin\.url)/g) || []
+      for (const configPath of configPaths) {
+        core.debug(`Replacing token placeholder in '${configPath}'`)
+        this.replaceTokenPlaceholder(configPath)
+      }
+
+      if (this.settings.sshKey) {
+        // Configure core.sshCommand
+        await this.git.submoduleForeach(
+          `git config --local '${SSH_COMMAND_KEY}' '${this.sshCommand}'`,
+          this.settings.nestedSubmodules
+        )
+      } else {
+        // Configure HTTPS instead of SSH
+        await this.git.submoduleForeach(
+          `git config --local '${this.insteadOfKey}' '${this.insteadOfValue}'`,
+          this.settings.nestedSubmodules
+        )
+      }
+    }
+  }
+
+  async removeAuth(): Promise<void> {
+    await this.removeSsh()
+    await this.removeToken()
+  }
+
+  async removeGlobalAuth(): Promise<void> {
+    core.debug(`Unsetting HOME override`)
+    this.git.removeEnvironmentVariable('HOME')
+    await io.rmRF(this.temporaryHomePath)
+  }
+
+  private async configureSsh(): Promise<void> {
+    if (!this.settings.sshKey) {
+      return
+    }
+
+    // Write key
+    const runnerTemp = process.env['RUNNER_TEMP'] || ''
+    assert.ok(runnerTemp, 'RUNNER_TEMP is not defined')
+    const uniqueId = uuid()
+    this.sshKeyPath = path.join(runnerTemp, uniqueId)
+    stateHelper.setSshKeyPath(this.sshKeyPath)
+    await fs.promises.mkdir(runnerTemp, {recursive: true})
+    await fs.promises.writeFile(
+      this.sshKeyPath,
+      this.settings.sshKey.trim() + '\n',
+      {mode: 0o600}
+    )
+
+    // Remove inherited permissions on Windows
+    if (IS_WINDOWS) {
+      const icacls = await io.which('icacls.exe')
+      await exec.exec(
+        `"${icacls}" "${this.sshKeyPath}" /grant:r "${process.env['USERDOMAIN']}\\${process.env['USERNAME']}:F"`
+      )
+      await exec.exec(`"${icacls}" "${this.sshKeyPath}" /inheritance:r`)
+    }
+
+    // Write known hosts
+    const userKnownHostsPath = path.join(os.homedir(), '.ssh', 'known_hosts')
+    let userKnownHosts = ''
+    try {
+      userKnownHosts = (
+        await fs.promises.readFile(userKnownHostsPath)
+      ).toString()
+    } catch (err) {
+      if (err.code !== 'ENOENT') {
+        throw err
+      }
+    }
+    let knownHosts = ''
+    if (userKnownHosts) {
+      knownHosts += `# Begin from ${userKnownHostsPath}\n${userKnownHosts}\n# End from ${userKnownHostsPath}\n`
+    }
+    if (this.settings.sshKnownHosts) {
+      knownHosts += `# Begin from input known hosts\n${this.settings.sshKnownHosts}\n# end from input known hosts\n`
+    }
+    knownHosts += `# Begin implicitly added github.com\ngithub.com ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAq2A7hRGmdnm9tUDbO9IDSwBK6TbQa+PXYPCPy6rbTrTtw7PHkccKrpp0yVhp5HdEIcKr6pLlVDBfOLX9QUsyCOV0wzfjIJNlGEYsdlLJizHhbn2mUjvSAHQqZETYP81eFzLQNnPHt4EVVUh7VfDESU84KezmD5QlWpXLmvU31/yMf+Se8xhHTvKSCZIFImWwoG6mbUoWf9nzpIoaSjB+weqqUUmpaaasXVal72J+UX2B+2RPW3RcT0eOzQgqlJL3RKrTJvdsjE3JEAvGq3lGHSZXy28G3skua2SmVi/w4yCE6gbODqnTWlg7+wC604ydGXA8VJiS5ap43JXiUFFAaQ==\n# End implicitly added github.com\n`
+    this.sshKnownHostsPath = path.join(runnerTemp, `${uniqueId}_known_hosts`)
+    stateHelper.setSshKnownHostsPath(this.sshKnownHostsPath)
+    await fs.promises.writeFile(this.sshKnownHostsPath, knownHosts)
+
+    // Configure GIT_SSH_COMMAND
+    const sshPath = await io.which('ssh', true)
+    this.sshCommand = `"${sshPath}" -i "$RUNNER_TEMP/${path.basename(
+      this.sshKeyPath
+    )}"`
+    if (this.settings.sshStrict) {
+      this.sshCommand += ' -o StrictHostKeyChecking=yes -o CheckHostIP=no'
+    }
+    this.sshCommand += ` -o "UserKnownHostsFile=$RUNNER_TEMP/${path.basename(
+      this.sshKnownHostsPath
+    )}"`
+    core.info(`Temporarily overriding GIT_SSH_COMMAND=${this.sshCommand}`)
+    this.git.setEnvironmentVariable('GIT_SSH_COMMAND', this.sshCommand)
+
+    // Configure core.sshCommand
+    if (this.settings.persistCredentials) {
+      await this.git.config(SSH_COMMAND_KEY, this.sshCommand)
+    }
+  }
+
+  private async configureToken(
+    configPath?: string,
+    globalConfig?: boolean
+  ): Promise<void> {
+    // Validate args
+    assert.ok(
+      (configPath && globalConfig) || (!configPath && !globalConfig),
+      'Unexpected configureToken parameter combinations'
+    )
+
+    // 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
+    await this.git.config(
+      this.tokenConfigKey,
+      this.tokenPlaceholderConfigValue,
+      globalConfig
+    )
+
+    // 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()
+    const placeholderIndex = content.indexOf(this.tokenPlaceholderConfigValue)
+    if (
+      placeholderIndex < 0 ||
+      placeholderIndex != content.lastIndexOf(this.tokenPlaceholderConfigValue)
+    ) {
+      throw new Error(`Unable to replace auth placeholder in ${configPath}`)
+    }
+    assert.ok(this.tokenConfigValue, 'tokenConfigValue is not defined')
+    content = content.replace(
+      this.tokenPlaceholderConfigValue,
+      this.tokenConfigValue
+    )
+    await fs.promises.writeFile(configPath, content)
+  }
+
+  private async removeSsh(): Promise<void> {
+    // SSH key
+    const keyPath = this.sshKeyPath || stateHelper.SshKeyPath
+    if (keyPath) {
+      try {
+        await io.rmRF(keyPath)
+      } catch (err) {
+        core.debug(err.message)
+        core.warning(`Failed to remove SSH key '${keyPath}'`)
+      }
+    }
+
+    // SSH known hosts
+    const knownHostsPath =
+      this.sshKnownHostsPath || stateHelper.SshKnownHostsPath
+    if (knownHostsPath) {
+      try {
+        await io.rmRF(knownHostsPath)
+      } catch {
+        // Intentionally empty
+      }
+    }
+
+    // SSH command
+    await this.removeGitConfig(SSH_COMMAND_KEY)
+  }
+
+  private async removeToken(): Promise<void> {
+    // HTTP extra header
+    await this.removeGitConfig(this.tokenConfigKey)
+  }
+
+  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 '${configKey}' from the git config`)
+      }
+    }
+
+    const pattern = regexpHelper.escape(configKey)
+    await this.git.submoduleForeach(
+      `git config --local --name-only --get-regexp '${pattern}' && git config --local --unset-all '${configKey}' || :`,
+      true
+    )
+  }
+}

