Add more error regexps for git retry

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 74 matching lines @@
 
     # crbug.com/187444
     r'RPC failed; result=\d+, HTTP code = \d+',
 
     # crbug.com/388876
     r'Connection timed out',
 
     # crbug.com/430343
     # TODO(dnj): Resync with Chromite.
     r'The requested URL returned error: 5\d+',
+
+    r'Connection reset by peer',
+
+    r'Unable to look up',
+
+    r'Couldn\'t resolve host',
+
+    r'fatal: bad object'

[dnj (Google), 2016/07/19 15:38:15]

I'm not sure that this is retriable. Couldn't this indicate a corrupt local
repository?

[dnj (Google), 2016/07/19 22:16:06]

(Please reply to comments inline, makes it easier to track)

After some research, this error can happen for any number of reasons, and has
been known to happen during remote and local operations. Because this is
potentially caused by local failure, it's best to leave it out of "git retry",
which needs to only handle transient errors.

 )
 
 GIT_TRANSIENT_ERRORS_RE = re.compile('|'.join(GIT_TRANSIENT_ERRORS),
                                      re.IGNORECASE)
 
 # git's for-each-ref command first supported the upstream:track token in its
 # format string in version 1.9.0, but some usages were broken until 2.3.0.
 # See git commit b6160d95 for more information.
 MIN_UPSTREAM_TRACK_GIT_VERSION = (2, 3)
 
@@ skipping 897 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))