Down-integrate from internal branch

22 files changed, 2003 insertions, 94 deletions

diff --git a/python/google/protobuf/internal/api_implementation.py b/python/google/protobuf/internal/api_implementation.py
index b3e412e2..ce02a329 100755
--- a/python/google/protobuf/internal/api_implementation.py
+++ b/python/google/protobuf/internal/api_implementation.py
@@ -56,9 +56,32 @@ if _implementation_type != 'python':
   #  _implementation_type = 'python'
 
 
+# This environment variable can be used to switch between the two
+# 'cpp' implementations. Right now only 1 and 2 are valid values. Any
+# other value will be ignored.
+_implementation_version_str = os.getenv(
+    'PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION',
+    '1')
+
+
+if _implementation_version_str not in ('1', '2'):
+  raise ValueError(
+      "unsupported PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION: '" +
+      _implementation_version_str + "' (supported versions: 1, 2)"
+      )
+
+
+_implementation_version = int(_implementation_version_str)
+
+
+
 # Usage of this function is discouraged. Clients shouldn't care which
 # implementation of the API is in use. Note that there is no guarantee
 # that differences between APIs will be maintained.
 # Please don't use this function if possible.
 def Type():
   return _implementation_type
+
+# See comment on 'Type' above.
+def Version():
+  return _implementation_version
diff --git a/python/google/protobuf/internal/containers.py b/python/google/protobuf/internal/containers.py
index 097a3c26..34b35f8a 100755
--- a/python/google/protobuf/internal/containers.py
+++ b/python/google/protobuf/internal/containers.py
@@ -78,8 +78,13 @@ class BaseContainer(object):
   def __repr__(self):
     return repr(self._values)
 
-  def sort(self, sort_function=cmp):
-    self._values.sort(sort_function)
+  def sort(self, *args, **kwargs):
+    # Continue to support the old sort_function keyword argument.
+    # This is expected to be a rare occurrence, so use LBYL to avoid
+    # the overhead of actually catching KeyError.
+    if 'sort_function' in kwargs:
+      kwargs['cmp'] = kwargs.pop('sort_function')
+    self._values.sort(*args, **kwargs)
 
 
 class RepeatedScalarFieldContainer(BaseContainer):
@@ -235,6 +240,11 @@ class RepeatedCompositeFieldContainer(BaseContainer):
     """
     self.extend(other._values)
 
+  def remove(self, elem):
+    """Removes an item from the list. Similar to list.remove()."""
+    self._values.remove(elem)
+    self._message_listener.Modified()
+
   def __getslice__(self, start, stop):
     """Retrieves the subset of items from between the specified indices."""
     return self._values[start:stop]
diff --git a/python/google/protobuf/internal/cpp_message.py b/python/google/protobuf/internal/cpp_message.py
index 3f426502..23ab9ba4 100755
--- a/python/google/protobuf/internal/cpp_message.py
+++ b/python/google/protobuf/internal/cpp_message.py
@@ -34,8 +34,10 @@ Descriptor objects at runtime backed by the protocol buffer C++ API.
 
 __author__ = 'petar@google.com (Petar Petrov)'
 
+import copy_reg
 import operator
 from google.protobuf.internal import _net_proto2___python
+from google.protobuf.internal import enum_type_wrapper
 from google.protobuf import message
 
 
@@ -156,10 +158,12 @@ class RepeatedScalarContainer(object):
   def __hash__(self):
     raise TypeError('unhashable object')
 
-  def sort(self, sort_function=cmp):
-    values = self[slice(None, None, None)]
-    values.sort(sort_function)
-    self._cmsg.AssignRepeatedScalar(self._cfield_descriptor, values)
+  def sort(self, *args, **kwargs):
+    # Maintain compatibility with the previous interface.
+    if 'sort_function' in kwargs:
+      kwargs['cmp'] = kwargs.pop('sort_function')
+    self._cmsg.AssignRepeatedScalar(self._cfield_descriptor,
+                                    sorted(self, *args, **kwargs))
 
 
 def RepeatedScalarProperty(cdescriptor):
@@ -202,6 +206,12 @@ class RepeatedCompositeContainer(object):
     for message in elem_seq:
       self.add().MergeFrom(message)
 
+  def remove(self, value):
+    # TODO(protocol-devel): This is inefficient as it needs to generate a
+    # message pointer for each message only to do index().  Move this to a C++
+    # extension function.
+    self.__delitem__(self[slice(None, None, None)].index(value))
+
   def MergeFrom(self, other):
     for message in other[:]:
       self.add().MergeFrom(message)
@@ -236,27 +246,29 @@ class RepeatedCompositeContainer(object):
   def __hash__(self):
     raise TypeError('unhashable object')
 
-  def sort(self, sort_function=cmp):
-    messages = []
-    for index in range(len(self)):
-      # messages[i][0] is where the i-th element of the new array has to come
-      # from.
-      # messages[i][1] is where the i-th element of the old array has to go.
-      messages.append([index, 0, self[index]])
-    messages.sort(lambda x,y: sort_function(x[2], y[2]))
+  def sort(self, cmp=None, key=None, reverse=False, **kwargs):
+    # Maintain compatibility with the old interface.
+    if cmp is None and 'sort_function' in kwargs:
+      cmp = kwargs.pop('sort_function')
 
-    # Remember which position each elements has to move to.
-    for i in range(len(messages)):
-      messages[messages[i][0]][1] = i
+    # The cmp function, if provided, is passed the results of the key function,
+    # so we only need to wrap one of them.
+    if key is None:
+      index_key = self.__getitem__
+    else:
+      index_key = lambda i: key(self[i])
+
+    # Sort the list of current indexes by the underlying object.
+    indexes = range(len(self))
+    indexes.sort(cmp=cmp, key=index_key, reverse=reverse)
 
     # Apply the transposition.
-    for i in range(len(messages)):
-      from_position = messages[i][0]
-      if i == from_position:
+    for dest, src in enumerate(indexes):
+      if dest == src:
         continue
-      self._cmsg.SwapRepeatedFieldElements(
-          self._cfield_descriptor, i, from_position)
-      messages[messages[i][1]][0] = from_position
+      self._cmsg.SwapRepeatedFieldElements(self._cfield_descriptor, dest, src)
+      # Don't swap the same value twice.
+      indexes[src] = src
 
 
 def RepeatedCompositeProperty(cdescriptor, message_type):
@@ -359,11 +371,12 @@ class ExtensionDict(object):
     return None
 
 
-def NewMessage(message_descriptor, dictionary):
+def NewMessage(bases, message_descriptor, dictionary):
   """Creates a new protocol message *class*."""
   _AddClassAttributesForNestedExtensions(message_descriptor, dictionary)
   _AddEnumValues(message_descriptor, dictionary)
   _AddDescriptors(message_descriptor, dictionary)
+  return bases
 
 
 def InitMessage(message_descriptor, cls):
@@ -372,6 +385,7 @@ def InitMessage(message_descriptor, cls):
   _AddInitMethod(message_descriptor, cls)
   _AddMessageMethods(message_descriptor, cls)
   _AddPropertiesForExtensions(message_descriptor, cls)
+  copy_reg.pickle(cls, lambda obj: (cls, (), obj.__getstate__()))
 
 
 def _AddDescriptors(message_descriptor, dictionary):
@@ -387,7 +401,7 @@ def _AddDescriptors(message_descriptor, dictionary):
         field.full_name)
 
   dictionary['__slots__'] = list(dictionary['__descriptors'].iterkeys()) + [
-      '_cmsg', '_owner', '_composite_fields', 'Extensions']
+      '_cmsg', '_owner', '_composite_fields', 'Extensions', '_HACK_REFCOUNTS']
 
 
 def _AddEnumValues(message_descriptor, dictionary):
@@ -398,6 +412,7 @@ def _AddEnumValues(message_descriptor, dictionary):
     dictionary: Class dictionary that should be populated.
   """
   for enum_type in message_descriptor.enum_types:
+    dictionary[enum_type.name] = enum_type_wrapper.EnumTypeWrapper(enum_type)
     for enum_value in enum_type.values:
       dictionary[enum_value.name] = enum_value.number
 
@@ -439,28 +454,35 @@ def _AddInitMethod(message_descriptor, cls):
   def Init(self, **kwargs):
     """Message constructor."""
     cmessage = kwargs.pop('__cmessage', None)
-    if cmessage is None:
-      self._cmsg = NewCMessage(message_descriptor.full_name)
-    else:
+    if cmessage:
       self._cmsg = cmessage
+    else:
+      self._cmsg = NewCMessage(message_descriptor.full_name)
 
     # Keep a reference to the owner, as the owner keeps a reference to the
     # underlying protocol buffer message.
     owner = kwargs.pop('__owner', None)
-    if owner is not None:
+    if owner:
       self._owner = owner
 