src/git-command-manager.ts

@@ -3,6 +3,8 @@ import * as exec from '@actions/exec'
 import * as fshelper from './fs-helper'
 import * as io from '@actions/io'
 import * as path from 'path'
+import * as refHelper from './ref-helper'
+import * as regexpHelper from './regexp-helper'
 import * as retryHelper from './retry-helper'
 import {GitVersion} from './git-version'
 
@@ -16,25 +18,37 @@ export interface IGitCommandManager {
   branchList(remote: boolean): Promise<string[]>
   checkout(ref: string, startPoint: string): Promise<void>
   checkoutDetach(): Promise<void>
-  config(configKey: string, configValue: string): Promise<void>
+  config(
-  configExists(configKey: string): Promise<boolean>
+    configKey: string,
-  fetch(fetchDepth: number, refSpec: string[]): Promise<void>
+    configValue: string,
+    globalConfig?: boolean
+  ): Promise<void>
+  configExists(configKey: string, globalConfig?: boolean): Promise<boolean>
+  fetch(refSpec: string[], fetchDepth?: number): Promise<void>
+  getDefaultBranch(repositoryUrl: string): Promise<string>
   getWorkingDirectory(): string
   init(): Promise<void>
   isDetached(): Promise<boolean>
   lfsFetch(ref: string): Promise<void>
   lfsInstall(): Promise<void>
-  log1(): Promise<void>
+  log1(): Promise<string>
   remoteAdd(remoteName: string, remoteUrl: string): Promise<void>
+  removeEnvironmentVariable(name: string): void
+  revParse(ref: string): Promise<string>
+  setEnvironmentVariable(name: string, value: string): void
+  shaExists(sha: string): Promise<boolean>
+  submoduleForeach(command: string, recursive: boolean): Promise<string>
+  submoduleSync(recursive: boolean): Promise<void>
+  submoduleUpdate(fetchDepth: number, recursive: boolean): Promise<void>
   tagExists(pattern: string): Promise<boolean>
   tryClean(): Promise<boolean>
-  tryConfigUnset(configKey: string): Promise<boolean>
+  tryConfigUnset(configKey: string, globalConfig?: boolean): Promise<boolean>
   tryDisableAutomaticGarbageCollection(): Promise<boolean>
   tryGetFetchUrl(): Promise<string>
   tryReset(): Promise<boolean>
 }
 
-export async function CreateCommandManager(
+export async function createCommandManager(
   workingDirectory: string,
   lfs: boolean
 ): Promise<IGitCommandManager> {
@@ -123,32 +137,45 @@ class GitCommandManager {
     await this.execGit(args)
   }
 
-  async config(configKey: string, configValue: string): Promise<void> {
+  async config(
-    await this.execGit(['config', '--local', configKey, configValue])
+    configKey: string,
+    configValue: string,
+    globalConfig?: boolean
+  ): Promise<void> {
+    await this.execGit([
+      'config',
+      globalConfig ? '--global' : '--local',
+      configKey,
+      configValue
+    ])
   }
 
-  async configExists(configKey: string): Promise<boolean> {
+  async configExists(
-    const pattern = configKey.replace(/[^a-zA-Z0-9_]/g, x => {
+    configKey: string,
-      return `\\${x}`
+    globalConfig?: boolean
-    })
+  ): Promise<boolean> {
+    const pattern = regexpHelper.escape(configKey)
     const output = await this.execGit(
-      ['config', '--local', '--name-only', '--get-regexp', pattern],
+      [
+        'config',
+        globalConfig ? '--global' : '--local',
+        '--name-only',
+        '--get-regexp',
+        pattern
+      ],
       true
     )
     return output.exitCode === 0
   }
 
-  async fetch(fetchDepth: number, refSpec: string[]): Promise<void> {
+  async fetch(refSpec: string[], fetchDepth?: number): Promise<void> {
-    const args = [
+    const args = ['-c', 'protocol.version=2', 'fetch']
-      '-c',
+    if (!refSpec.some(x => x === refHelper.tagsRefSpec)) {
-      'protocol.version=2',
+      args.push('--no-tags')
-      'fetch',
+    }
-      '--no-tags',
+
-      '--prune',
+    args.push('--prune', '--progress', '--no-recurse-submodules')
-      '--progress',
+    if (fetchDepth && fetchDepth > 0) {
-      '--no-recurse-submodules'
-    ]
-    if (fetchDepth > 0) {
       args.push(`--depth=${fetchDepth}`)
     } else if (
       fshelper.fileExistsSync(
@@ -169,6 +196,34 @@ class GitCommandManager {
     })
   }
 
+  async getDefaultBranch(repositoryUrl: string): Promise<string> {
+    let output: GitOutput | undefined
+    await retryHelper.execute(async () => {
+      output = await this.execGit([
+        'ls-remote',
+        '--quiet',
+        '--exit-code',
+        '--symref',
+        repositoryUrl,
+        'HEAD'
+      ])
+    })
+
+    if (output) {
+      // Satisfy compiler, will always be set
+      for (let line of output.stdout.trim().split('\n')) {
+        line = line.trim()
+        if (line.startsWith('ref:') || line.endsWith('HEAD')) {
+          return line
+            .substr('ref:'.length, line.length - 'ref:'.length - 'HEAD'.length)
+            .trim()
+        }
+      }
+    }
+
+    throw new Error('Unexpected output when retrieving default branch')
+  }
+
   getWorkingDirectory(): string {
     return this.workingDirectory
   }
@@ -199,14 +254,74 @@ class GitCommandManager {
     await this.execGit(['lfs', 'install', '--local'])
   }
 
-  async log1(): Promise<void> {
+  async log1(): Promise<string> {
-    await this.execGit(['log', '-1'])
+    const output = await this.execGit(['log', '-1'])
+    return output.stdout
   }
 
   async remoteAdd(remoteName: string, remoteUrl: string): Promise<void> {
     await this.execGit(['remote', 'add', remoteName, remoteUrl])
   }
 
