Better error checking in git freeze

git_common.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Monkeypatch IMapIterator so that Ctrl-C can kill everything properly.
 # Derived from https://gist.github.com/aljungberg/626518
 import multiprocessing.pool
 from multiprocessing.pool import IMapIterator
 def wrapper(func):
   def wrap(self, timeout=None):
@@ skipping 410 matching lines @@
             git config %s <new_limit>
           Where <new_limit> is an integer threshold in megabytes.""",
           untracked_size, limit_mb, key)
 
   try:
     run('commit', '--no-verify', '-m', FREEZE + '.indexed')
     took_action = True
   except subprocess2.CalledProcessError:
     pass
 
+  add_errors = False
   try:
-    run('add', '-A')
+    run('add', '-A', '--ignore-errors')
+  except subprocess2.CalledProcessError:
+    add_errors = True
+
+  try:
     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():
   """Get the dictionary of {branch: parent}, compatible with topo_iter.
 
   Returns a tuple of (skipped, <branch_tree dict>) where skipped is a set of
   branches without upstream branches defined.
   """
   skipped = set()
   branch_tree = {}
@@ skipping 545 matching lines @@
                       ['HEAD'])
 
 
 def clone_file(repository, new_workdir, link, operation):
   if not os.path.exists(os.path.join(repository, link)):
     return
   link_dir = os.path.dirname(os.path.join(new_workdir, link))
   if not os.path.exists(link_dir):
     os.makedirs(link_dir)
   operation(os.path.join(repository, link), os.path.join(new_workdir, link))