-    self.Extensions = ExtensionDict(self)
+    if message_descriptor.is_extendable:
+      self.Extensions = ExtensionDict(self)
+    else:
+      # Reference counting in the C++ code is broken and depends on
+      # the Extensions reference to keep this object alive during unit
+      # tests (see b/4856052).  Remove this once b/4945904 is fixed.
+      self._HACK_REFCOUNTS = self
     self._composite_fields = {}
 
     for field_name, field_value in kwargs.iteritems():
       field_cdescriptor = self.__descriptors.get(field_name, None)
-      if field_cdescriptor is None:
+      if not field_cdescriptor:
         raise ValueError('Protocol message has no "%s" field.' % field_name)
       if field_cdescriptor.label == _LABEL_REPEATED:
         if field_cdescriptor.cpp_type == _CPPTYPE_MESSAGE:
+          field_name = getattr(self, field_name)
           for val in field_value:
-            getattr(self, field_name).add().MergeFrom(val)
+            field_name.add().MergeFrom(val)
         else:
           getattr(self, field_name).extend(field_value)
       elif field_cdescriptor.cpp_type == _CPPTYPE_MESSAGE:
@@ -497,12 +519,34 @@ def _AddMessageMethods(message_descriptor, cls):
     return self._cmsg.HasField(field_name)
 
   def ClearField(self, field_name):
+    child_cmessage = None
     if field_name in self._composite_fields:
+      child_field = self._composite_fields[field_name]
       del self._composite_fields[field_name]
-    self._cmsg.ClearField(field_name)
+
+      child_cdescriptor = self.__descriptors[field_name]
+      # TODO(anuraag): Support clearing repeated message fields as well.
+      if (child_cdescriptor.label != _LABEL_REPEATED and
+          child_cdescriptor.cpp_type == _CPPTYPE_MESSAGE):
+        child_field._owner = None
+        child_cmessage = child_field._cmsg
+
+    if child_cmessage is not None:
+      self._cmsg.ClearField(field_name, child_cmessage)
+    else:
+      self._cmsg.ClearField(field_name)
 
   def Clear(self):
-    return self._cmsg.Clear()
+    cmessages_to_release = []
+    for field_name, child_field in self._composite_fields.iteritems():
+      child_cdescriptor = self.__descriptors[field_name]
+      # TODO(anuraag): Support clearing repeated message fields as well.
+      if (child_cdescriptor.label != _LABEL_REPEATED and
+          child_cdescriptor.cpp_type == _CPPTYPE_MESSAGE):
+        child_field._owner = None
+        cmessages_to_release.append((child_cdescriptor, child_field._cmsg))
+    self._composite_fields.clear()
+    self._cmsg.Clear(cmessages_to_release)
 
   def IsInitialized(self, errors=None):
     if self._cmsg.IsInitialized():
@@ -514,8 +558,8 @@ def _AddMessageMethods(message_descriptor, cls):
   def SerializeToString(self):
     if not self.IsInitialized():
       raise message.EncodeError(
-          'Message is missing required fields: ' +
-          ','.join(self.FindInitializationErrors()))
+          'Message %s is missing required fields: %s' % (
+          self._cmsg.full_name, ','.join(self.FindInitializationErrors())))
     return self._cmsg.SerializeToString()
 
   def SerializePartialToString(self):
@@ -534,7 +578,8 @@ def _AddMessageMethods(message_descriptor, cls):
   def MergeFrom(self, msg):
     if not isinstance(msg, cls):
       raise TypeError(
-          "Parameter to MergeFrom() must be instance of same class.")
+          "Parameter to MergeFrom() must be instance of same class: "
+          "expected %s got %s." % (cls.__name__, type(msg).__name__))
     self._cmsg.MergeFrom(msg._cmsg)
 
   def CopyFrom(self, msg):
@@ -581,6 +626,8 @@ def _AddMessageMethods(message_descriptor, cls):
     raise TypeError('unhashable object')
 
   def __unicode__(self):
+    # Lazy import to prevent circular import when text_format imports this file.
+    from google.protobuf import text_format
     return text_format.MessageToString(self, as_utf8=True).decode('utf-8')
 
   # Attach the local methods to the message class.
diff --git a/python/google/protobuf/internal/decoder.py b/python/google/protobuf/internal/decoder.py
index 55f746f5..cb6f5729 100755
--- a/python/google/protobuf/internal/decoder.py
+++ b/python/google/protobuf/internal/decoder.py
@@ -576,6 +576,7 @@ def MessageSetItemDecoder(extensions_by_number):
   local_SkipField = SkipField
 
   def DecodeItem(buffer, pos, end, message, field_dict):
+    message_set_item_start = pos
     type_id = -1
     message_start = -1
     message_end = -1
@@ -614,6 +615,11 @@ def MessageSetItemDecoder(extensions_by_number):
         # The only reason _InternalParse would return early is if it encountered
         # an end-group tag.
         raise _DecodeError('Unexpected end-group tag.')
+    else:
+      if not message._unknown_fields:
+        message._unknown_fields = []
+      message._unknown_fields.append((MESSAGE_SET_ITEM_TAG,
+                                      buffer[message_set_item_start:pos]))
 
     return pos
 
diff --git a/python/google/protobuf/internal/descriptor_database_test.py b/python/google/protobuf/internal/descriptor_database_test.py
new file mode 100644
index 00000000..d0ca7892
--- /dev/null
+++ b/python/google/protobuf/internal/descriptor_database_test.py
@@ -0,0 +1,63 @@
+#! /usr/bin/python
+#
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Tests for google.protobuf.descriptor_database."""
+
+__author__ = 'matthewtoia@google.com (Matt Toia)'
+
+import unittest
+from google.protobuf import descriptor_pb2
+from google.protobuf.internal import factory_test2_pb2
+from google.protobuf import descriptor_database
+
+
+class DescriptorDatabaseTest(unittest.TestCase):
+
+  def testAdd(self):
+    db = descriptor_database.DescriptorDatabase()
+    file_desc_proto = descriptor_pb2.FileDescriptorProto.FromString(
+        factory_test2_pb2.DESCRIPTOR.serialized_pb)
+    db.Add(file_desc_proto)
+
+    self.assertEquals(file_desc_proto, db.FindFileByName(
+        'net/proto2/python/internal/factory_test2.proto'))
+    self.assertEquals(file_desc_proto, db.FindFileContainingSymbol(
+        'net.proto2.python.internal.Factory2Message'))
+    self.assertEquals(file_desc_proto, db.FindFileContainingSymbol(
+        'net.proto2.python.internal.Factory2Message.NestedFactory2Message'))
+    self.assertEquals(file_desc_proto, db.FindFileContainingSymbol(
+        'net.proto2.python.internal.Factory2Enum'))
+    self.assertEquals(file_desc_proto, db.FindFileContainingSymbol(
+        'net.proto2.python.internal.Factory2Message.NestedFactory2Enum'))
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/python/google/protobuf/internal/descriptor_pool_test.py b/python/google/protobuf/internal/descriptor_pool_test.py
new file mode 100644
index 00000000..a615d787
--- /dev/null
+++ b/python/google/protobuf/internal/descriptor_pool_test.py
@@ -0,0 +1,220 @@
+#! /usr/bin/python
+#
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Tests for google.protobuf.descriptor_pool."""
+
+__author__ = 'matthewtoia@google.com (Matt Toia)'
+
+import unittest
+from google.protobuf import descriptor_pb2
+from google.protobuf.internal import factory_test1_pb2
+from google.protobuf.internal import factory_test2_pb2
+from google.protobuf import descriptor
+from google.protobuf import descriptor_database
+from google.protobuf import descriptor_pool
+
+
+class DescriptorPoolTest(unittest.TestCase):
+
+  def setUp(self):
+    self.pool = descriptor_pool.DescriptorPool()
+    self.factory_test1_fd = descriptor_pb2.FileDescriptorProto.FromString(
+        factory_test1_pb2.DESCRIPTOR.serialized_pb)