+  removeEnvironmentVariable(name: string): void {
+    delete this.gitEnv[name]
+  }
+
+  /**
+   * Resolves a ref to a SHA. For a branch or lightweight tag, the commit SHA is returned.
+   * For an annotated tag, the tag SHA is returned.
+   * @param {string} ref  For example: 'refs/heads/master' or '/refs/tags/v1'
+   * @returns {Promise<string>}
+   */
+  async revParse(ref: string): Promise<string> {
+    const output = await this.execGit(['rev-parse', ref])
+    return output.stdout.trim()
+  }
+
+  setEnvironmentVariable(name: string, value: string): void {
+    this.gitEnv[name] = value
+  }
+
+  async shaExists(sha: string): Promise<boolean> {
+    const args = ['rev-parse', '--verify', '--quiet', `${sha}^{object}`]
+    const output = await this.execGit(args, true)
+    return output.exitCode === 0
+  }
+
+  async submoduleForeach(command: string, recursive: boolean): Promise<string> {
+    const args = ['submodule', 'foreach']
+    if (recursive) {
+      args.push('--recursive')
+    }
+    args.push(command)
+
+    const output = await this.execGit(args)
+    return output.stdout
+  }
+
+  async submoduleSync(recursive: boolean): Promise<void> {
+    const args = ['submodule', 'sync']
+    if (recursive) {
+      args.push('--recursive')
+    }
+
+    await this.execGit(args)
+  }
+
+  async submoduleUpdate(fetchDepth: number, recursive: boolean): Promise<void> {
+    const args = ['-c', 'protocol.version=2']
+    args.push('submodule', 'update', '--init', '--force')
+    if (fetchDepth > 0) {
+      args.push(`--depth=${fetchDepth}`)
+    }
+
+    if (recursive) {
+      args.push('--recursive')
+    }
+
+    await this.execGit(args)
+  }
+
   async tagExists(pattern: string): Promise<boolean> {
     const output = await this.execGit(['tag', '--list', pattern])
     return !!output.stdout.trim()
@@ -217,9 +332,17 @@ class GitCommandManager {
     return output.exitCode === 0
   }
 
-  async tryConfigUnset(configKey: string): Promise<boolean> {
+  async tryConfigUnset(
+    configKey: string,
+    globalConfig?: boolean
+  ): Promise<boolean> {
     const output = await this.execGit(
-      ['config', '--local', '--unset-all', configKey],
+      [
+        'config',
+        globalConfig ? '--global' : '--local',
+        '--unset-all',
+        configKey
+      ],
       true
     )
     return output.exitCode === 0

src/git-directory-helper.ts

@@ -0,0 +1,117 @@
+import * as assert from 'assert'
+import * as core from '@actions/core'
+import * as fs from 'fs'
+import * as fsHelper from './fs-helper'
+import * as io from '@actions/io'
+import * as path from 'path'
+import {IGitCommandManager} from './git-command-manager'
+
+export async function prepareExistingDirectory(
+  git: IGitCommandManager | undefined,
+  repositoryPath: string,
+  repositoryUrl: string,
+  clean: boolean,
+  ref: string
+): Promise<void> {
+  assert.ok(repositoryPath, 'Expected repositoryPath to be defined')
+  assert.ok(repositoryUrl, 'Expected repositoryUrl to be defined')
+
+  // Indicates whether to delete the directory contents
+  let remove = false
+
+  // Check whether using git or REST API
+  if (!git) {
+    remove = true
+  }
+  // Fetch URL does not match
+  else if (
+    !fsHelper.directoryExistsSync(path.join(repositoryPath, '.git')) ||
+    repositoryUrl !== (await git.tryGetFetchUrl())
+  ) {
+    remove = true
+  } else {
+    // Delete any index.lock and shallow.lock left by a previously canceled run or crashed git process
+    const lockPaths = [
+      path.join(repositoryPath, '.git', 'index.lock'),
+      path.join(repositoryPath, '.git', 'shallow.lock')
+    ]
+    for (const lockPath of lockPaths) {
+      try {
+        await io.rmRF(lockPath)
+      } catch (error) {
+        core.debug(`Unable to delete '${lockPath}'. ${error.message}`)
+      }
+    }
+
+    try {
+      core.startGroup('Removing previously created refs, to avoid conflicts')
+      // Checkout detached HEAD
+      if (!(await git.isDetached())) {
+        await git.checkoutDetach()
+      }
+
+      // Remove all refs/heads/*
+      let branches = await git.branchList(false)
+      for (const branch of branches) {
+        await git.branchDelete(false, branch)
+      }
+
+      // Remove any conflicting refs/remotes/origin/*
+      // Example 1: Consider ref is refs/heads/foo and previously fetched refs/remotes/origin/foo/bar
+      // Example 2: Consider ref is refs/heads/foo/bar and previously fetched refs/remotes/origin/foo
+      if (ref) {
+        ref = ref.startsWith('refs/') ? ref : `refs/heads/${ref}`
+        if (ref.startsWith('refs/heads/')) {
+          const upperName1 = ref.toUpperCase().substr('REFS/HEADS/'.length)
+          const upperName1Slash = `${upperName1}/`
+          branches = await git.branchList(true)
+          for (const branch of branches) {
+            const upperName2 = branch.substr('origin/'.length).toUpperCase()
+            const upperName2Slash = `${upperName2}/`
+            if (
+              upperName1.startsWith(upperName2Slash) ||
+              upperName2.startsWith(upperName1Slash)
+            ) {
+              await git.branchDelete(true, branch)
+            }
+          }
+        }
+      }
+      core.endGroup()
+
+      // Clean
+      if (clean) {
+        core.startGroup('Cleaning the repository')
+        if (!(await git.tryClean())) {
+          core.debug(
+            `The clean command failed. This might be caused by: 1) path too long, 2) permission issue, or 3) file in use. For futher investigation, manually run 'git clean -ffdx' on the directory '${repositoryPath}'.`
+          )
+          remove = true
+        } else if (!(await git.tryReset())) {
+          remove = true
+        }
+        core.endGroup()
+
+        if (remove) {
+          core.warning(
+            `Unable to clean or reset the repository. The repository will be recreated instead.`
+          )
+        }
+      }
+    } catch (error) {
+      core.warning(
+        `Unable to prepare the existing repository. The repository will be recreated instead.`
+      )
+      remove = true
+    }
+  }
+
+  if (remove) {
+    // Delete the contents of the directory. Don't delete the directory itself
+    // since it might be the current working directory.
+    core.info(`Deleting the contents of '${repositoryPath}'`)
+    for (const file of await fs.promises.readdir(repositoryPath)) {
+      await io.rmRF(path.join(repositoryPath, file))
+    }
+  }
+}

src/git-source-provider.ts

@@ -1,37 +1,23 @@
 import * as core from '@actions/core'
-import * as fs from 'fs'
 import * as fsHelper from './fs-helper'
+import * as gitAuthHelper from './git-auth-helper'
 import * as gitCommandManager from './git-command-manager'
+import * as gitDirectoryHelper from './git-directory-helper'
 import * as githubApiHelper from './github-api-helper'
 import * as io from '@actions/io'
 import * as path from 'path'
 import * as refHelper from './ref-helper'
 import * as stateHelper from './state-helper'
+import * as urlHelper from './url-helper'
 import {IGitCommandManager} from './git-command-manager'
+import {IGitSourceSettings} from './git-source-settings'
 
