Check for detached HEAD state.

Bug: 1416683
Change-Id: I538715d05170662001ac7193a86dbd2e7f50e3f2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4258505
Reviewed-by: Josip Sokcevic <sokcevic@chromium.org>
Commit-Queue: Josip Sokcevic <sokcevic@chromium.org>
Auto-Submit: Joanna Wang <jojwang@chromium.org>

git_cl.py

@@ -4908,6 +4908,10 @@ def _UploadAllPrecheck(options, orig_args):
       since their last upload and a boolean of whether the user wants to
       cherry-pick and upload the current branch instead of uploading all cls.
   """
+  cl = Changelist()
+  if cl.GetBranch() is None:
+    DieWithError('Can\'t upload from detached HEAD state. Get on a branch!')
+
   branch_ref = None
   cls = []
   must_upload_upstream = False

tests/git_cl_test.py

@@ -1692,7 +1692,9 @@ class TestGitCl(unittest.TestCase):
         'current', 'upstream3', 'blank3', 'blank2', 'upstream2', 'blank1',
         'upstream1', 'origin/main'
     ]
-    mockGetBranchRef.side_effect = ['refs/heads/%s' % b for b in branches]
+    mockGetBranchRef.side_effect = (
+        ['refs/heads/current'] +  # detached HEAD check
+        ['refs/heads/%s' % b for b in branches])
     mockGetCommonAncestorWithUpstream.side_effect = [
         'commit3.5',
         'commit3.5',
@@ -1808,7 +1810,9 @@ class TestGitCl(unittest.TestCase):
 
     mockGetRemoteBranch.return_value = ('origin', 'refs/remotes/origin/main')
     branches = ['current', 'upstream3', 'main']
-    mockGetBranchRef.side_effect = ['refs/heads/%s' % b for b in branches]
+    mockGetBranchRef.side_effect = (
+        ['refs/heads/current'] +  # detached HEAD check
+        ['refs/heads/%s' % b for b in branches])
 
     mockGetCommonAncestorWithUpstream.side_effect = ['commit3.5', 'commit0.5']
     mockFetchUpstreamTuple.side_effect = [('.', 'refs/heads/upstream3'),
@@ -1864,7 +1868,12 @@ class TestGitCl(unittest.TestCase):
     orig_args = ['--preserve-tryjobs', '--chicken']
 
     mockGetRemoteBranch.return_value = ('origin', 'refs/remotes/origin/main')
-    mockGetBranchRef.side_effect = ['refs/heads/current', 'refs/heads/main']
+    mockGetBranchRef.side_effect = [
+        'refs/heads/current',  # detached HEAD check
+        'refs/heads/current',  # call within while loop
+        'refs/heads/main',
+        'refs/heads/main'
+    ]
     mockGetCommonAncestorWithUpstream.return_value = 'commit3.5'
     mockFetchUpstreamTuple.return_value = ('', 'refs/heads/main')
     mockIsAncestor.return_value = True
@@ -1889,6 +1898,12 @@ class TestGitCl(unittest.TestCase):
     with self.assertRaises(SystemExitMock):
       git_cl._UploadAllPrecheck(options, orig_args)
 
+  @mock.patch('scm.GIT.GetBranchRef', return_value=None)
+  def test_upload_all_precheck_detached_HEAD(self, mockGetBranchRef):
+
+    with self.assertRaises(SystemExitMock):
+      git_cl._UploadAllPrecheck(optparse.Values(), [])
+
   @mock.patch('git_cl.RunGit')
   @mock.patch('git_cl.CMDupload')
   @mock.patch('sys.stdin', StringIO('\n'))