README.md

@@ -8,7 +8,7 @@ Only a single commit is fetched by default, for the ref/SHA that triggered the w
 
 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.
 
-When Git 2.25 or higher is not in your PATH, falls back to the REST API to download the files.
+When Git 2.18 or higher is not in your PATH, falls back to the REST API to download the files.
 
 # What's new
 

__test__/git-command-manager.test.ts

@@ -24,7 +24,7 @@ describe('git-auth-helper tests', () => {
       console.log(args, options.listeners.stdout)
 
       if (args.includes('version')) {
-        options.listeners.stdout(Buffer.from('2.25'))
+        options.listeners.stdout(Buffer.from('2.18'))
         return 0
       }
 
@@ -57,7 +57,7 @@ describe('git-auth-helper tests', () => {
       console.log(args, options.listeners.stdout)
 
       if (args.includes('version')) {
-        options.listeners.stdout(Buffer.from('2.25'))
+        options.listeners.stdout(Buffer.from('2.18'))
         return 0
       }
 
@@ -97,7 +97,7 @@ describe('Test fetchDepth and fetchTags options', () => {
       console.log(args, options.listeners.stdout)
 
       if (args.includes('version')) {
-        options.listeners.stdout(Buffer.from('2.25'))
+        options.listeners.stdout(Buffer.from('2.18'))
       }
 
       return 0

dist/index.js

@@ -480,8 +480,7 @@ const retryHelper = __importStar(__nccwpck_require__(2155));
 const git_version_1 = __nccwpck_require__(3142);
 // Auth header not supported before 2.9
 // Wire protocol v2 not supported before 2.18
-// sparse-checkout not supported before 2.25
-exports.MinimumGitVersion = new git_version_1.GitVersion('2.25');
+exports.MinimumGitVersion = new git_version_1.GitVersion('2.18');
 function createCommandManager(workingDirectory, lfs, doSparseCheckout) {
     return __awaiter(this, void 0, void 0, function* () {
         return yield GitCommandManager.createCommandManager(workingDirectory, lfs, doSparseCheckout);
@@ -524,7 +523,13 @@ class GitCommandManager {
     branchList(remote) {
         return __awaiter(this, void 0, void 0, function* () {
             const result = [];
-            const args = ['rev-parse', '--symbolic'];
+            // Note, this implementation uses "rev-parse --symbolic-full-name" because the output from
+            // "branch --list" is more difficult when in a detached HEAD state.
+            // TODO(https://github.com/actions/checkout/issues/786): this implementation uses
+            // "rev-parse --symbolic-full-name" because there is a bug
+            // in Git 2.18 that causes "rev-parse --symbolic" to output symbolic full names. When
+            // 2.18 is no longer supported, we can switch back to --symbolic.
+            const args = ['rev-parse', '--symbolic-full-name'];
             if (remote) {
                 args.push('--remotes=origin');
             }

src/git-command-manager.ts

@@ -111,7 +111,16 @@ class GitCommandManager {
 
   async branchList(remote: boolean): Promise<string[]> {
     const result: string[] = []
-    const args = ['rev-parse', '--symbolic']
+
+    // Note, this implementation uses "rev-parse --symbolic-full-name" because the output from
+    // "branch --list" is more difficult when in a detached HEAD state.
+
+    // TODO(https://github.com/actions/checkout/issues/786): this implementation uses
+    // "rev-parse --symbolic-full-name" because there is a bug
+    // in Git 2.18 that causes "rev-parse --symbolic" to output symbolic full names. When
+    // 2.18 is no longer supported, we can switch back to --symbolic.
+
+    const args = ['rev-parse', '--symbolic-full-name']
     if (remote) {
       args.push('--remotes=origin')
     } else {