+    self.factory_test2_fd = descriptor_pb2.FileDescriptorProto.FromString(
+        factory_test2_pb2.DESCRIPTOR.serialized_pb)
+    self.pool.Add(self.factory_test1_fd)
+    self.pool.Add(self.factory_test2_fd)
+
+  def testFindFileByName(self):
+    name1 = 'net/proto2/python/internal/factory_test1.proto'
+    file_desc1 = self.pool.FindFileByName(name1)
+    self.assertIsInstance(file_desc1, descriptor.FileDescriptor)
+    self.assertEquals(name1, file_desc1.name)
+    self.assertEquals('net.proto2.python.internal', file_desc1.package)
+    self.assertIn('Factory1Message', file_desc1.message_types_by_name)
+
+    name2 = 'net/proto2/python/internal/factory_test2.proto'
+    file_desc2 = self.pool.FindFileByName(name2)
+    self.assertIsInstance(file_desc2, descriptor.FileDescriptor)
+    self.assertEquals(name2, file_desc2.name)
+    self.assertEquals('net.proto2.python.internal', file_desc2.package)
+    self.assertIn('Factory2Message', file_desc2.message_types_by_name)
+
+  def testFindFileByNameFailure(self):
+    try:
+      self.pool.FindFileByName('Does not exist')
+      self.fail('Expected KeyError')
+    except KeyError:
+      pass
+
+  def testFindFileContainingSymbol(self):
+    file_desc1 = self.pool.FindFileContainingSymbol(
+        'net.proto2.python.internal.Factory1Message')
+    self.assertIsInstance(file_desc1, descriptor.FileDescriptor)
+    self.assertEquals('net/proto2/python/internal/factory_test1.proto',
+                      file_desc1.name)
+    self.assertEquals('net.proto2.python.internal', file_desc1.package)
+    self.assertIn('Factory1Message', file_desc1.message_types_by_name)
+
+    file_desc2 = self.pool.FindFileContainingSymbol(
+        'net.proto2.python.internal.Factory2Message')
+    self.assertIsInstance(file_desc2, descriptor.FileDescriptor)
+    self.assertEquals('net/proto2/python/internal/factory_test2.proto',
+                      file_desc2.name)
+    self.assertEquals('net.proto2.python.internal', file_desc2.package)
+    self.assertIn('Factory2Message', file_desc2.message_types_by_name)
+
+  def testFindFileContainingSymbolFailure(self):
+    try:
+      self.pool.FindFileContainingSymbol('Does not exist')
+      self.fail('Expected KeyError')
+    except KeyError:
+      pass
+
+  def testFindMessageTypeByName(self):
+    msg1 = self.pool.FindMessageTypeByName(
+        'net.proto2.python.internal.Factory1Message')
+    self.assertIsInstance(msg1, descriptor.Descriptor)
+    self.assertEquals('Factory1Message', msg1.name)
+    self.assertEquals('net.proto2.python.internal.Factory1Message',
+                      msg1.full_name)
+    self.assertEquals(None, msg1.containing_type)
+
+    nested_msg1 = msg1.nested_types[0]
+    self.assertEquals('NestedFactory1Message', nested_msg1.name)
+    self.assertEquals(msg1, nested_msg1.containing_type)
+
+    nested_enum1 = msg1.enum_types[0]
+    self.assertEquals('NestedFactory1Enum', nested_enum1.name)
+    self.assertEquals(msg1, nested_enum1.containing_type)
+
+    self.assertEquals(nested_msg1, msg1.fields_by_name[
+        'nested_factory_1_message'].message_type)
+    self.assertEquals(nested_enum1, msg1.fields_by_name[
+        'nested_factory_1_enum'].enum_type)
+
+    msg2 = self.pool.FindMessageTypeByName(
+        'net.proto2.python.internal.Factory2Message')
+    self.assertIsInstance(msg2, descriptor.Descriptor)
+    self.assertEquals('Factory2Message', msg2.name)
+    self.assertEquals('net.proto2.python.internal.Factory2Message',
+                      msg2.full_name)
+    self.assertIsNone(msg2.containing_type)
+
+    nested_msg2 = msg2.nested_types[0]
+    self.assertEquals('NestedFactory2Message', nested_msg2.name)
+    self.assertEquals(msg2, nested_msg2.containing_type)
+
+    nested_enum2 = msg2.enum_types[0]
+    self.assertEquals('NestedFactory2Enum', nested_enum2.name)
+    self.assertEquals(msg2, nested_enum2.containing_type)
+
+    self.assertEquals(nested_msg2, msg2.fields_by_name[
+        'nested_factory_2_message'].message_type)
+    self.assertEquals(nested_enum2, msg2.fields_by_name[
+        'nested_factory_2_enum'].enum_type)
+
+    self.assertTrue(msg2.fields_by_name['int_with_default'].has_default)
+    self.assertEquals(
+        1776, msg2.fields_by_name['int_with_default'].default_value)
+
+    self.assertTrue(msg2.fields_by_name['double_with_default'].has_default)
+    self.assertEquals(
+        9.99, msg2.fields_by_name['double_with_default'].default_value)
+
+    self.assertTrue(msg2.fields_by_name['string_with_default'].has_default)
+    self.assertEquals(
+        'hello world', msg2.fields_by_name['string_with_default'].default_value)
+
+    self.assertTrue(msg2.fields_by_name['bool_with_default'].has_default)
+    self.assertFalse(msg2.fields_by_name['bool_with_default'].default_value)
+
+    self.assertTrue(msg2.fields_by_name['enum_with_default'].has_default)
+    self.assertEquals(
+        1, msg2.fields_by_name['enum_with_default'].default_value)
+
+    msg3 = self.pool.FindMessageTypeByName(
+        'net.proto2.python.internal.Factory2Message.NestedFactory2Message')
+    self.assertEquals(nested_msg2, msg3)
+
+  def testFindMessageTypeByNameFailure(self):
+    try:
+      self.pool.FindMessageTypeByName('Does not exist')
+      self.fail('Expected KeyError')
+    except KeyError:
+      pass
+
+  def testFindEnumTypeByName(self):
+    enum1 = self.pool.FindEnumTypeByName(
+        'net.proto2.python.internal.Factory1Enum')
+    self.assertIsInstance(enum1, descriptor.EnumDescriptor)
+    self.assertEquals(0, enum1.values_by_name['FACTORY_1_VALUE_0'].number)
+    self.assertEquals(1, enum1.values_by_name['FACTORY_1_VALUE_1'].number)
+
+    nested_enum1 = self.pool.FindEnumTypeByName(
+        'net.proto2.python.internal.Factory1Message.NestedFactory1Enum')
+    self.assertIsInstance(nested_enum1, descriptor.EnumDescriptor)
+    self.assertEquals(
+        0, nested_enum1.values_by_name['NESTED_FACTORY_1_VALUE_0'].number)
+    self.assertEquals(
+        1, nested_enum1.values_by_name['NESTED_FACTORY_1_VALUE_1'].number)
+
+    enum2 = self.pool.FindEnumTypeByName(
+        'net.proto2.python.internal.Factory2Enum')
+    self.assertIsInstance(enum2, descriptor.EnumDescriptor)
+    self.assertEquals(0, enum2.values_by_name['FACTORY_2_VALUE_0'].number)
+    self.assertEquals(1, enum2.values_by_name['FACTORY_2_VALUE_1'].number)
+
+    nested_enum2 = self.pool.FindEnumTypeByName(
+        'net.proto2.python.internal.Factory2Message.NestedFactory2Enum')
+    self.assertIsInstance(nested_enum2, descriptor.EnumDescriptor)
+    self.assertEquals(
+        0, nested_enum2.values_by_name['NESTED_FACTORY_2_VALUE_0'].number)
+    self.assertEquals(
+        1, nested_enum2.values_by_name['NESTED_FACTORY_2_VALUE_1'].number)
+
+  def testFindEnumTypeByNameFailure(self):
+    try:
+      self.pool.FindEnumTypeByName('Does not exist')
+      self.fail('Expected KeyError')
+    except KeyError:
+      pass
+
+  def testUserDefinedDB(self):
+    db = descriptor_database.DescriptorDatabase()
+    self.pool = descriptor_pool.DescriptorPool(db)
+    db.Add(self.factory_test1_fd)
+    db.Add(self.factory_test2_fd)
+    self.testFindMessageTypeByName()
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/python/google/protobuf/internal/descriptor_test.py b/python/google/protobuf/internal/descriptor_test.py
index 05c27452..c74f882e 100755
--- a/python/google/protobuf/internal/descriptor_test.py
+++ b/python/google/protobuf/internal/descriptor_test.py
@@ -35,6 +35,7 @@
 __author__ = 'robinson@google.com (Will Robinson)'
 
