PYTHON-714 Work around localhost exception issues in add_user when connected to MongoDB >= 2.7.1.

Author: Luke Lovett

pymongo/database.py

@@ -790,17 +790,20 @@ def add_user(self, name, password=None, read_only=None, **kwargs):
  try:
  uinfo = self.command("usersInfo", name,
  read_preference=ReadPreference.PRIMARY)
+ self._create_or_update_user(
+ (not uinfo["users"]), name, password, read_only, **kwargs)
  except OperationFailure, exc:
  # MongoDB >= 2.5.3 requires the use of commands to manage
  # users.
  if exc.code in common.COMMAND_NOT_FOUND_CODES:
  self._legacy_add_user(name, password, read_only, **kwargs)
- return
- raise
-
- # Create the user if not found in uinfo, otherwise update one.
- self._create_or_update_user(
- (not uinfo["users"]), name, password, read_only, **kwargs)
+ # Unauthorized. MongoDB >= 2.7.1 has a narrow localhost exception,
+ # and we must add a user before sending commands.
+ elif exc.code == 13:
+ self._create_or_update_user(
+ True, name, password, read_only, **kwargs)
+ else:
+ raise
 
  def remove_user(self, name):
  """Remove user `name` from this :class:`Database`.