PYTHON-1479 - Don't add projection to "find" cmd twice, 2

Author: ajdavis

pymongo/message.py

@@ -299,15 +299,11 @@ def get_message(self, set_slave_ok, sock_info, use_cmd=False):
 
  ns = _UJOIN % (self.db, self.coll)
  spec = self.spec
- if sock_info.is_mongos:
- spec = _maybe_add_read_preference(spec, self.read_preference)
 
  if use_cmd:
  ns = _UJOIN % (self.db, "$cmd")
  spec = self.as_command(sock_info)[0]
  ntoreturn = -1 # All DB commands return 1 document
- return query(flags, ns, self.ntoskip, ntoreturn,
- spec, None, self.codec_options)
  else:
  # OP_QUERY treats ntoreturn of -1 and 1 the same, return
  # one document and close the cursor. We have to use 2 for
@@ -318,8 +314,13 @@ def get_message(self, set_slave_ok, sock_info, use_cmd=False):
  ntoreturn = min(self.limit, ntoreturn)
  else:
  ntoreturn = self.limit
- return query(flags, ns, self.ntoskip, ntoreturn,
- spec, self.fields, self.codec_options)
+
+ if sock_info.is_mongos:
+ spec = _maybe_add_read_preference(spec,
+ self.read_preference)
+
+ return query(flags, ns, self.ntoskip, ntoreturn,
+ spec, None if use_cmd else self.fields, self.codec_options)
 
 
 class _GetMore(object):