 import unittest
+from google.protobuf import unittest_custom_options_pb2
 from google.protobuf import unittest_import_pb2
 from google.protobuf import unittest_pb2
 from google.protobuf import descriptor_pb2
@@ -101,6 +102,15 @@ class DescriptorTest(unittest.TestCase):
             self.my_method
         ])
 
+  def testEnumValueName(self):
+    self.assertEqual(self.my_message.EnumValueName('ForeignEnum', 4),
+                     'FOREIGN_FOO')
+
+    self.assertEqual(
+        self.my_message.enum_types_by_name[
+            'ForeignEnum'].values_by_number[4].name,
+        self.my_message.EnumValueName('ForeignEnum', 4))
+
   def testEnumFixups(self):
     self.assertEqual(self.my_enum, self.my_enum.values[0].type)
 
@@ -125,6 +135,257 @@ class DescriptorTest(unittest.TestCase):
     self.assertEqual(self.my_service.GetOptions(),
                      descriptor_pb2.ServiceOptions())
 
+  def testSimpleCustomOptions(self):
+    file_descriptor = unittest_custom_options_pb2.DESCRIPTOR
+    message_descriptor =\
+        unittest_custom_options_pb2.TestMessageWithCustomOptions.DESCRIPTOR
+    field_descriptor = message_descriptor.fields_by_name["field1"]
+    enum_descriptor = message_descriptor.enum_types_by_name["AnEnum"]
+    enum_value_descriptor =\
+        message_descriptor.enum_values_by_name["ANENUM_VAL2"]
+    service_descriptor =\
+        unittest_custom_options_pb2.TestServiceWithCustomOptions.DESCRIPTOR
+    method_descriptor = service_descriptor.FindMethodByName("Foo")
+
+    file_options = file_descriptor.GetOptions()
+    file_opt1 = unittest_custom_options_pb2.file_opt1
+    self.assertEqual(9876543210, file_options.Extensions[file_opt1])
+    message_options = message_descriptor.GetOptions()
+    message_opt1 = unittest_custom_options_pb2.message_opt1
+    self.assertEqual(-56, message_options.Extensions[message_opt1])
+    field_options = field_descriptor.GetOptions()
+    field_opt1 = unittest_custom_options_pb2.field_opt1
+    self.assertEqual(8765432109, field_options.Extensions[field_opt1])
+    field_opt2 = unittest_custom_options_pb2.field_opt2
+    self.assertEqual(42, field_options.Extensions[field_opt2])
+    enum_options = enum_descriptor.GetOptions()
+    enum_opt1 = unittest_custom_options_pb2.enum_opt1
+    self.assertEqual(-789, enum_options.Extensions[enum_opt1])
+    enum_value_options = enum_value_descriptor.GetOptions()
+    enum_value_opt1 = unittest_custom_options_pb2.enum_value_opt1
+    self.assertEqual(123, enum_value_options.Extensions[enum_value_opt1])
+
+    service_options = service_descriptor.GetOptions()
+    service_opt1 = unittest_custom_options_pb2.service_opt1
+    self.assertEqual(-9876543210, service_options.Extensions[service_opt1])
+    method_options = method_descriptor.GetOptions()
+    method_opt1 = unittest_custom_options_pb2.method_opt1
+    self.assertEqual(unittest_custom_options_pb2.METHODOPT1_VAL2,
+                     method_options.Extensions[method_opt1])
+
+  def testDifferentCustomOptionTypes(self):
+    kint32min = -2**31
+    kint64min = -2**63
+    kint32max = 2**31 - 1
+    kint64max = 2**63 - 1
+    kuint32max = 2**32 - 1
+    kuint64max = 2**64 - 1
+
+    message_descriptor =\
+        unittest_custom_options_pb2.CustomOptionMinIntegerValues.DESCRIPTOR
+    message_options = message_descriptor.GetOptions()
+    self.assertEqual(False, message_options.Extensions[
+        unittest_custom_options_pb2.bool_opt])
+    self.assertEqual(kint32min, message_options.Extensions[
+        unittest_custom_options_pb2.int32_opt])
+    self.assertEqual(kint64min, message_options.Extensions[
+        unittest_custom_options_pb2.int64_opt])
+    self.assertEqual(0, message_options.Extensions[
+        unittest_custom_options_pb2.uint32_opt])
+    self.assertEqual(0, message_options.Extensions[
+        unittest_custom_options_pb2.uint64_opt])
+    self.assertEqual(kint32min, message_options.Extensions[
+        unittest_custom_options_pb2.sint32_opt])
+    self.assertEqual(kint64min, message_options.Extensions[
+        unittest_custom_options_pb2.sint64_opt])
+    self.assertEqual(0, message_options.Extensions[
+        unittest_custom_options_pb2.fixed32_opt])
+    self.assertEqual(0, message_options.Extensions[
+        unittest_custom_options_pb2.fixed64_opt])
+    self.assertEqual(kint32min, message_options.Extensions[
+        unittest_custom_options_pb2.sfixed32_opt])
+    self.assertEqual(kint64min, message_options.Extensions[
+        unittest_custom_options_pb2.sfixed64_opt])
+
+    message_descriptor =\
+        unittest_custom_options_pb2.CustomOptionMaxIntegerValues.DESCRIPTOR
+    message_options = message_descriptor.GetOptions()
+    self.assertEqual(True, message_options.Extensions[
+        unittest_custom_options_pb2.bool_opt])
+    self.assertEqual(kint32max, message_options.Extensions[
+        unittest_custom_options_pb2.int32_opt])
+    self.assertEqual(kint64max, message_options.Extensions[
+        unittest_custom_options_pb2.int64_opt])
+    self.assertEqual(kuint32max, message_options.Extensions[
+        unittest_custom_options_pb2.uint32_opt])
+    self.assertEqual(kuint64max, message_options.Extensions[
+        unittest_custom_options_pb2.uint64_opt])
+    self.assertEqual(kint32max, message_options.Extensions[
+        unittest_custom_options_pb2.sint32_opt])
+    self.assertEqual(kint64max, message_options.Extensions[
+        unittest_custom_options_pb2.sint64_opt])
+    self.assertEqual(kuint32max, message_options.Extensions[
+        unittest_custom_options_pb2.fixed32_opt])
+    self.assertEqual(kuint64max, message_options.Extensions[
+        unittest_custom_options_pb2.fixed64_opt])
+    self.assertEqual(kint32max, message_options.Extensions[
+        unittest_custom_options_pb2.sfixed32_opt])
+    self.assertEqual(kint64max, message_options.Extensions[
+        unittest_custom_options_pb2.sfixed64_opt])
+
+    message_descriptor =\
+        unittest_custom_options_pb2.CustomOptionOtherValues.DESCRIPTOR
+    message_options = message_descriptor.GetOptions()
+    self.assertEqual(-100, message_options.Extensions[
+        unittest_custom_options_pb2.int32_opt])
+    self.assertAlmostEqual(12.3456789, message_options.Extensions[
+        unittest_custom_options_pb2.float_opt], 6)
+    self.assertAlmostEqual(1.234567890123456789, message_options.Extensions[
+        unittest_custom_options_pb2.double_opt])
+    self.assertEqual("Hello, \"World\"", message_options.Extensions[
+        unittest_custom_options_pb2.string_opt])
+    self.assertEqual("Hello\0World", message_options.Extensions[
+        unittest_custom_options_pb2.bytes_opt])
+    dummy_enum = unittest_custom_options_pb2.DummyMessageContainingEnum
+    self.assertEqual(
+        dummy_enum.TEST_OPTION_ENUM_TYPE2,
+        message_options.Extensions[unittest_custom_options_pb2.enum_opt])
+
+    message_descriptor =\
+        unittest_custom_options_pb2.SettingRealsFromPositiveInts.DESCRIPTOR
+    message_options = message_descriptor.GetOptions()
+    self.assertAlmostEqual(12, message_options.Extensions[
+        unittest_custom_options_pb2.float_opt], 6)
+    self.assertAlmostEqual(154, message_options.Extensions[
+        unittest_custom_options_pb2.double_opt])
+
+    message_descriptor =\
+        unittest_custom_options_pb2.SettingRealsFromNegativeInts.DESCRIPTOR
+    message_options = message_descriptor.GetOptions()
+    self.assertAlmostEqual(-12, message_options.Extensions[
+        unittest_custom_options_pb2.float_opt], 6)
+    self.assertAlmostEqual(-154, message_options.Extensions[
+        unittest_custom_options_pb2.double_opt])
+
+  def testComplexExtensionOptions(self):
+    descriptor =\
+        unittest_custom_options_pb2.VariousComplexOptions.DESCRIPTOR
+    options = descriptor.GetOptions()
+    self.assertEqual(42, options.Extensions[
+        unittest_custom_options_pb2.complex_opt1].foo)
+    self.assertEqual(324, options.Extensions[
+        unittest_custom_options_pb2.complex_opt1].Extensions[
+            unittest_custom_options_pb2.quux])
+    self.assertEqual(876, options.Extensions[
+        unittest_custom_options_pb2.complex_opt1].Extensions[
+            unittest_custom_options_pb2.corge].qux)
+    self.assertEqual(987, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].baz)
+    self.assertEqual(654, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].Extensions[
+            unittest_custom_options_pb2.grault])
+    self.assertEqual(743, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].bar.foo)
+    self.assertEqual(1999, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].bar.Extensions[
+            unittest_custom_options_pb2.quux])
+    self.assertEqual(2008, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].bar.Extensions[
+            unittest_custom_options_pb2.corge].qux)
+    self.assertEqual(741, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].Extensions[
+            unittest_custom_options_pb2.garply].foo)
+    self.assertEqual(1998, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].Extensions[
+            unittest_custom_options_pb2.garply].Extensions[
+                unittest_custom_options_pb2.quux])
+    self.assertEqual(2121, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].Extensions[
+            unittest_custom_options_pb2.garply].Extensions[
+                unittest_custom_options_pb2.corge].qux)
+    self.assertEqual(1971, options.Extensions[
+        unittest_custom_options_pb2.ComplexOptionType2
+        .ComplexOptionType4.complex_opt4].waldo)
+    self.assertEqual(321, options.Extensions[
+        unittest_custom_options_pb2.complex_opt2].fred.waldo)
+    self.assertEqual(9, options.Extensions[
+        unittest_custom_options_pb2.complex_opt3].qux)
+    self.assertEqual(22, options.Extensions[
+        unittest_custom_options_pb2.complex_opt3].complexoptiontype5.plugh)
+    self.assertEqual(24, options.Extensions[
+        unittest_custom_options_pb2.complexopt6].xyzzy)
+
+  # Check that aggregate options were parsed and saved correctly in
+  # the appropriate descriptors.
+  def testAggregateOptions(self):
+    file_descriptor = unittest_custom_options_pb2.DESCRIPTOR
+    message_descriptor =\
+        unittest_custom_options_pb2.AggregateMessage.DESCRIPTOR
+    field_descriptor = message_descriptor.fields_by_name["fieldname"]
+    enum_descriptor = unittest_custom_options_pb2.AggregateEnum.DESCRIPTOR
+    enum_value_descriptor = enum_descriptor.values_by_name["VALUE"]
+    service_descriptor =\
+        unittest_custom_options_pb2.AggregateService.DESCRIPTOR
+    method_descriptor = service_descriptor.FindMethodByName("Method")
+
+    # Tests for the different types of data embedded in fileopt
+    file_options = file_descriptor.GetOptions().Extensions[
+        unittest_custom_options_pb2.fileopt]
+    self.assertEqual(100, file_options.i)
+    self.assertEqual("FileAnnotation", file_options.s)
+    self.assertEqual("NestedFileAnnotation", file_options.sub.s)
+    self.assertEqual("FileExtensionAnnotation", file_options.file.Extensions[
+        unittest_custom_options_pb2.fileopt].s)
+    self.assertEqual("EmbeddedMessageSetElement", file_options.mset.Extensions[
+        unittest_custom_options_pb2.AggregateMessageSetElement
+        .message_set_extension].s)
+
+    # Simple tests for all the other types of annotations
+    self.assertEqual(
+        "MessageAnnotation",
+        message_descriptor.GetOptions().Extensions[
+            unittest_custom_options_pb2.msgopt].s)
+    self.assertEqual(
+        "FieldAnnotation",
+        field_descriptor.GetOptions().Extensions[
+            unittest_custom_options_pb2.fieldopt].s)
+    self.assertEqual(
+        "EnumAnnotation",
+        enum_descriptor.GetOptions().Extensions[
+            unittest_custom_options_pb2.enumopt].s)
+    self.assertEqual(
+        "EnumValueAnnotation",
+        enum_value_descriptor.GetOptions().Extensions[
+            unittest_custom_options_pb2.enumvalopt].s)
+    self.assertEqual(
+        "ServiceAnnotation",
+        service_descriptor.GetOptions().Extensions[
+            unittest_custom_options_pb2.serviceopt].s)
+    self.assertEqual(
+        "MethodAnnotation",
+        method_descriptor.GetOptions().Extensions[
+            unittest_custom_options_pb2.methodopt].s)
+
+  def testNestedOptions(self):
+    nested_message =\
+        unittest_custom_options_pb2.NestedOptionType.NestedMessage.DESCRIPTOR
+    self.assertEqual(1001, nested_message.GetOptions().Extensions[
+        unittest_custom_options_pb2.message_opt1])
+    nested_field = nested_message.fields_by_name["nested_field"]
+    self.assertEqual(1002, nested_field.GetOptions().Extensions[
+        unittest_custom_options_pb2.field_opt1])
+    outer_message =\
+        unittest_custom_options_pb2.NestedOptionType.DESCRIPTOR
+    nested_enum = outer_message.enum_types_by_name["NestedEnum"]
+    self.assertEqual(1003, nested_enum.GetOptions().Extensions[
+        unittest_custom_options_pb2.enum_opt1])
+    nested_enum_value = outer_message.enum_values_by_name["NESTED_ENUM_VALUE"]
+    self.assertEqual(1004, nested_enum_value.GetOptions().Extensions[
+        unittest_custom_options_pb2.enum_value_opt1])
+    nested_extension = outer_message.extensions_by_name["nested_extension"]
+    self.assertEqual(1005, nested_extension.GetOptions().Extensions[
+        unittest_custom_options_pb2.field_opt2])
+
   def testFileDescriptorReferences(self):
     self.assertEqual(self.my_enum.file, self.my_file)
     self.assertEqual(self.my_message.file, self.my_file)
@@ -273,6 +534,7 @@ class DescriptorCopyToProtoTest(unittest.TestCase):
     UNITTEST_IMPORT_FILE_DESCRIPTOR_ASCII = ("""
       name: 'google/protobuf/unittest_import.proto'
       package: 'protobuf_unittest_import'
+      dependency: 'google/protobuf/unittest_import_public.proto'
       message_type: <
         name: 'ImportMessage'
         field: <
@@ -302,6 +564,7 @@ class DescriptorCopyToProtoTest(unittest.TestCase):
         java_package: 'com.google.protobuf.test'
         optimize_for: 1  # SPEED
       >
+      public_dependency: 0
       """)
 
     self._InternalTestCopyToProto(
@@ -330,5 +593,21 @@ class DescriptorCopyToProtoTest(unittest.TestCase):
         TEST_SERVICE_ASCII)
 
