Running lots of sync processes in parallel can hit the failure:
Fetching projects: 23% (124/523)Exception in thread Thread-201:
Traceback (most recent call last):
File "/usr/lib/python2.7/threading.py", line 801, in __bootstrap_inner
self.run()
File "/usr/lib/python2.7/threading.py", line 754, in run
self.__target(*self.__args, **self.__kwargs)
File "/usr/local/src/repo/subcmds/sync.py", line 278, in _FetchProjectList
success = self._FetchHelper(opt, project, *args, **kwargs)
File "/usr/local/src/repo/subcmds/sync.py", line 357, in _FetchHelper
start, finish, success)
File "/usr/local/src/repo/event_log.py", line 104, in AddSync
event = self.Add(project.relpath, task_name, start, finish, success)
File "/usr/local/src/repo/event_log.py", line 74, in Add
'id': (kind, next(self._next_id)),
ValueError: generator already executing
It looks like, while we lock the multiprocessing value correctly, the
generator that wraps the value isn't parallel safe. Since we don't
have a way of doing that (as it's part of the language), turn it into
a plain function call instead.
Bug: https://crbug.com/gerrit/10293
Change-Id: I0db03601986ca0370a1699bab32adb03e7b2910a
