Merge branch 'stable'

* stable:
  Fixed race condition in 'repo sync -jN' that would open multiple masters.

git_config.py

@@ -18,6 +18,10 @@ import os
 import re
 import subprocess
 import sys
+try:
+  import threading as _threading
+except ImportError:
+  import dummy_threading as _threading
 import time
 import urllib2
 
@@ -371,10 +375,27 @@ class RefSpec(object):
 _master_processes = []
 _master_keys = set()
 _ssh_master = True
+_master_keys_lock = None
+
+def init_ssh():
+  """Should be called once at the start of repo to init ssh master handling.
+
+  At the moment, all we do is to create our lock.
+  """
+  global _master_keys_lock
+  assert _master_keys_lock is None, "Should only call init_ssh once"
+  _master_keys_lock = _threading.Lock()
 
 def _open_ssh(host, port=None):
   global _ssh_master
 
+  # Acquire the lock.  This is needed to prevent opening multiple masters for
+  # the same host when we're running "repo sync -jN" (for N > 1) _and_ the
+  # manifest <remote fetch="ssh://xyz"> specifies a different host from the
+  # one that was passed to repo init.
+  _master_keys_lock.acquire()
+  try:
+
     # Check to see whether we already think that the master is running; if we
     # think it's already running, return right away.
     if port is not None:
@@ -439,8 +460,12 @@ def _open_ssh(host, port=None):
     _master_keys.add(key)
     time.sleep(1)
     return True
+  finally:
+    _master_keys_lock.release()
 
 def close_ssh():
+  global _master_keys_lock
+
   terminate_ssh_clients()
 
   for p in _master_processes:
@@ -459,6 +484,9 @@ def close_ssh():
     except OSError:
       pass
 
+  # We're done with the lock, so we can delete it.
+  _master_keys_lock = None
+
 URI_SCP = re.compile(r'^([^@:]*@?[^:/]{1,}):')
 URI_ALL = re.compile(r'^([a-z][a-z+]*)://([^@/]*@?[^/]*)/')
 

main.py

@@ -28,7 +28,7 @@ import re
 import sys
 
 from trace import SetTrace
-from git_config import close_ssh
+from git_config import init_ssh, close_ssh
 from command import InteractiveCommand
 from command import MirrorSafeCommand
 from command import PagedCommand
@@ -212,6 +212,7 @@ def _Main(argv):
   repo = _Repo(opt.repodir)
   try:
     try:
+      init_ssh()
       repo._Run(argv)
     finally:
       close_ssh()