 
+class MakeDescriptorTest(unittest.TestCase):
+  def testMakeDescriptorWithUnsignedIntField(self):
+    file_descriptor_proto = descriptor_pb2.FileDescriptorProto()
+    file_descriptor_proto.name = 'Foo'
+    message_type = file_descriptor_proto.message_type.add()
+    message_type.name = file_descriptor_proto.name
+    field = message_type.field.add()
+    field.number = 1
+    field.name = 'uint64_field'
+    field.label = descriptor.FieldDescriptor.LABEL_REQUIRED
+    field.type = descriptor.FieldDescriptor.TYPE_UINT64
+    result = descriptor.MakeDescriptor(message_type)
+    self.assertEqual(result.fields[0].cpp_type,
+                     descriptor.FieldDescriptor.CPPTYPE_UINT64)
+
+
 if __name__ == '__main__':
   unittest.main()
diff --git a/python/google/protobuf/internal/enum_type_wrapper.py b/python/google/protobuf/internal/enum_type_wrapper.py
new file mode 100644
index 00000000..7b28645a
--- /dev/null
+++ b/python/google/protobuf/internal/enum_type_wrapper.py
@@ -0,0 +1,89 @@
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""A simple wrapper around enum types to expose utility functions.
+
+Instances are created as properties with the same name as the enum they wrap
+on proto classes.  For usage, see:
+  reflection_test.py
+"""
+
+__author__ = 'rabsatt@google.com (Kevin Rabsatt)'
+
+
+class EnumTypeWrapper(object):
+  """A utility for finding the names of enum values."""
+
+  DESCRIPTOR = None
+
+  def __init__(self, enum_type):
+    """Inits EnumTypeWrapper with an EnumDescriptor."""
+    self._enum_type = enum_type
+    self.DESCRIPTOR = enum_type;
+
+  def Name(self, number):
+    """Returns a string containing the name of an enum value."""
+    if number in self._enum_type.values_by_number:
+      return self._enum_type.values_by_number[number].name
+    raise ValueError('Enum %s has no name defined for value %d' % (
+        self._enum_type.name, number))
+
+  def Value(self, name):
+    """Returns the value coresponding to the given enum name."""
+    if name in self._enum_type.values_by_name:
+      return self._enum_type.values_by_name[name].number
+    raise ValueError('Enum %s has no value defined for name %s' % (
+        self._enum_type.name, name))
+
+  def keys(self):
+    """Return a list of the string names in the enum.
+
+    These are returned in the order they were defined in the .proto file.
+    """
+
+    return [value_descriptor.name
+            for value_descriptor in self._enum_type.values]
+
+  def values(self):
+    """Return a list of the integer values in the enum.
+
+    These are returned in the order they were defined in the .proto file.
+    """
+
+    return [value_descriptor.number
+            for value_descriptor in self._enum_type.values]
+
+  def items(self):
+    """Return a list of the (name, value) pairs of the enum.
+
+    These are returned in the order they were defined in the .proto file.
+    """
+    return [(value_descriptor.name, value_descriptor.number)
+            for value_descriptor in self._enum_type.values]
diff --git a/python/google/protobuf/internal/factory_test1.proto b/python/google/protobuf/internal/factory_test1.proto
new file mode 100644
index 00000000..9f55e037
--- /dev/null
+++ b/python/google/protobuf/internal/factory_test1.proto
@@ -0,0 +1,55 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: matthewtoia@google.com (Matt Toia)
+
+
+package google.protobuf.python.internal;
+
+
+enum Factory1Enum {
+  FACTORY_1_VALUE_0 = 0;
+  FACTORY_1_VALUE_1 = 1;
+}
+
+message Factory1Message {
+  optional Factory1Enum factory_1_enum = 1;
+  enum NestedFactory1Enum {
+    NESTED_FACTORY_1_VALUE_0 = 0;
+    NESTED_FACTORY_1_VALUE_1 = 1;
+  }
+  optional NestedFactory1Enum nested_factory_1_enum = 2;
+  message NestedFactory1Message {
+    optional string value = 1;
+  }
+  optional NestedFactory1Message nested_factory_1_message = 3;
+  optional int32 scalar_value = 4;
+  repeated string list_value = 5;
+}
diff --git a/python/google/protobuf/internal/factory_test2.proto b/python/google/protobuf/internal/factory_test2.proto
new file mode 100644
index 00000000..d3ce4d7f
--- /dev/null
+++ b/python/google/protobuf/internal/factory_test2.proto
@@ -0,0 +1,77 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: matthewtoia@google.com (Matt Toia)
+
+
+package google.protobuf.python.internal;
+
+import "google/protobuf/internal/factory_test1.proto";
+
+
+enum Factory2Enum {
+  FACTORY_2_VALUE_0 = 0;
+  FACTORY_2_VALUE_1 = 1;
+}
+
+message Factory2Message {
+  required int32 mandatory = 1;
+  optional Factory2Enum factory_2_enum = 2;
+  enum NestedFactory2Enum {
+    NESTED_FACTORY_2_VALUE_0 = 0;
+    NESTED_FACTORY_2_VALUE_1 = 1;
+  }
+  optional NestedFactory2Enum nested_factory_2_enum = 3;
+  message NestedFactory2Message {
+    optional string value = 1;
+  }
+  optional NestedFactory2Message nested_factory_2_message = 4;
+  optional Factory1Message factory_1_message = 5;
+  optional Factory1Enum factory_1_enum = 6;
+  optional Factory1Message.NestedFactory1Enum nested_factory_1_enum = 7;
+  optional Factory1Message.NestedFactory1Message nested_factory_1_message = 8;
+  optional Factory2Message circular_message = 9;
+  optional string scalar_value = 10;
+  repeated string list_value = 11;
+  repeated group Grouped = 12 {
+    optional string part_1 = 13;
+    optional string part_2 = 14;
+  }
+  optional LoopMessage loop = 15;
+  optional int32 int_with_default = 16 [default = 1776];
+  optional double double_with_default = 17 [default = 9.99];
+  optional string string_with_default = 18 [default = "hello world"];
+  optional bool bool_with_default = 19 [default = false];
+  optional Factory2Enum enum_with_default = 20 [default = FACTORY_2_VALUE_1];
+}
+
+message LoopMessage {
+  optional Factory2Message loop = 1;
+}
diff --git a/python/google/protobuf/internal/generator_test.py b/python/google/protobuf/internal/generator_test.py
index b3f7d9b1..8343aba1 100755
--- a/python/google/protobuf/internal/generator_test.py
+++ b/python/google/protobuf/internal/generator_test.py
@@ -42,8 +42,10 @@ further ensures that we can use Python protocol message objects as we expect.
 __author__ = 'robinson@google.com (Will Robinson)'
 
 import unittest
+from google.protobuf.internal import test_bad_identifiers_pb2
 from google.protobuf import unittest_custom_options_pb2
 from google.protobuf import unittest_import_pb2
+from google.protobuf import unittest_import_public_pb2
 from google.protobuf import unittest_mset_pb2
 from google.protobuf import unittest_pb2
 from google.protobuf import unittest_no_generic_services_pb2
@@ -239,6 +241,29 @@ class GeneratorTest(unittest.TestCase):
         unittest_pb2._TESTALLTYPES_NESTEDMESSAGE.name in
         file_type.message_types_by_name)
 