-const authConfigKey = `http.https://github.com/.extraheader`
+export async function getSource(settings: IGitSourceSettings): Promise<void> {
-
-export interface ISourceSettings {
-  repositoryPath: string
-  repositoryOwner: string
-  repositoryName: string
-  ref: string
-  commit: string
-  clean: boolean
-  fetchDepth: number
-  lfs: boolean
-  authToken: string
-  persistCredentials: boolean
-}
-
-export async function getSource(settings: ISourceSettings): Promise<void> {
   // Repository URL
   core.info(
     `Syncing repository: ${settings.repositoryOwner}/${settings.repositoryName}`
   )
-  const repositoryUrl = `https://github.com/${encodeURIComponent(
+  const repositoryUrl = urlHelper.getFetchUrl(settings)
-    settings.repositoryOwner
-  )}/${encodeURIComponent(settings.repositoryName)}`
 
   // Remove conflicting file path
   if (fsHelper.fileExistsSync(settings.repositoryPath)) {
@@ -46,15 +32,18 @@ export async function getSource(settings: ISourceSettings): Promise<void> {
   }
 
   // Git command manager
+  core.startGroup('Getting Git version info')
   const git = await getGitCommandManager(settings)
+  core.endGroup()
 
   // Prepare existing directory, otherwise recreate
   if (isExisting) {
-    await prepareExistingDirectory(
+    await gitDirectoryHelper.prepareExistingDirectory(
       git,
       settings.repositoryPath,
       repositoryUrl,
-      settings.clean
+      settings.clean,
+      settings.ref
     )
   }
 
@@ -64,6 +53,16 @@ export async function getSource(settings: ISourceSettings): Promise<void> {
     core.info(
       `To create a local Git repository instead, add Git ${gitCommandManager.MinimumGitVersion} or higher to the PATH`
     )
+    if (settings.submodules) {
+      throw new Error(
+        `Input 'submodules' not supported when falling back to download using the GitHub REST API. To create a local Git repository instead, add Git ${gitCommandManager.MinimumGitVersion} or higher to the PATH.`
+      )
+    } else if (settings.sshKey) {
+      throw new Error(
+        `Input 'ssh-key' not supported when falling back to download using the GitHub REST API. To create a local Git repository instead, add Git ${gitCommandManager.MinimumGitVersion} or higher to the PATH.`
+      )
+    }
+
     await githubApiHelper.downloadRepository(
       settings.authToken,
       settings.repositoryOwner,
@@ -72,90 +71,185 @@ export async function getSource(settings: ISourceSettings): Promise<void> {
       settings.commit,
       settings.repositoryPath
     )
-  } else {
+    return
-    // Save state for POST action
+  }
-    stateHelper.setRepositoryPath(settings.repositoryPath)
 
-    // Initialize the repository
+  // Save state for POST action
-    if (
+  stateHelper.setRepositoryPath(settings.repositoryPath)
-      !fsHelper.directoryExistsSync(path.join(settings.repositoryPath, '.git'))
-    ) {
-      await git.init()
-      await git.remoteAdd('origin', repositoryUrl)
-    }
 
-    // Disable automatic garbage collection
+  // Initialize the repository
-    if (!(await git.tryDisableAutomaticGarbageCollection())) {
+  if (
-      core.warning(
+    !fsHelper.directoryExistsSync(path.join(settings.repositoryPath, '.git'))
-        `Unable to turn off git automatic garbage collection. The git fetch operation may trigger garbage collection and cause a delay.`
+  ) {
-      )
+    core.startGroup('Initializing the repository')
-    }
+    await git.init()
+    await git.remoteAdd('origin', repositoryUrl)
+    core.endGroup()
+  }
 
-    // Remove possible previous extraheader
+  // Disable automatic garbage collection
-    await removeGitConfig(git, authConfigKey)
+  core.startGroup('Disabling automatic garbage collection')
+  if (!(await git.tryDisableAutomaticGarbageCollection())) {
+    core.warning(
+      `Unable to turn off git automatic garbage collection. The git fetch operation may trigger garbage collection and cause a delay.`
+    )
+  }
+  core.endGroup()
 
-    try {
+  const authHelper = gitAuthHelper.createAuthHelper(git, settings)
-      // Config auth token
+  try {
-      await configureAuthToken(git, settings.authToken)
+    // Configure auth
+    core.startGroup('Setting up auth')
+    await authHelper.configureAuth()
+    core.endGroup()
 
-      // LFS install
+    // Determine the default branch
-      if (settings.lfs) {
+    if (!settings.ref && !settings.commit) {
-        await git.lfsInstall()
+      core.startGroup('Determining the default branch')
+      if (settings.sshKey) {
+        settings.ref = await git.getDefaultBranch(repositoryUrl)
+      } else {
+        settings.ref = await githubApiHelper.getDefaultBranch(
+          settings.authToken,
+          settings.repositoryOwner,
+          settings.repositoryName
+        )
       }
+      core.endGroup()
+    }
 
-      // Fetch
+    // LFS install
-      const refSpec = refHelper.getRefSpec(settings.ref, settings.commit)
+    if (settings.lfs) {
-      await git.fetch(settings.fetchDepth, refSpec)
+      await git.lfsInstall()
+    }
 
-      // Checkout info
+    // Fetch
-      const checkoutInfo = await refHelper.getCheckoutInfo(
+    core.startGroup('Fetching the repository')
-        git,
+    if (settings.fetchDepth <= 0) {
+      // Fetch all branches and tags
+      let refSpec = refHelper.getRefSpecForAllHistory(
         settings.ref,
         settings.commit
       )
+      await git.fetch(refSpec)
 
