Better error checking in git freeze

R=iannucci@chromium.org
BUG=567157

Review-Url: https://codereview.chromium.org/1527403002

git_common.py

@@ -431,15 +431,24 @@ def freeze():
   except subprocess2.CalledProcessError:
     pass
 
+  add_errors = False
+  try:
+    run('add', '-A', '--ignore-errors')
+  except subprocess2.CalledProcessError:
+    add_errors = True
+
   try:
-    run('add', '-A')
     run('commit', '--no-verify', '-m', FREEZE + '.unindexed')
     took_action = True
   except subprocess2.CalledProcessError:
     pass
 
+  ret = []
+  if add_errors:
+    ret.append('Failed to index some unindexed files.')
   if not took_action:
-    return 'Nothing to freeze.'
+    ret.append('Nothing to freeze.')
+  return ' '.join(ret) or None
 
 
 def get_branch_tree():

tests/git_common_test.py

@@ -872,6 +872,17 @@ class GitFreezeThaw(git_test_utils.GitRepoReadWriteTestBase):
 
     self.repo.run(inner)
 
+  def testAddError(self):
+    def inner():
+      self.repo.git('checkout', '-b', 'unreadable_file_branch')
+      with open('bad_file', 'w') as f:
+        f.write('some text')
+      os.chmod('bad_file', 0111)
+      ret = self.repo.run(self.gc.freeze)
+      self.assertIn('Failed to index some unindexed files.', ret)
+
+    self.repo.run(inner)
+
 
 class GitMakeWorkdir(git_test_utils.GitRepoReadOnlyTestBase, GitCommonTestBase):
   def setUp(self):