+  def testPublicImports(self):
+    # Test public imports as embedded message.
+    all_type_proto = unittest_pb2.TestAllTypes()
+    self.assertEqual(0, all_type_proto.optional_public_import_message.e)
+
+    # PublicImportMessage is actually defined in unittest_import_public_pb2
+    # module, and is public imported by unittest_import_pb2 module.
+    public_import_proto = unittest_import_pb2.PublicImportMessage()
+    self.assertEqual(0, public_import_proto.e)
+    self.assertTrue(unittest_import_public_pb2.PublicImportMessage is
+                    unittest_import_pb2.PublicImportMessage)
+
+  def testBadIdentifiers(self):
+    # We're just testing that the code was imported without problems.
+    message = test_bad_identifiers_pb2.TestBadIdentifiers()
+    self.assertEqual(message.Extensions[test_bad_identifiers_pb2.message],
+                     "foo")
+    self.assertEqual(message.Extensions[test_bad_identifiers_pb2.descriptor],
+                     "bar")
+    self.assertEqual(message.Extensions[test_bad_identifiers_pb2.reflection],
+                     "baz")
+    self.assertEqual(message.Extensions[test_bad_identifiers_pb2.service],
+                     "qux")
 
 if __name__ == '__main__':
   unittest.main()
diff --git a/python/google/protobuf/internal/message_cpp_test.py b/python/google/protobuf/internal/message_cpp_test.py
new file mode 100644
index 00000000..0d84b320
--- /dev/null
+++ b/python/google/protobuf/internal/message_cpp_test.py
@@ -0,0 +1,45 @@
+#! /usr/bin/python
+#
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Tests for google.protobuf.internal.message_cpp."""
+
+__author__ = 'shahms@google.com (Shahms King)'
+
+import os
+os.environ['PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION'] = 'cpp'
+
+import unittest
+from google.protobuf.internal.message_test import *
+
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/python/google/protobuf/internal/message_factory_test.py b/python/google/protobuf/internal/message_factory_test.py
new file mode 100644
index 00000000..0bc9be99
--- /dev/null
+++ b/python/google/protobuf/internal/message_factory_test.py
@@ -0,0 +1,113 @@
+#! /usr/bin/python
+#
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Tests for google.protobuf.message_factory."""
+
+__author__ = 'matthewtoia@google.com (Matt Toia)'
+
+import unittest
+from google.protobuf import descriptor_pb2
+from google.protobuf.internal import factory_test1_pb2
+from google.protobuf.internal import factory_test2_pb2
+from google.protobuf import descriptor_database
+from google.protobuf import descriptor_pool
+from google.protobuf import message_factory
+
+
+class MessageFactoryTest(unittest.TestCase):
+
+  def setUp(self):
+    self.factory_test1_fd = descriptor_pb2.FileDescriptorProto.FromString(
+        factory_test1_pb2.DESCRIPTOR.serialized_pb)
+    self.factory_test2_fd = descriptor_pb2.FileDescriptorProto.FromString(
+        factory_test2_pb2.DESCRIPTOR.serialized_pb)
+
+  def _ExerciseDynamicClass(self, cls):
+    msg = cls()
+    msg.mandatory = 42
+    msg.nested_factory_2_enum = 0
+    msg.nested_factory_2_message.value = 'nested message value'
+    msg.factory_1_message.factory_1_enum = 1
+    msg.factory_1_message.nested_factory_1_enum = 0
+    msg.factory_1_message.nested_factory_1_message.value = (
+        'nested message value')
+    msg.factory_1_message.scalar_value = 22
+    msg.factory_1_message.list_value.extend(['one', 'two', 'three'])
+    msg.factory_1_message.list_value.append('four')
+    msg.factory_1_enum = 1
+    msg.nested_factory_1_enum = 0
+    msg.nested_factory_1_message.value = 'nested message value'
+    msg.circular_message.mandatory = 1
+    msg.circular_message.circular_message.mandatory = 2
+    msg.circular_message.scalar_value = 'one deep'
+    msg.scalar_value = 'zero deep'
+    msg.list_value.extend(['four', 'three', 'two'])
+    msg.list_value.append('one')
+    msg.grouped.add()
+    msg.grouped[0].part_1 = 'hello'
+    msg.grouped[0].part_2 = 'world'
+    msg.grouped.add(part_1='testing', part_2='123')
+    msg.loop.loop.mandatory = 2
+    msg.loop.loop.loop.loop.mandatory = 4
+    serialized = msg.SerializeToString()
+    converted = factory_test2_pb2.Factory2Message.FromString(serialized)
+    reserialized = converted.SerializeToString()
+    self.assertEquals(serialized, reserialized)
+    result = cls.FromString(reserialized)
+    self.assertEquals(msg, result)
+
+  def testGetPrototype(self):
+    db = descriptor_database.DescriptorDatabase()
+    pool = descriptor_pool.DescriptorPool(db)
+    db.Add(self.factory_test1_fd)
+    db.Add(self.factory_test2_fd)
+    factory = message_factory.MessageFactory()
+    cls = factory.GetPrototype(pool.FindMessageTypeByName(
+        'net.proto2.python.internal.Factory2Message'))
+    self.assertIsNot(cls, factory_test2_pb2.Factory2Message)
+    self._ExerciseDynamicClass(cls)
+    cls2 = factory.GetPrototype(pool.FindMessageTypeByName(
+        'net.proto2.python.internal.Factory2Message'))
+    self.assertIs(cls, cls2)
+
+  def testGetMessages(self):
+    messages = message_factory.GetMessages([self.factory_test2_fd,
+                                            self.factory_test1_fd])
+    self.assertContainsSubset(
+        ['net.proto2.python.internal.Factory2Message',
+         'net.proto2.python.internal.Factory1Message'],
+        messages.keys())
+    self._ExerciseDynamicClass(
+        messages['net.proto2.python.internal.Factory2Message'])
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/python/google/protobuf/internal/message_test.py b/python/google/protobuf/internal/message_test.py
index 65174373..53e9d507 100755
--- a/python/google/protobuf/internal/message_test.py
+++ b/python/google/protobuf/internal/message_test.py
@@ -45,10 +45,15 @@ __author__ = 'gps@google.com (Gregory P. Smith)'
 
 import copy
 import math
+import operator
+import pickle
+
 import unittest
 from google.protobuf import unittest_import_pb2
 from google.protobuf import unittest_pb2
+from google.protobuf.internal import api_implementation
 from google.protobuf.internal import test_util
+from google.protobuf import message
 
 # Python pre-2.6 does not have isinf() or isnan() functions, so we have
 # to provide our own.
@@ -70,9 +75,9 @@ class MessageTest(unittest.TestCase):
     golden_message = unittest_pb2.TestAllTypes()
     golden_message.ParseFromString(golden_data)
     test_util.ExpectAllFieldsSet(self, golden_message)
-    self.assertTrue(golden_message.SerializeToString() == golden_data)
+    self.assertEqual(golden_data, golden_message.SerializeToString())
     golden_copy = copy.deepcopy(golden_message)
-    self.assertTrue(golden_copy.SerializeToString() == golden_data)
+    self.assertEqual(golden_data, golden_copy.SerializeToString())
 
   def testGoldenExtensions(self):
     golden_data = test_util.GoldenFile('golden_message').read()
@@ -81,9 +86,9 @@ class MessageTest(unittest.TestCase):
     all_set = unittest_pb2.TestAllExtensions()
     test_util.SetAllExtensions(all_set)
     self.assertEquals(all_set, golden_message)
-    self.assertTrue(golden_message.SerializeToString() == golden_data)
+    self.assertEqual(golden_data, golden_message.SerializeToString())
     golden_copy = copy.deepcopy(golden_message)
-    self.assertTrue(golden_copy.SerializeToString() == golden_data)
+    self.assertEqual(golden_data, golden_copy.SerializeToString())
 
   def testGoldenPackedMessage(self):
     golden_data = test_util.GoldenFile('golden_packed_fields_message').read()
@@ -92,9 +97,9 @@ class MessageTest(unittest.TestCase):
     all_set = unittest_pb2.TestPackedTypes()
     test_util.SetAllPackedFields(all_set)
     self.assertEquals(all_set, golden_message)
-    self.assertTrue(all_set.SerializeToString() == golden_data)
+    self.assertEqual(golden_data, all_set.SerializeToString())
     golden_copy = copy.deepcopy(golden_message)
-    self.assertTrue(golden_copy.SerializeToString() == golden_data)
+    self.assertEqual(golden_data, golden_copy.SerializeToString())
 
   def testGoldenPackedExtensions(self):
     golden_data = test_util.GoldenFile('golden_packed_fields_message').read()
@@ -103,9 +108,28 @@ class MessageTest(unittest.TestCase):
     all_set = unittest_pb2.TestPackedExtensions()
     test_util.SetAllPackedExtensions(all_set)
     self.assertEquals(all_set, golden_message)
-    self.assertTrue(all_set.SerializeToString() == golden_data)
+    self.assertEqual(golden_data, all_set.SerializeToString())
     golden_copy = copy.deepcopy(golden_message)
-    self.assertTrue(golden_copy.SerializeToString() == golden_data)
+    self.assertEqual(golden_data, golden_copy.SerializeToString())
+
+  def testPickleSupport(self):
+    golden_data = test_util.GoldenFile('golden_message').read()
+    golden_message = unittest_pb2.TestAllTypes()
+    golden_message.ParseFromString(golden_data)
+    pickled_message = pickle.dumps(golden_message)
+
+    unpickled_message = pickle.loads(pickled_message)
+    self.assertEquals(unpickled_message, golden_message)
+
+  def testPickleIncompleteProto(self):
+    golden_message = unittest_pb2.TestRequired(a=1)
+    pickled_message = pickle.dumps(golden_message)
+
+    unpickled_message = pickle.loads(pickled_message)
+    self.assertEquals(unpickled_message, golden_message)
+    self.assertEquals(unpickled_message.a, 1)
+    # This is still an incomplete proto - so serializing should fail
+    self.assertRaises(message.EncodeError, unpickled_message.SerializeToString)
 
   def testPositiveInfinity(self):
     golden_data = ('\x5D\x00\x00\x80\x7F'
@@ -118,7 +142,7 @@ class MessageTest(unittest.TestCase):
     self.assertTrue(IsPosInf(golden_message.optional_double))
     self.assertTrue(IsPosInf(golden_message.repeated_float[0]))
     self.assertTrue(IsPosInf(golden_message.repeated_double[0]))
-    self.assertTrue(golden_message.SerializeToString() == golden_data)
+    self.assertEqual(golden_data, golden_message.SerializeToString())
 
   def testNegativeInfinity(self):
     golden_data = ('\x5D\x00\x00\x80\xFF'
@@ -131,7 +155,7 @@ class MessageTest(unittest.TestCase):
     self.assertTrue(IsNegInf(golden_message.optional_double))
     self.assertTrue(IsNegInf(golden_message.repeated_float[0]))
     self.assertTrue(IsNegInf(golden_message.repeated_double[0]))
-    self.assertTrue(golden_message.SerializeToString() == golden_data)
+    self.assertEqual(golden_data, golden_message.SerializeToString())
 
