fix(git): handle detached ref in shallow clone context

Signed-off-by: Emilien Escalle <[email protected]>

Author: neilime

__tests__/git.test.ts

@@ -141,6 +141,52 @@ describe('ref', () => {
     expect(ref).toEqual('refs/tags/8.0.0');
   });
 
+  it('returns mocked detached tag ref (shallow clone)', async () => {
+    jest.spyOn(Exec, 'getExecOutput').mockImplementation((cmd, args): Promise<ExecOutput> => {
+      const fullCmd = `${cmd} ${args?.join(' ')}`;
+      let result = '';
+      switch (fullCmd) {
+        case 'git branch --show-current':
+          result = '';
+          break;
+        case 'git show -s --pretty=%D':
+          result = 'grafted, HEAD, tag: 8.0.0';
+          break;
+      }
+      return Promise.resolve({
+        stdout: result,
+        stderr: '',
+        exitCode: 0
+      });
+    });
+
+    const ref = await Git.ref();
+
+    expect(ref).toEqual('refs/tags/8.0.0');
+  });
+
+  it('should throws an error when detached HEAD ref is not supported', async () => {
+    jest.spyOn(Exec, 'getExecOutput').mockImplementation((cmd, args): Promise<ExecOutput> => {
+      const fullCmd = `${cmd} ${args?.join(' ')}`;
+      let result = '';
+      switch (fullCmd) {
+        case 'git branch --show-current':
+          result = '';
+          break;
+        case 'git show -s --pretty=%D':
+          result = 'wrong, HEAD, tag: 8.0.0';
+          break;
+      }
+      return Promise.resolve({
+        stdout: result,
+        stderr: '',
+        exitCode: 0
+      });
+    });
+
+    await expect(Git.ref()).rejects.toThrow('Cannot find detached HEAD ref in "wrong, HEAD, tag: 8.0.0"');
+  });
+
   it('returns mocked detached branch ref', async () => {
     jest.spyOn(Exec, 'getExecOutput').mockImplementation((cmd, args): Promise<ExecOutput> => {
       const fullCmd = `${cmd} ${args?.join(' ')}`;

src/git.ts

@@ -123,13 +123,14 @@ export class Git {
   private static async getDetachedRef(): Promise<string> {
     const res = await Git.exec(['show', '-s', '--pretty=%D']);
 
-    const refMatch = res.match(/^HEAD, (.*)$/);
+    // Can be "HEAD, <tagname>" or "grafted, HEAD, <tagname>"
+    const refMatch = res.match(/^(grafted, )?HEAD, (.*)$/);
 
-    if (!refMatch) {
+    if (!refMatch || !refMatch[2]) {
       throw new Error(`Cannot find detached HEAD ref in "${res}"`);
     }
 
-    const ref = refMatch[1].trim();
+    const ref = refMatch[2].trim();
 
     // Tag refs are formatted as "tag: <tagname>"
     if (ref.startsWith('tag: ')) {