event_log: turn id generation from a generator to a func call

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

.pydevproject

@@ -5,6 +5,6 @@
 <pydev_pathproperty name="org.python.pydev.PROJECT_SOURCE_PATH">
 <path>/git-repo</path>
 </pydev_pathproperty>
-<pydev_property name="org.python.pydev.PYTHON_PROJECT_VERSION">python 2.6</pydev_property>
+<pydev_property name="org.python.pydev.PYTHON_PROJECT_VERSION">python 2.7</pydev_property>
 <pydev_property name="org.python.pydev.PYTHON_PROJECT_INTERPRETER">Default</pydev_property>
 </pydev_project>

README.md

@@ -7,7 +7,7 @@ easier to work with Git.  The repo command is an executable Python script
 that you can put anywhere in your path.
 
 * Homepage: https://gerrit.googlesource.com/git-repo/
-* Bug reports: https://code.google.com/p/git-repo/issues/
+* Bug reports: https://bugs.chromium.org/p/gerrit/issues/list?q=component:repo
 * Source: https://gerrit.googlesource.com/git-repo/
 * Overview: https://source.android.com/source/developing.html
 * Docs: https://source.android.com/source/using-repo.html

event_log.py

@@ -18,8 +18,6 @@ from __future__ import print_function
 import json
 import multiprocessing
 
-from pyversion import is_python3
-
 TASK_COMMAND = 'command'
 TASK_SYNC_NETWORK = 'sync-network'
 TASK_SYNC_LOCAL = 'sync-local'
@@ -53,7 +51,6 @@ class EventLog(object):
   def __init__(self):
     """Initializes the event log."""
     self._log = []
-    self._next_id = _EventIdGenerator()
     self._parent = None
 
   def Add(self, name, task_name, start, finish=None, success=None,
@@ -73,7 +70,7 @@ class EventLog(object):
       A dictionary of the event added to the log.
     """
     event = {
-        'id': (kind, self._next_id.__next__() if is_python3() else self._next_id.next()),
+        'id': (kind, _NextEventId()),
         'name': name,
         'task_name': task_name,
         'start_time': start,
@@ -164,16 +161,16 @@ class EventLog(object):
         f.write('\n')
 
 
-def _EventIdGenerator():
-  """Returns multi-process safe iterator that generates locally unique id.
+# An integer id that is unique across this invocation of the program.
+_EVENT_ID = multiprocessing.Value('i', 1)
 
-  Yields:
+def _NextEventId():
+  """Helper function for grabbing the next unique id.
+
+  Returns:
     A unique, to this invocation of the program, integer id.
   """
-  eid = multiprocessing.Value('i', 1)
-
-  while True:
-    with eid.get_lock():
-      val = eid.value
-      eid.value += 1
-    yield val
+  with _EVENT_ID.get_lock():
+    val = _EVENT_ID.value
+    _EVENT_ID.value += 1
+  return val

repo

@@ -23,7 +23,7 @@ REPO_REV = 'stable'
 # limitations under the License.
 
 # increment this whenever we make important changes to this script
-VERSION = (1, 24)
+VERSION = (1, 25)
 
 # increment this if the MAINTAINER_KEYS block is modified
 KEYRING_VERSION = (1, 2)
@@ -113,7 +113,7 @@ repodir = '.repo'                # name of repo's private directory
 S_repo = 'repo'                  # special repo repository
 S_manifests = 'manifests'        # special manifest repository
 REPO_MAIN = S_repo + '/main.py'  # main script
-MIN_PYTHON_VERSION = (2, 6)      # minimum supported python version
+MIN_PYTHON_VERSION = (2, 7)      # minimum supported python version
 GITC_CONFIG_FILE = '/gitc/.config'
 GITC_FS_ROOT_DIR = '/gitc/manifest-rw/'
 
@@ -152,9 +152,12 @@ def _print(*objects, **kwargs):
 # Python version check
 ver = sys.version_info
 if (ver[0], ver[1]) < MIN_PYTHON_VERSION:
-  _print('error: Python version %s unsupported.\n'
-         'Please use Python 2.6 - 2.7 instead.'
-         % sys.version.split(' ')[0], file=sys.stderr)
+  _print('error: Python version {} unsupported.\n'
+         'Please use Python {}.{} instead.'.format(
+             sys.version.split(' ')[0],
+             MIN_PYTHON_VERSION[0],
+             MIN_PYTHON_VERSION[1],
+         ), file=sys.stderr)
   sys.exit(1)
 
 home_dot_repo = os.path.expanduser('~/.repoconfig')
@@ -180,7 +183,7 @@ group.add_option('-b', '--manifest-branch',
 group.add_option('-m', '--manifest-name',
                  dest='manifest_name',
                  help='initial manifest file', metavar='NAME.xml')
-group.add_option('-c', '--current-branch',
+group.add_option('--current-branch',
                  dest='current_branch_only', action='store_true',
                  help='fetch only current manifest branch from server')
 group.add_option('--mirror',
@@ -909,6 +912,6 @@ def main(orig_args):
 if __name__ == '__main__':
   if ver[0] == 3:
     _print('warning: Python 3 support is currently experimental. YMMV.\n'
-           'Please use Python 2.6 - 2.7 instead.',
+           'Please use Python 2.7 instead.',
            file=sys.stderr)
   main(sys.argv[1:])

subcmds/init.py

@@ -95,7 +95,7 @@ to update the working directory files.
     g.add_option('-b', '--manifest-branch',
                  dest='manifest_branch',
                  help='manifest branch or revision', metavar='REVISION')
-    g.add_option('-c', '--current-branch',
+    g.add_option('--current-branch',
                  dest='current_branch_only', action='store_true',
                  help='fetch only current manifest branch from server')
     g.add_option('-m', '--manifest-name',