PYTHON-1033, PYTHON-1034 - Make protocol asserts exceptions

This change introduces a new exception, pymongo.errors.ProtocolError, and uses it in place of asserts related to the wire protocol.

Author: behackett

pymongo/errors.py

@@ -26,6 +26,10 @@ class PyMongoError(Exception):
  """Base class for all PyMongo exceptions."""
 
 
+class ProtocolError(PyMongoError):
+ """Raised for failures related to the wire protocol."""
+
+
 class ConnectionFailure(PyMongoError):
  """Raised when a connection to the database cannot be made or is lost."""
 

pymongo/helpers.py

@@ -28,6 +28,7 @@
  ExecutionTimeout,
  NotMasterError,
  OperationFailure,
+ ProtocolError,
  WriteError,
  WriteConcernError,
  WTimeoutError)
@@ -106,7 +107,8 @@ def _unpack_response(response, cursor_id=None, codec_options=CodecOptions()):
  response_flag = struct.unpack("<i", response[:4])[0]
  if response_flag & 1:
  # Shouldn't get this response if we aren't doing a getMore
- assert cursor_id is not None
+ if cursor_id is None:
+ raise ProtocolError("No cursor id for getMore operation")
 
  # Fake a getMore command response. OP_GET_MORE provides no document.
  msg = "Cursor not found, cursor id: %d" % (cursor_id,)

pymongo/network.py

@@ -32,7 +32,10 @@
 
 from pymongo import helpers, message
 from pymongo.common import MAX_MESSAGE_SIZE
-from pymongo.errors import AutoReconnect, NotMasterError, OperationFailure
+from pymongo.errors import (AutoReconnect,
+ NotMasterError,
+ OperationFailure,
+ ProtocolError)
 from pymongo.read_concern import DEFAULT_READ_CONCERN
 
 _UNPACK_INT = struct.Struct("<i").unpack
@@ -121,21 +124,21 @@ def receive_message(
  length = _UNPACK_INT(header[:4])[0]
 
  actual_op = _UNPACK_INT(header[12:])[0]
- assert operation == actual_op, ("wire protocol error: "
- "unknown opcode %r" % (actual_op,))
+ if operation != actual_op:
+ raise ProtocolError("Got opcode %r but expected "
+ "%r" % (actual_op, operation))
  # No request_id for exhaust cursor "getMore".
  if request_id is not None:
  response_id = _UNPACK_INT(header[8:12])[0]
- assert request_id == response_id, (
- "wire protocol error: got response id %r but expected %r"
- % (response_id, request_id))
-
- assert length > 16, ("wire protocol error: message length is shorter"
- " than standard message header: %r" % (length,))
-
- assert length <= max_message_size, (
- "wire protocol error: message length (%r) is larger than server max "
- "message size (%r)" % (length, max_message_size))
+ if request_id != response_id:
+ raise ProtocolError("Got response id %r but expected "
+ "%r" % (response_id, request_id))
+ if length <= 16:
+ raise ProtocolError("Message length (%r) not longer than standard "
+ "message header size (16)" % (length,))
+ if length > max_message_size:
+ raise ProtocolError("Message length (%r) is larger than server max "
+ "message size (%r)" % (length, max_message_size))
 
  return _receive_data_on_socket(sock, length - 16)