   def testNotANumber(self):
     golden_data = ('\x5D\x00\x00\xC0\x7F'
@@ -144,7 +168,18 @@ class MessageTest(unittest.TestCase):
     self.assertTrue(isnan(golden_message.optional_double))
     self.assertTrue(isnan(golden_message.repeated_float[0]))
     self.assertTrue(isnan(golden_message.repeated_double[0]))
-    self.assertTrue(golden_message.SerializeToString() == golden_data)
+
+    # The protocol buffer may serialize to any one of multiple different
+    # representations of a NaN.  Rather than verify a specific representation,
+    # verify the serialized string can be converted into a correctly
+    # behaving protocol buffer.
+    serialized = golden_message.SerializeToString()
+    message = unittest_pb2.TestAllTypes()
+    message.ParseFromString(serialized)
+    self.assertTrue(isnan(message.optional_float))
+    self.assertTrue(isnan(message.optional_double))
+    self.assertTrue(isnan(message.repeated_float[0]))
+    self.assertTrue(isnan(message.repeated_double[0]))
 
   def testPositiveInfinityPacked(self):
     golden_data = ('\xA2\x06\x04\x00\x00\x80\x7F'
@@ -153,7 +188,7 @@ class MessageTest(unittest.TestCase):
     golden_message.ParseFromString(golden_data)
     self.assertTrue(IsPosInf(golden_message.packed_float[0]))
     self.assertTrue(IsPosInf(golden_message.packed_double[0]))
-    self.assertTrue(golden_message.SerializeToString() == golden_data)
+    self.assertEqual(golden_data, golden_message.SerializeToString())
 
   def testNegativeInfinityPacked(self):
     golden_data = ('\xA2\x06\x04\x00\x00\x80\xFF'
@@ -162,7 +197,7 @@ class MessageTest(unittest.TestCase):
     golden_message.ParseFromString(golden_data)
     self.assertTrue(IsNegInf(golden_message.packed_float[0]))
     self.assertTrue(IsNegInf(golden_message.packed_double[0]))
-    self.assertTrue(golden_message.SerializeToString() == golden_data)
+    self.assertEqual(golden_data, golden_message.SerializeToString())
 
   def testNotANumberPacked(self):
     golden_data = ('\xA2\x06\x04\x00\x00\xC0\x7F'
@@ -171,7 +206,12 @@ class MessageTest(unittest.TestCase):
     golden_message.ParseFromString(golden_data)
     self.assertTrue(isnan(golden_message.packed_float[0]))
     self.assertTrue(isnan(golden_message.packed_double[0]))
-    self.assertTrue(golden_message.SerializeToString() == golden_data)
+
+    serialized = golden_message.SerializeToString()
+    message = unittest_pb2.TestPackedTypes()
+    message.ParseFromString(serialized)
+    self.assertTrue(isnan(message.packed_float[0]))
+    self.assertTrue(isnan(message.packed_double[0]))
 
   def testExtremeFloatValues(self):
     message = unittest_pb2.TestAllTypes()
@@ -218,7 +258,7 @@ class MessageTest(unittest.TestCase):
     message.ParseFromString(message.SerializeToString())
     self.assertTrue(message.optional_float == -kMostNegExponentOneSigBit)
 
-  def testExtremeFloatValues(self):
+  def testExtremeDoubleValues(self):
     message = unittest_pb2.TestAllTypes()
 
     # Most positive exponent, no significand bits set.
@@ -338,6 +378,117 @@ class MessageTest(unittest.TestCase):
     self.assertEqual(message.repeated_nested_message[4].bb, 5)
     self.assertEqual(message.repeated_nested_message[5].bb, 6)
 
+  def testRepeatedCompositeFieldSortArguments(self):
+    """Check sorting a repeated composite field using list.sort() arguments."""
+    message = unittest_pb2.TestAllTypes()
+
+    get_bb = operator.attrgetter('bb')
+    cmp_bb = lambda a, b: cmp(a.bb, b.bb)
+    message.repeated_nested_message.add().bb = 1
+    message.repeated_nested_message.add().bb = 3
+    message.repeated_nested_message.add().bb = 2
+    message.repeated_nested_message.add().bb = 6
+    message.repeated_nested_message.add().bb = 5
+    message.repeated_nested_message.add().bb = 4
+    message.repeated_nested_message.sort(key=get_bb)
+    self.assertEqual([k.bb for k in message.repeated_nested_message],
+                     [1, 2, 3, 4, 5, 6])
+    message.repeated_nested_message.sort(key=get_bb, reverse=True)
+    self.assertEqual([k.bb for k in message.repeated_nested_message],
+                     [6, 5, 4, 3, 2, 1])
+    message.repeated_nested_message.sort(sort_function=cmp_bb)
+    self.assertEqual([k.bb for k in message.repeated_nested_message],
+                     [1, 2, 3, 4, 5, 6])
+    message.repeated_nested_message.sort(cmp=cmp_bb, reverse=True)
+    self.assertEqual([k.bb for k in message.repeated_nested_message],
+                     [6, 5, 4, 3, 2, 1])
+
+  def testRepeatedScalarFieldSortArguments(self):
+    """Check sorting a scalar field using list.sort() arguments."""
+    message = unittest_pb2.TestAllTypes()
+
+    abs_cmp = lambda a, b: cmp(abs(a), abs(b))
+    message.repeated_int32.append(-3)
+    message.repeated_int32.append(-2)
+    message.repeated_int32.append(-1)
+    message.repeated_int32.sort(key=abs)
+    self.assertEqual(list(message.repeated_int32), [-1, -2, -3])
+    message.repeated_int32.sort(key=abs, reverse=True)
+    self.assertEqual(list(message.repeated_int32), [-3, -2, -1])
+    message.repeated_int32.sort(sort_function=abs_cmp)
+    self.assertEqual(list(message.repeated_int32), [-1, -2, -3])
+    message.repeated_int32.sort(cmp=abs_cmp, reverse=True)
+    self.assertEqual(list(message.repeated_int32), [-3, -2, -1])
+
+    len_cmp = lambda a, b: cmp(len(a), len(b))
+    message.repeated_string.append('aaa')
+    message.repeated_string.append('bb')
+    message.repeated_string.append('c')
+    message.repeated_string.sort(key=len)
+    self.assertEqual(list(message.repeated_string), ['c', 'bb', 'aaa'])
+    message.repeated_string.sort(key=len, reverse=True)
+    self.assertEqual(list(message.repeated_string), ['aaa', 'bb', 'c'])
+    message.repeated_string.sort(sort_function=len_cmp)
+    self.assertEqual(list(message.repeated_string), ['c', 'bb', 'aaa'])
+    message.repeated_string.sort(cmp=len_cmp, reverse=True)
+    self.assertEqual(list(message.repeated_string), ['aaa', 'bb', 'c'])
+
+  def testParsingMerge(self):
+    """Check the merge behavior when a required or optional field appears
+    multiple times in the input."""
+    messages = [
+        unittest_pb2.TestAllTypes(),
+        unittest_pb2.TestAllTypes(),
+        unittest_pb2.TestAllTypes() ]
+    messages[0].optional_int32 = 1
+    messages[1].optional_int64 = 2
+    messages[2].optional_int32 = 3
+    messages[2].optional_string = 'hello'
+
+    merged_message = unittest_pb2.TestAllTypes()
+    merged_message.optional_int32 = 3
+    merged_message.optional_int64 = 2
+    merged_message.optional_string = 'hello'
+
+    generator = unittest_pb2.TestParsingMerge.RepeatedFieldsGenerator()
+    generator.field1.extend(messages)
+    generator.field2.extend(messages)
+    generator.field3.extend(messages)
+    generator.ext1.extend(messages)
+    generator.ext2.extend(messages)
+    generator.group1.add().field1.MergeFrom(messages[0])
+    generator.group1.add().field1.MergeFrom(messages[1])
+    generator.group1.add().field1.MergeFrom(messages[2])
+    generator.group2.add().field1.MergeFrom(messages[0])
+    generator.group2.add().field1.MergeFrom(messages[1])
+    generator.group2.add().field1.MergeFrom(messages[2])
+
+    data = generator.SerializeToString()
+    parsing_merge = unittest_pb2.TestParsingMerge()
+    parsing_merge.ParseFromString(data)
+
+    # Required and optional fields should be merged.
+    self.assertEqual(parsing_merge.required_all_types, merged_message)
+    self.assertEqual(parsing_merge.optional_all_types, merged_message)
+    self.assertEqual(parsing_merge.optionalgroup.optional_group_all_types,
+                     merged_message)
+    self.assertEqual(parsing_merge.Extensions[
+                     unittest_pb2.TestParsingMerge.optional_ext],
+                     merged_message)
+
+    # Repeated fields should not be merged.
+    self.assertEqual(len(parsing_merge.repeated_all_types), 3)
+    self.assertEqual(len(parsing_merge.repeatedgroup), 3)
+    self.assertEqual(len(parsing_merge.Extensions[
+        unittest_pb2.TestParsingMerge.repeated_ext]), 3)
+
+
+  def testSortEmptyRepeatedCompositeContainer(self):
+    """Exercise a scenario that has led to segfaults in the past.
+    """
+    m = unittest_pb2.TestAllTypes()
+    m.repeated_nested_message.sort()
+
 
 if __name__ == '__main__':
   unittest.main()
diff --git a/python/google/protobuf/internal/more_extensions_dynamic.proto b/python/google/protobuf/internal/more_extensions_dynamic.proto
new file mode 100644
index 00000000..df98ac4b
--- /dev/null
+++ b/python/google/protobuf/internal/more_extensions_dynamic.proto
@@ -0,0 +1,49 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: jasonh@google.com (Jason Hsueh)
+//
+// This file is used to test a corner case in the CPP implementation where the
+// generated C++ type is available for the extendee, but the extension is
+// defined in a file whose C++ type is not in the binary.
+
+
+import "google/protobuf/internal/more_extensions.proto";
+
+package google.protobuf.internal;
+
+message DynamicMessageType {
+  optional int32 a = 1;
+}
+
+extend ExtendedMessage {
+  optional int32 dynamic_int32_extension = 100;
+  optional DynamicMessageType dynamic_message_extension = 101;
+}
diff --git a/python/google/protobuf/internal/python_message.py b/python/google/protobuf/internal/python_message.py
index 66fca918..4bea57ac 100755
--- a/python/google/protobuf/internal/python_message.py
+++ b/python/google/protobuf/internal/python_message.py
@@ -54,6 +54,7 @@ try:
   from cStringIO import StringIO
 except ImportError:
   from StringIO import StringIO
+import copy_reg
 import struct
 import weakref
 