-      // LFS fetch
+      // When all history is fetched, the ref we're interested in may have moved to a different
-      // Explicit lfs-fetch to avoid slow checkout (fetches one lfs object at a time).
+      // commit (push or force push). If so, fetch again with a targeted refspec.
-      // Explicit lfs fetch will fetch lfs objects in parallel.
+      if (!(await refHelper.testRef(git, settings.ref, settings.commit))) {
-      if (settings.lfs) {
+        refSpec = refHelper.getRefSpec(settings.ref, settings.commit)
-        await git.lfsFetch(checkoutInfo.startPoint || checkoutInfo.ref)
+        await git.fetch(refSpec)
       }
+    } else {
+      const refSpec = refHelper.getRefSpec(settings.ref, settings.commit)
+      await git.fetch(refSpec, settings.fetchDepth)
+    }
+    core.endGroup()
 
-      // Checkout
+    // Checkout info
-      await git.checkout(checkoutInfo.ref, checkoutInfo.startPoint)
+    core.startGroup('Determining the checkout info')
+    const checkoutInfo = await refHelper.getCheckoutInfo(
+      git,
+      settings.ref,
+      settings.commit
+    )
+    core.endGroup()
 
-      // Dump some info about the checked out commit
+    // LFS fetch
-      await git.log1()
+    // Explicit lfs-fetch to avoid slow checkout (fetches one lfs object at a time).
-    } finally {
+    // Explicit lfs fetch will fetch lfs objects in parallel.
-      if (!settings.persistCredentials) {
+    if (settings.lfs) {
-        await removeGitConfig(git, authConfigKey)
+      core.startGroup('Fetching LFS objects')
+      await git.lfsFetch(checkoutInfo.startPoint || checkoutInfo.ref)
+      core.endGroup()
+    }
+
+    // Checkout
+    core.startGroup('Checking out the ref')
+    await git.checkout(checkoutInfo.ref, checkoutInfo.startPoint)
+    core.endGroup()
+
+    // Submodules
+    if (settings.submodules) {
+      try {
+        // Temporarily override global config
+        core.startGroup('Setting up auth for fetching submodules')
+        await authHelper.configureGlobalAuth()
+        core.endGroup()
+
+        // Checkout submodules
+        core.startGroup('Fetching submodules')
+        await git.submoduleSync(settings.nestedSubmodules)
+        await git.submoduleUpdate(
+          settings.fetchDepth,
+          settings.nestedSubmodules
+        )
+        await git.submoduleForeach(
+          'git config --local gc.auto 0',
+          settings.nestedSubmodules
+        )
+        core.endGroup()
+
+        // Persist credentials
+        if (settings.persistCredentials) {
+          core.startGroup('Persisting credentials for submodules')
+          await authHelper.configureSubmoduleAuth()
+          core.endGroup()
+        }
+      } finally {
+        // Remove temporary global config override
+        await authHelper.removeGlobalAuth()
       }
     }
+
+    // Dump some info about the checked out commit
+    const commitInfo = await git.log1()
+
+    // Check for incorrect pull request merge commit
+    await refHelper.checkCommitInfo(
+      settings.authToken,
+      commitInfo,
+      settings.repositoryOwner,
+      settings.repositoryName,
+      settings.ref,
+      settings.commit
+    )
+  } finally {
+    // Remove auth
+    if (!settings.persistCredentials) {
+      core.startGroup('Removing auth')
+      await authHelper.removeAuth()
+      core.endGroup()
+    }
   }
 }
 
 export async function cleanup(repositoryPath: string): Promise<void> {
   // Repo exists?
-  if (!fsHelper.fileExistsSync(path.join(repositoryPath, '.git', 'config'))) {
+  if (
+    !repositoryPath ||
+    !fsHelper.fileExistsSync(path.join(repositoryPath, '.git', 'config'))
+  ) {
     return
   }
-  fsHelper.directoryExistsSync(repositoryPath, true)
 
-  // Remove the config key
+  let git: IGitCommandManager
-  const git = await gitCommandManager.CreateCommandManager(
+  try {
-    repositoryPath,
+    git = await gitCommandManager.createCommandManager(repositoryPath, false)
-    false
+  } catch {
-  )
+    return
-  await removeGitConfig(git, authConfigKey)
+  }
+
+  // Remove auth
+  const authHelper = gitAuthHelper.createAuthHelper(git)
+  await authHelper.removeAuth()
 }
 
 async function getGitCommandManager(
-  settings: ISourceSettings
+  settings: IGitSourceSettings
-): Promise<IGitCommandManager> {
+): Promise<IGitCommandManager | undefined> {
   core.info(`Working directory is '${settings.repositoryPath}'`)
-  let git = (null as unknown) as IGitCommandManager
   try {
-    return await gitCommandManager.CreateCommandManager(
+    return await gitCommandManager.createCommandManager(
       settings.repositoryPath,
       settings.lfs
     )
@@ -166,138 +260,6 @@ async function getGitCommandManager(
     }
 
