Error out of rebase-update if there are uncommitted changes

Currently, running rebase-update may lead to missing untracked files.
This change prints an error instead freezing and thawing local changes.

Bug: 1251047
Change-Id: Ia5f718ed957dae936d2ead2778760ae0c8d9f9ea
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3171828
Commit-Queue: Gavin Mak <gavinmak@google.com>
Reviewed-by: Josip Sokcevic <sokcevic@google.com>

git_rebase_update.py

@@ -256,12 +256,9 @@ def main(args=None):
   return_branch, return_workdir = find_return_branch_workdir()
   os.chdir(git.run('rev-parse', '--show-toplevel'))
 
-  if git.current_branch() == 'HEAD':
-    if git.run('status', '--porcelain'):
-      print('Cannot rebase-update with detached head + uncommitted changes.')
-      return 1
-  else:
-    git.freeze()  # just in case there are any local changes.
+  if git.run('status', '--porcelain'):
+    print('Cannot rebase-update with uncommitted changes.')
+    return 1
 
   branches_to_rebase = set(opts.branches)
   if opts.current:
@@ -322,7 +319,6 @@ def main(args=None):
     # return_branch may not be there any more.
     if return_branch in git.branches():
       git.run('checkout', return_branch)
-      git.thaw()
     else:
       root_branch = git.root()
       if return_branch != 'HEAD':

tests/git_rebase_update_test.py

@@ -105,6 +105,10 @@ class GitRebaseUpdateTest(git_test_utils.GitRepoReadWriteTestBase):
     self.repo.git('reset', '--hard', self.repo['A'])
     with self.repo.open('old_file', 'w') as f:
       f.write('old_files we want to keep around')
+
+    output, _ = self.repo.capture_stdio(self.reup.main)
+    self.assertIn('Cannot rebase-update', output)
+
     self.repo.git('add', 'old_file')
     self.repo.git_commit('old_file')
     self.repo.git('config', 'branch.old_branch.dormant', 'true')
@@ -121,12 +125,6 @@ class GitRebaseUpdateTest(git_test_utils.GitRepoReadWriteTestBase):
     self.assertEqual(self.repo['A'], self.origin['A'])
     self.assertEqual(self.repo['E'], self.origin['E'])
 
-    with self.repo.open('bob', 'wb') as f:
-      f.write(b'testing auto-freeze/thaw')
-
-    output, _ = self.repo.capture_stdio(self.reup.main)
-    self.assertIn('Cannot rebase-update', output)
-
     self.repo.run(self.nb.main, ['empty_branch'])
     self.repo.run(self.nb.main, ['--upstream-current', 'empty_branch2'])
 
@@ -160,11 +158,6 @@ class GitRebaseUpdateTest(git_test_utils.GitRepoReadWriteTestBase):
     self.assertIn('foobar up-to-date', output)
     self.assertIn('sub_K up-to-date', output)
 
-    with self.repo.open('bob') as f:
-      self.assertEqual(b'testing auto-freeze/thaw', f.read())
-
-    self.assertEqual(self.repo.git('status', '--porcelain').stdout, '?? bob\n')
-
     self.repo.git('checkout', 'origin/main')
     _, err = self.repo.capture_stdio(self.rp.main, [])
     self.assertIn('Must specify new parent somehow', err)
@@ -193,7 +186,6 @@ class GitRebaseUpdateTest(git_test_utils.GitRepoReadWriteTestBase):
     self.assertTrue(self.repo.run(self.gc.in_rebase))
 
     self.repo.git('rebase', '--abort')
-    self.assertIsNone(self.repo.run(self.gc.thaw))
 
     self.assertSchema("""
     A B C D E F G M N O foobar1 foobar2 H I J K L
@@ -202,8 +194,6 @@ class GitRebaseUpdateTest(git_test_utils.GitRepoReadWriteTestBase):
                                               K sub_K
     """)
 
-    self.assertEqual(self.repo.git('status', '--porcelain').stdout, '?? bob\n')
-
     branches = self.repo.run(set, self.gc.branches())
     self.assertEqual(branches, {'branch_K', 'main', 'sub_K', 'root_A',
                                 'branch_L', 'old_branch', 'foobar',
@@ -314,7 +304,6 @@ class GitRebaseUpdateTest(git_test_utils.GitRepoReadWriteTestBase):
     self.assertIn('could not be cleanly rebased:', output)
     self.assertIn('  branch_K', output)
 
-
   def testTrackTag(self):
     self.origin.git('tag', 'lkgr', self.origin['M'])
     self.repo.git('tag', 'lkgr', self.repo['D'])