Added SafeRename to better handle problems with git processes locking directories.

gclient_utils.py

Index: gclient_utils.py
diff --git a/gclient_utils.py b/gclient_utils.py
index 8385deb054a8b6823f13b5cfeef4816f45999304..45494dd0304fd47dee24d52975de63f962856009 100644
--- a/gclient_utils.py
+++ b/gclient_utils.py
@@ -96,6 +96,31 @@ def FileWrite(filename, content, mode='w'):
     f.write(content)
 
 
+def SafeRename(old, new):

[M-A Ruel, 2013/09/18 18:36:16]

Use safe_rename instead, we're slowly moving to non camelcase naming.

[karmann, 2013/09/20 03:35:30]

Done.

+  """

[M-A Ruel, 2013/09/18 18:36:16]

"""Renames a file reliably.

[karmann, 2013/09/20 03:35:30]

Done.

+  Renames a file reliably.
+
+  Sometimes os.rename does not work because a dying git process keeps a handle 
+  on it for a few seconds. An exception is then thrown, which make the program 
+  give up what it was doing and remove what was deleted.
+  The only solution is to catch the exception and try again until it works. 
+  """
+  count = 0

[M-A Ruel, 2013/09/18 18:36:16]

# Roughly 10s
retries = 100
for i in range(retries):
  try:
    os.rename(old, new)
    break
  except OSError:
    if i == (retries - 1):
      raise
    logging.debug(...
    time.sleep(0.1)

[karmann, 2013/09/20 03:35:30]

Done.

+  while 1:
+    count += 1
+    try:
+      os.rename(old, new)
+      logging.debug("Renamed %s in %s" % (old, new))
+      break
+    except OSError:
+      if count > 15:
+        # Give up.
+        raise
+      # retry
+      logging.debug("Renaming failed from %s to %s. Retrying ..." % (old, new))
+      time.sleep(1)
+
+
 def rmtree(path):
   """shutil.rmtree() on steroids.