     // Otherwise fallback to REST API
-    return (null as unknown) as IGitCommandManager
+    return undefined
-  }
-}
-
-async function prepareExistingDirectory(
-  git: IGitCommandManager,
-  repositoryPath: string,
-  repositoryUrl: string,
-  clean: boolean
-): Promise<void> {
-  let remove = false
-
-  // Check whether using git or REST API
-  if (!git) {
-    remove = true
-  }
-  // Fetch URL does not match
-  else if (
-    !fsHelper.directoryExistsSync(path.join(repositoryPath, '.git')) ||
-    repositoryUrl !== (await git.tryGetFetchUrl())
-  ) {
-    remove = true
-  } else {
-    // Delete any index.lock and shallow.lock left by a previously canceled run or crashed git process
-    const lockPaths = [
-      path.join(repositoryPath, '.git', 'index.lock'),
-      path.join(repositoryPath, '.git', 'shallow.lock')
-    ]
-    for (const lockPath of lockPaths) {
-      try {
-        await io.rmRF(lockPath)
-      } catch (error) {
-        core.debug(`Unable to delete '${lockPath}'. ${error.message}`)
-      }
-    }
-
-    try {
-      // Checkout detached HEAD
-      if (!(await git.isDetached())) {
-        await git.checkoutDetach()
-      }
-
-      // Remove all refs/heads/*
-      let branches = await git.branchList(false)
-      for (const branch of branches) {
-        await git.branchDelete(false, branch)
-      }
-
-      // Remove all refs/remotes/origin/* to avoid conflicts
-      branches = await git.branchList(true)
-      for (const branch of branches) {
-        await git.branchDelete(true, branch)
-      }
-
-      // Clean
-      if (clean) {
-        if (!(await git.tryClean())) {
-          core.debug(
-            `The clean command failed. This might be caused by: 1) path too long, 2) permission issue, or 3) file in use. For futher investigation, manually run 'git clean -ffdx' on the directory '${repositoryPath}'.`
-          )
-          remove = true
-        } else if (!(await git.tryReset())) {
-          remove = true
-        }
-
-        if (remove) {
-          core.warning(
-            `Unable to clean or reset the repository. The repository will be recreated instead.`
-          )
-        }
-      }
-    } catch (error) {
-      core.warning(
-        `Unable to prepare the existing repository. The repository will be recreated instead.`
-      )
-      remove = true
-    }
-  }
-
-  if (remove) {
-    // Delete the contents of the directory. Don't delete the directory itself
-    // since it might be the current working directory.
-    core.info(`Deleting the contents of '${repositoryPath}'`)
-    for (const file of await fs.promises.readdir(repositoryPath)) {
-      await io.rmRF(path.join(repositoryPath, file))
-    }
-  }
-}
-
-async function configureAuthToken(
-  git: IGitCommandManager,
-  authToken: string
-): Promise<void> {
-  // Configure a placeholder value. This approach avoids the credential being captured
-  // by process creation audit events, which are commonly logged. For more information,
-  // refer to https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/component-updates/command-line-process-auditing
-  const placeholder = `AUTHORIZATION: basic ***`
-  await git.config(authConfigKey, placeholder)
-
-  // Determine the basic credential value
-  const basicCredential = Buffer.from(
-    `x-access-token:${authToken}`,
-    'utf8'
-  ).toString('base64')
-  core.setSecret(basicCredential)
-
-  // Replace the value in the config file
-  const configPath = path.join(git.getWorkingDirectory(), '.git', 'config')
-  let content = (await fs.promises.readFile(configPath)).toString()
-  const placeholderIndex = content.indexOf(placeholder)
-  if (
-    placeholderIndex < 0 ||
-    placeholderIndex != content.lastIndexOf(placeholder)
-  ) {
-    throw new Error('Unable to replace auth placeholder in .git/config')
-  }
-  content = content.replace(
-    placeholder,
-    `AUTHORIZATION: basic ${basicCredential}`
-  )
-  await fs.promises.writeFile(configPath, content)
-}
-
-async function removeGitConfig(
-  git: IGitCommandManager,
-  configKey: string
-): Promise<void> {
-  if (
-    (await git.configExists(configKey)) &&
-    !(await git.tryConfigUnset(configKey))
-  ) {
-    // Load the config contents
-    core.warning(`Failed to remove '${configKey}' from the git config`)
   }
 }

src/git-source-settings.ts

@@ -0,0 +1,76 @@
+export interface IGitSourceSettings {
+  /**
+   * The location on disk where the repository will be placed
+   */
+  repositoryPath: string
+
+  /**
+   * The repository owner
+   */
+  repositoryOwner: string
+
+  /**
+   * The repository name
+   */
+  repositoryName: string
+
+  /**
+   * The ref to fetch
+   */
+  ref: string
+
+  /**
+   * The commit to checkout
+   */
+  commit: string
+
+  /**
+   * Indicates whether to clean the repository
+   */
+  clean: boolean
+
+  /**
+   * The depth when fetching
+   */
+  fetchDepth: number
+
+  /**
+   * Indicates whether to fetch LFS objects
+   */
+  lfs: boolean
+
+  /**
+   * Indicates whether to checkout submodules
+   */
+  submodules: boolean
+
+  /**
+   * Indicates whether to recursively checkout submodules
+   */
+  nestedSubmodules: boolean
+
+  /**
+   * The auth token to use when fetching the repository
+   */
+  authToken: string
+
+  /**
+   * The SSH key to configure
+   */
+  sshKey: string
+
+  /**
+   * Additional SSH known hosts
+   */
+  sshKnownHosts: string
+
+  /**
+   * Indicates whether the server must be a known host
+   */
+  sshStrict: boolean
+
+  /**
+   * Indicates whether to persist the credentials on disk to enable scripting authenticated git commands
+   */
+  persistCredentials: boolean
+}

src/github-api-helper.ts

@@ -7,7 +7,7 @@ import * as path from 'path'
 import * as retryHelper from './retry-helper'
 import * as toolCache from '@actions/tool-cache'
 import {default as uuid} from 'uuid/v4'
-import {ReposGetArchiveLinkParams} from '@octokit/rest'
+import {Octokit} from '@octokit/rest'
 
 const IS_WINDOWS = process.platform === 'win32'
 
@@ -19,6 +19,12 @@ export async function downloadRepository(
   commit: string,
   repositoryPath: string
 ): Promise<void> {
+  // Determine the default branch
+  if (!ref && !commit) {
+    core.info('Determining the default branch')
+    ref = await getDefaultBranch(authToken, owner, repo)
+  }
+
   // Download the archive
   let archiveData = await retryHelper.execute(async () => {
     core.info('Downloading the archive')
@@ -67,6 +73,46 @@ export async function downloadRepository(
   io.rmRF(extractPath)
 }
 
+/**
+ * Looks up the default branch name
+ */
+export async function getDefaultBranch(
+  authToken: string,
+  owner: string,
+  repo: string
+): Promise<string> {
+  return await retryHelper.execute(async () => {
+    core.info('Retrieving the default branch name')
+    const octokit = new github.GitHub(authToken)
+    let result: string
+    try {
+      // Get the default branch from the repo info
+      const response = await octokit.repos.get({owner, repo})
+      result = response.data.default_branch
+      assert.ok(result, 'default_branch cannot be empty')
+    } catch (err) {
+      // Handle .wiki repo
+      if (err['status'] === 404 && repo.toUpperCase().endsWith('.WIKI')) {
+        result = 'master'
+      }
+      // Otherwise error
+      else {
+        throw err
+      }
+    }
+
+    // Print the default branch
+    core.info(`Default branch '${result}'`)
+
+    // Prefix with 'refs/heads'
+    if (!result.startsWith('refs/')) {
+      result = `refs/heads/${result}`
+    }
+
+    return result
+  })
+}
+
 async function downloadArchive(
   authToken: string,
   owner: string,
@@ -75,7 +121,7 @@ async function downloadArchive(
   commit: string
 ): Promise<Buffer> {
   const octokit = new github.GitHub(authToken)
-  const params: ReposGetArchiveLinkParams = {
+  const params: Octokit.ReposGetArchiveLinkParams = {
     owner: owner,
     repo: repo,
     archive_format: IS_WINDOWS ? 'zipball' : 'tarball',

src/input-helper.ts

@@ -2,10 +2,10 @@ import * as core from '@actions/core'
 import * as fsHelper from './fs-helper'
 import * as github from '@actions/github'
 import * as path from 'path'
-import {ISourceSettings} from './git-source-provider'
+import {IGitSourceSettings} from './git-source-settings'
 
-export function getInputs(): ISourceSettings {
+export function getInputs(): IGitSourceSettings {
-  const result = ({} as unknown) as ISourceSettings
+  const result = ({} as unknown) as IGitSourceSettings
 
