fix(git): use branch-safe author names as username fallback (#25984)

Co-authored-by: Kyou0203 <kyou12138@gmail.com>

src/main/git/git-username.ts

@@ -326,7 +326,14 @@ export async function resolveLocalGitUsernameDetailed(
   }
   if (await localRepoHasEffectiveGitHubRemote(repoPath)) {
     const outcome = await getGhLoginOutcome()
-    return { username: outcome.login, authoritative: !outcome.timedOut }
+    if (outcome.login || outcome.timedOut) {
+      return { username: outcome.login, authoritative: !outcome.timedOut }
+    }
+  }
+  // Author names become prefixes only when they already form a safe branch component.
+  const authorName = (await readGitStdout(repoPath, ['config', '--get', 'user.name'])).trim()
+  if (isBranchSafeHostedLogin(authorName)) {
+    return { username: authorName, authoritative: true }
   }
   return { username: '', authoritative: true }
 }

src/main/git/repo-username.test.ts

@@ -148,7 +148,8 @@ describe('resolveLocalGitUsername', () => {
     expect(gitExecFileAsyncMock.mock.calls.map(([args]) => args)).toEqual([
       ['config', '--get', 'github.user'],
       ['config', '--get', 'user.username'],
-      ['remote']
+      ['remote'],
+      ['config', '--get', 'user.name']
     ])
     expect(ghExecFileAsyncMock).not.toHaveBeenCalled()
   })
@@ -197,16 +198,48 @@ describe('resolveLocalGitUsername', () => {
     expect(ghExecFileAsyncMock).toHaveBeenCalledTimes(1)
   })
 
-  it('does not derive GitHub username prefixes from non-GitHub remotes', async () => {
+  it('does not derive GitHub username prefixes from free-form author names on non-GitHub remotes', async () => {
     originRemoteUrl = 'https://gitlab.com/stablyai/orca.git'
     gitConfig['user.email'] = 'demo@example.com'
     gitConfig['user.name'] = 'Demo User'
     ghExecFileAsyncMock.mockResolvedValueOnce({ stdout: 'gh-demo\n', stderr: '' })
 
+    // Spaces make "Demo User" branch-unsafe; free-form author identity stays out of prefixes.
     await expect(resolveLocalGitUsername('/repo')).resolves.toBe('')
     expect(ghExecFileAsyncMock).not.toHaveBeenCalled()
   })
 
+  it('falls back to branch-safe user.name when github.user and gh login are absent', async () => {
+    // Issue #11590: only `user.name = lorengroves` is configured; branch prefix was empty.
+    originRemoteUrl = 'https://github.com/stablyai/orca.git'
+    gitConfig['user.name'] = 'lorengroves'
+    ghExecFileAsyncMock.mockRejectedValue(makeExecError('gh unavailable'))
+
+    await expect(resolveLocalGitUsername('/repo')).resolves.toBe('lorengroves')
+  })
+
+  it('uses branch-safe user.name on non-GitHub remotes when no explicit username keys exist', async () => {
+    originRemoteUrl = 'https://gitlab.com/stablyai/orca.git'
+    gitConfig['user.name'] = 'lorengroves'
+    ghExecFileAsyncMock.mockResolvedValueOnce({ stdout: 'gh-demo\n', stderr: '' })
+
+    await expect(resolveLocalGitUsername('/repo')).resolves.toBe('lorengroves')
+    expect(ghExecFileAsyncMock).not.toHaveBeenCalled()
+  })
+
+  it.each([
+    'person@example.com',
+    '42+person',
+    'person..name',
+    'person.lock',
+    'person\\name',
+    'person/name'
+  ])('does not rewrite or accept unsafe author name %s', async (authorName) => {
+    originRemoteUrl = 'https://gitlab.com/stablyai/orca.git'
+    gitConfig['user.name'] = authorName
+    await expect(resolveLocalGitUsername('/repo')).resolves.toBe('')
+  })
+
   it('ignores a secondary GitHub mirror when the effective remote is GitLab', async () => {
     // Why: a GitLab-primary repo with a GitHub mirror must not pick up the
     // GitHub account name as its branch prefix — only the effective remote