   // GitHub workspace
   let githubWorkspacePath = process.env['GITHUB_WORKSPACE']
@@ -61,10 +61,12 @@ export function getInputs(): ISourceSettings {
     if (isWorkflowRepository) {
       result.ref = github.context.ref
       result.commit = github.context.sha
-    }
 
-    if (!result.ref && !result.commit) {
+      // Some events have an unqualifed ref. For example when a PR is merged (pull_request closed event),
-      result.ref = 'refs/heads/master'
+      // the ref is unqualifed like "master" instead of "refs/heads/master".
+      if (result.commit && result.ref && !result.ref.startsWith('refs/')) {
+        result.ref = `refs/heads/${result.ref}`
+      }
     }
   }
   // SHA?
@@ -79,13 +81,6 @@ export function getInputs(): ISourceSettings {
   result.clean = (core.getInput('clean') || 'true').toUpperCase() === 'TRUE'
   core.debug(`clean = ${result.clean}`)
 
-  // Submodules
-  if (core.getInput('submodules')) {
-    throw new Error(
-      "The input 'submodules' is not supported in actions/checkout@v2"
-    )
-  }
-
   // Fetch depth
   result.fetchDepth = Math.floor(Number(core.getInput('fetch-depth') || '1'))
   if (isNaN(result.fetchDepth) || result.fetchDepth < 0) {
@@ -97,8 +92,27 @@ export function getInputs(): ISourceSettings {
   result.lfs = (core.getInput('lfs') || 'false').toUpperCase() === 'TRUE'
   core.debug(`lfs = ${result.lfs}`)
 
+  // Submodules
+  result.submodules = false
+  result.nestedSubmodules = false
+  const submodulesString = (core.getInput('submodules') || '').toUpperCase()
+  if (submodulesString == 'RECURSIVE') {
+    result.submodules = true
+    result.nestedSubmodules = true
+  } else if (submodulesString == 'TRUE') {
+    result.submodules = true
+  }
+  core.debug(`submodules = ${result.submodules}`)
+  core.debug(`recursive submodules = ${result.nestedSubmodules}`)
+
   // Auth token
-  result.authToken = core.getInput('token')
+  result.authToken = core.getInput('token', {required: true})
+
+  // SSH
+  result.sshKey = core.getInput('ssh-key')
+  result.sshKnownHosts = core.getInput('ssh-known-hosts')
+  result.sshStrict =
+    (core.getInput('ssh-strict') || 'true').toUpperCase() === 'TRUE'
 
   // Persist credentials
   result.persistCredentials =

src/misc/generate-docs.ts

@@ -59,13 +59,17 @@ function updateUsage(
 
     // Constrain the width of the description
     const width = 80
-    let description = input.description as string
+    let description = (input.description as string)
+      .trimRight()
+      .replace(/\r\n/g, '\n') // Convert CR to LF
+      .replace(/ +/g, ' ') //    Squash consecutive spaces
+      .replace(/ \n/g, '\n') //  Squash space followed by newline
     while (description) {
       // Longer than width? Find a space to break apart
       let segment: string = description
       if (description.length > width) {
         segment = description.substr(0, width + 1)
-        while (!segment.endsWith(' ') && segment) {
+        while (!segment.endsWith(' ') && !segment.endsWith('\n') && segment) {
           segment = segment.substr(0, segment.length - 1)
         }
 
@@ -77,15 +81,30 @@ function updateUsage(
         segment = description
       }
 
-      description = description.substr(segment.length) // Remaining
+      // Check for newline
-      segment = segment.trimRight() // Trim the trailing space
+      const newlineIndex = segment.indexOf('\n')
-      newReadme.push(`    # ${segment}`)
+      if (newlineIndex >= 0) {
+        segment = segment.substr(0, newlineIndex + 1)
+      }
+
+      // Append segment
+      newReadme.push(`    # ${segment}`.trimRight())
+
+      // Remaining
+      description = description.substr(segment.length)
     }
 
-    // Input and default
     if (input.default !== undefined) {
+      // Append blank line if description had paragraphs
+      if ((input.description as string).trimRight().match(/\n[ ]*\r?\n/)) {
+        newReadme.push(`    #`)
+      }
+
+      // Default
       newReadme.push(`    # Default: ${input.default}`)
     }
+
+    // Input name
     newReadme.push(`    ${key}: ''`)
 
     firstInput = false

src/ref-helper.ts

@@ -1,4 +1,9 @@
+import {URL} from 'url'
 import {IGitCommandManager} from './git-command-manager'
+import * as core from '@actions/core'
+import * as github from '@actions/github'
+
+export const tagsRefSpec = '+refs/tags/*:refs/tags/*'
 
 export interface ICheckoutInfo {
   ref: string
@@ -57,6 +62,16 @@ export async function getCheckoutInfo(
   return result
 }
 
+export function getRefSpecForAllHistory(ref: string, commit: string): string[] {
+  const result = ['+refs/heads/*:refs/remotes/origin/*', tagsRefSpec]
+  if (ref && ref.toUpperCase().startsWith('REFS/PULL/')) {
+    const branch = ref.substring('refs/pull/'.length)
+    result.push(`+${commit || ref}:refs/remotes/pull/${branch}`)
+  }
+
+  return result
+}
+
 export function getRefSpec(ref: string, commit: string): string[] {
   if (!ref && !commit) {
     throw new Error('Args ref and commit cannot both be empty')
@@ -107,3 +122,162 @@ export function getRefSpec(ref: string, commit: string): string[] {
     return [`+${ref}:${ref}`]
   }
 }
+
+/**
+ * Tests whether the initial fetch created the ref at the expected commit
+ */
+export async function testRef(
+  git: IGitCommandManager,
+  ref: string,
+  commit: string
+): Promise<boolean> {
+  if (!git) {
+    throw new Error('Arg git cannot be empty')
+  }
+
+  if (!ref && !commit) {
+    throw new Error('Args ref and commit cannot both be empty')
+  }
+
+  // No SHA? Nothing to test
+  if (!commit) {
+    return true
+  }
+  // SHA only?
+  else if (!ref) {
+    return await git.shaExists(commit)
+  }
+
+  const upperRef = ref.toUpperCase()
+
+  // refs/heads/
+  if (upperRef.startsWith('REFS/HEADS/')) {
+    const branch = ref.substring('refs/heads/'.length)
+    return (
+      (await git.branchExists(true, `origin/${branch}`)) &&
+      commit === (await git.revParse(`refs/remotes/origin/${branch}`))
+    )
+  }
+  // refs/pull/
+  else if (upperRef.startsWith('REFS/PULL/')) {
+    // Assume matches because fetched using the commit
+    return true
+  }
+  // refs/tags/
+  else if (upperRef.startsWith('REFS/TAGS/')) {
+    const tagName = ref.substring('refs/tags/'.length)
+    return (
+      (await git.tagExists(tagName)) && commit === (await git.revParse(ref))
+    )
+  }
+  // Unexpected
+  else {
+    core.debug(`Unexpected ref format '${ref}' when testing ref info`)
+    return true
+  }
+}
+
+export async function checkCommitInfo(
+  token: string,
+  commitInfo: string,
+  repositoryOwner: string,
+  repositoryName: string,
+  ref: string,
+  commit: string
+): Promise<void> {
+  try {
+    // GHES?
+    if (isGhes()) {
+      return
+    }
+
+    // Auth token?
+    if (!token) {
+      return
+    }
+
+    // Public PR synchronize, for workflow repo?
+    if (
+      fromPayload('repository.private') !== false ||
+      github.context.eventName !== 'pull_request' ||
+      fromPayload('action') !== 'synchronize' ||
+      repositoryOwner !== github.context.repo.owner ||
+      repositoryName !== github.context.repo.repo ||
+      ref !== github.context.ref ||
+      !ref.startsWith('refs/pull/') ||
+      commit !== github.context.sha
+    ) {
+      return
+    }
+
+    // Head SHA
+    const expectedHeadSha = fromPayload('after')
+    if (!expectedHeadSha) {
+      core.debug('Unable to determine head sha')
+      return
+    }
+
+    // Base SHA
+    const expectedBaseSha = fromPayload('pull_request.base.sha')
+    if (!expectedBaseSha) {
+      core.debug('Unable to determine base sha')
+      return
+    }
+
+    // Expected message?
+    const expectedMessage = `Merge ${expectedHeadSha} into ${expectedBaseSha}`
+    if (commitInfo.indexOf(expectedMessage) >= 0) {
+      return
+    }
+
+    // Extract details from message
+    const match = commitInfo.match(/Merge ([0-9a-f]{40}) into ([0-9a-f]{40})/)
+    if (!match) {
+      core.debug('Unexpected message format')
+      return
+    }
+
+    // Post telemetry
+    const actualHeadSha = match[1]
+    if (actualHeadSha !== expectedHeadSha) {
+      core.debug(
+        `Expected head sha ${expectedHeadSha}; actual head sha ${actualHeadSha}`
+      )
+      const octokit = new github.GitHub(token, {
+        userAgent: `actions-checkout-tracepoint/1.0 (code=STALE_MERGE;owner=${repositoryOwner};repo=${repositoryName};pr=${fromPayload(
+          'number'
+        )};run_id=${
+          process.env['GITHUB_RUN_ID']
+        };expected_head_sha=${expectedHeadSha};actual_head_sha=${actualHeadSha})`
+      })
+      await octokit.repos.get({owner: repositoryOwner, repo: repositoryName})
+    }
+  } catch (err) {
+    core.debug(`Error when validating commit info: ${err.stack}`)
+  }
+}
+
+function fromPayload(path: string): any {
+  return select(github.context.payload, path)
+}
+
+function select(obj: any, path: string): any {
+  if (!obj) {
+    return undefined
+  }
+
+  const i = path.indexOf('.')
+  if (i < 0) {
+    return obj[path]
+  }
+
+  const key = path.substr(0, i)
+  return select(obj[key], path.substr(i + 1))
+}
+
+function isGhes(): boolean {
+  const ghUrl = new URL(
+    process.env['GITHUB_SERVER_URL'] || 'https://github.com'
+  )
+  return ghUrl.hostname.toUpperCase() !== 'GITHUB.COM'
+}

src/regexp-helper.ts

@@ -0,0 +1,5 @@
+export function escape(value: string): string {
+  return value.replace(/[^a-zA-Z0-9_]/g, x => {
+    return `\\${x}`
+  })
+}

src/state-helper.ts

@@ -1,4 +1,3 @@
-import * as core from '@actions/core'
 import * as coreCommand from '@actions/core/lib/command'
 
 /**
@@ -12,6 +11,17 @@ export const IsPost = !!process.env['STATE_isPost']
 export const RepositoryPath =
   (process.env['STATE_repositoryPath'] as string) || ''
 
+/**
+ * The SSH key path for the POST action. The value is empty during the MAIN action.
+ */
+export const SshKeyPath = (process.env['STATE_sshKeyPath'] as string) || ''
+
+/**
+ * The SSH known hosts path for the POST action. The value is empty during the MAIN action.
+ */
+export const SshKnownHostsPath =
+  (process.env['STATE_sshKnownHostsPath'] as string) || ''
+
 /**
  * Save the repository path so the POST action can retrieve the value.
  */
@@ -23,6 +33,24 @@ export function setRepositoryPath(repositoryPath: string) {
   )
 }
 
+/**
+ * Save the SSH key path so the POST action can retrieve the value.
+ */
+export function setSshKeyPath(sshKeyPath: string) {
+  coreCommand.issueCommand('save-state', {name: 'sshKeyPath'}, sshKeyPath)
+}
+
+/**
+ * Save the SSH known hosts path so the POST action can retrieve the value.
+ */
+export function setSshKnownHostsPath(sshKnownHostsPath: string) {
+  coreCommand.issueCommand(
+    'save-state',
+    {name: 'sshKnownHostsPath'},
+    sshKnownHostsPath
+  )
+}
+
 // Publish a variable so that when the POST action runs, it can determine it should run the cleanup logic.
 // This is necessary since we don't have a separate entry point.
 if (!IsPost) {

src/url-helper.ts

@@ -0,0 +1,29 @@
+import * as assert from 'assert'
+import {IGitSourceSettings} from './git-source-settings'
+import {URL} from 'url'
+
+export function getFetchUrl(settings: IGitSourceSettings): string {
+  assert.ok(
+    settings.repositoryOwner,
+    'settings.repositoryOwner must be defined'
+  )
+  assert.ok(settings.repositoryName, 'settings.repositoryName must be defined')
+  const serviceUrl = getServerUrl()
+  const encodedOwner = encodeURIComponent(settings.repositoryOwner)
+  const encodedName = encodeURIComponent(settings.repositoryName)
+  if (settings.sshKey) {
+    return `git@${serviceUrl.hostname}:${encodedOwner}/${encodedName}.git`
+  }
+
+  // "origin" is SCHEME://HOSTNAME[:PORT]
+  return `${serviceUrl.origin}/${encodedOwner}/${encodedName}`
+}
+
+export function getServerUrl(): URL {
+  // todo: remove GITHUB_URL after support for GHES Alpha is no longer needed
+  return new URL(
+    process.env['GITHUB_SERVER_URL'] ||
+      process.env['GITHUB_URL'] ||
+      'https://github.com'
+  )
+}