@@ -61,6 +62,7 @@ import weakref
 from google.protobuf.internal import containers
 from google.protobuf.internal import decoder
 from google.protobuf.internal import encoder
+from google.protobuf.internal import enum_type_wrapper
 from google.protobuf.internal import message_listener as message_listener_mod
 from google.protobuf.internal import type_checkers
 from google.protobuf.internal import wire_format
@@ -71,9 +73,10 @@ from google.protobuf import text_format
 _FieldDescriptor = descriptor_mod.FieldDescriptor
 
 
-def NewMessage(descriptor, dictionary):
+def NewMessage(bases, descriptor, dictionary):
   _AddClassAttributesForNestedExtensions(descriptor, dictionary)
   _AddSlots(descriptor, dictionary)
+  return bases
 
 
 def InitMessage(descriptor, cls):
@@ -96,6 +99,7 @@ def InitMessage(descriptor, cls):
   _AddStaticMethods(cls)
   _AddMessageMethods(descriptor, cls)
   _AddPrivateHelperMethods(cls)
+  copy_reg.pickle(cls, lambda obj: (cls, (), obj.__getstate__()))
 
 
 # Stateless helpers for GeneratedProtocolMessageType below.
@@ -145,6 +149,10 @@ def _VerifyExtensionHandle(message, extension_handle):
   if not extension_handle.is_extension:
     raise KeyError('"%s" is not an extension.' % extension_handle.full_name)
 
+  if not extension_handle.containing_type:
+    raise KeyError('"%s" is missing a containing_type.'
+                   % extension_handle.full_name)
+
   if extension_handle.containing_type is not message.DESCRIPTOR:
     raise KeyError('Extension "%s" extends message type "%s", but this '
                    'message is of type "%s".' %
@@ -164,6 +172,7 @@ def _AddSlots(message_descriptor, dictionary):
   dictionary['__slots__'] = ['_cached_byte_size',
                              '_cached_byte_size_dirty',
                              '_fields',
+                             '_unknown_fields',
                              '_is_present_in_parent',
                              '_listener',
                              '_listener_for_children',
@@ -224,11 +233,14 @@ def _AddClassAttributesForNestedExtensions(descriptor, dictionary):
 def _AddEnumValues(descriptor, cls):
   """Sets class-level attributes for all enum fields defined in this message.
 
+  Also exporting a class-level object that can name enum values.
+
   Args:
     descriptor: Descriptor object for this message type.
     cls: Class we're constructing for this message type.
   """
   for enum_type in descriptor.enum_types:
+    setattr(cls, enum_type.name, enum_type_wrapper.EnumTypeWrapper(enum_type))
     for enum_value in enum_type.values:
       setattr(cls, enum_value.name, enum_value.number)
 
@@ -248,7 +260,7 @@ def _DefaultValueConstructorForField(field):
   """
 
   if field.label == _FieldDescriptor.LABEL_REPEATED:
-    if field.default_value != []:
+    if field.has_default_value and field.default_value != []:
       raise ValueError('Repeated field default value not empty list: %s' % (
           field.default_value))
     if field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE:
@@ -276,6 +288,8 @@ def _DefaultValueConstructorForField(field):
     return MakeSubMessageDefault
 
   def MakeScalarDefault(message):
+    # TODO(protobuf-team): This may be broken since there may not be
+    # default_value.  Combine with has_default_value somehow.
     return field.default_value
   return MakeScalarDefault
 
@@ -287,6 +301,9 @@ def _AddInitMethod(message_descriptor, cls):
     self._cached_byte_size = 0
     self._cached_byte_size_dirty = len(kwargs) > 0
     self._fields = {}
+    # _unknown_fields is () when empty for efficiency, and will be turned into
+    # a list if fields are added.
+    self._unknown_fields = ()
     self._is_present_in_parent = False
     self._listener = message_listener_mod.NullMessageListener()
     self._listener_for_children = _Listener(self)
@@ -428,6 +445,8 @@ def _AddPropertiesForNonRepeatedScalarField(field, cls):
   valid_values = set()
 
   def getter(self):
+    # TODO(protobuf-team): This may be broken since there may not be
+    # default_value.  Combine with has_default_value somehow.
     return self._fields.get(field, default_value)
   getter.__module__ = None
   getter.__doc__ = 'Getter for %s.' % proto_field_name
@@ -462,13 +481,18 @@ def _AddPropertiesForNonRepeatedCompositeField(field, cls):
   # for non-repeated scalars.
   proto_field_name = field.name
   property_name = _PropertyName(proto_field_name)
+
+  # TODO(komarek): Can anyone explain to me why we cache the message_type this
+  # way, instead of referring to field.message_type inside of getter(self)?
+  # What if someone sets message_type later on (which makes for simpler
+  # dyanmic proto descriptor and class creation code).
   message_type = field.message_type
 
   def getter(self):
     field_value = self._fields.get(field)
     if field_value is None:
       # Construct a new object to represent this field.
-      field_value = message_type._concrete_class()
+      field_value = message_type._concrete_class()  # use field.message_type?
       field_value._SetListener(self._listener_for_children)
 
       # Atomically check if another thread has preempted us and, if not, swap
@@ -620,6 +644,7 @@ def _AddClearMethod(message_descriptor, cls):
   def Clear(self):
     # Clear fields.
     self._fields = {}
+    self._unknown_fields = ()
     self._Modified()
   cls.Clear = Clear
 
@@ -649,7 +674,16 @@ def _AddEqualsMethod(message_descriptor, cls):
     if self is other:
       return True
 
-    return self.ListFields() == other.ListFields()
+    if not self.ListFields() == other.ListFields():
+      return False
+
+    # Sort unknown fields because their order shouldn't affect equality test.
+    unknown_fields = list(self._unknown_fields)
+    unknown_fields.sort()
+    other_unknown_fields = list(other._unknown_fields)
+    other_unknown_fields.sort()
+
+    return unknown_fields == other_unknown_fields
 
   cls.__eq__ = __eq__
 
@@ -710,6 +744,9 @@ def _AddByteSizeMethod(message_descriptor, cls):
     for field_descriptor, field_value in self.ListFields():
       size += field_descriptor._sizer(field_value)
 
+    for tag_bytes, value_bytes in self._unknown_fields:
+      size += len(tag_bytes) + len(value_bytes)
+
     self._cached_byte_size = size
     self._cached_byte_size_dirty = False
     self._listener_for_children.dirty = False
@@ -726,8 +763,8 @@ def _AddSerializeToStringMethod(message_descriptor, cls):
     errors = []
     if not self.IsInitialized():
       raise message_mod.EncodeError(
-          'Message is missing required fields: ' +
-          ','.join(self.FindInitializationErrors()))
+          'Message %s is missing required fields: %s' % (
+          self.DESCRIPTOR.full_name, ','.join(self.FindInitializationErrors())))
     return self.SerializePartialToString()
   cls.SerializeToString = SerializeToString
 
@@ -744,6 +781,9 @@ def _AddSerializePartialToStringMethod(message_descriptor, cls):
   def InternalSerialize(self, write_bytes):
     for field_descriptor, field_value in self.ListFields():
       field_descriptor._encoder(write_bytes, field_value)
+    for tag_bytes, value_bytes in self._unknown_fields:
+      write_bytes(tag_bytes)
+      write_bytes(value_bytes)
   cls._InternalSerialize = InternalSerialize
 
 
@@ -770,13 +810,18 @@ def _AddMergeFromStringMethod(message_descriptor, cls):
   def InternalParse(self, buffer, pos, end):
     self._Modified()
     field_dict = self._fields
+    unknown_field_list = self._unknown_fields
     while pos != end:
       (tag_bytes, new_pos) = local_ReadTag(buffer, pos)
       field_decoder = decoders_by_tag.get(tag_bytes)
       if field_decoder is None:
+        value_start_pos = new_pos
         new_pos = local_SkipField(buffer, new_pos, end, tag_bytes)
         if new_pos == -1:
           return pos
+        if not unknown_field_list:
+          unknown_field_list = self._unknown_fields = []
+        unknown_field_list.append((tag_bytes, buffer[value_start_pos:new_pos]))
         pos = new_pos
       else:
         pos = field_decoder(buffer, new_pos, end, self, field_dict)
@@ -873,7 +918,8 @@ def _AddMergeFromMethod(cls):
   def MergeFrom(self, msg):
     if not isinstance(msg, cls):
       raise TypeError(
-          "Parameter to MergeFrom() must be instance of same class.")
+          "Parameter to MergeFrom() must be instance of same class: "
+          "expected %s got %s." % (cls.__name__, type(msg).__name__))
 
     assert msg is not self
     self._Modified()
@@ -898,6 +944,12 @@ def _AddMergeFromMethod(cls):
           field_value.MergeFrom(value)
       else:
         self._fields[field] = value
+
+    if msg._unknown_fields:
+      if not self._unknown_fields:
+        self._unknown_fields = []
+      self._unknown_fields.extend(msg._unknown_fields)
+
   cls.MergeFrom = MergeFrom
 
 
diff --git a/python/google/protobuf/internal/reflection_cpp_generated_test.py b/python/google/protobuf/internal/reflection_cpp_generated_test.py
new file mode 100755
index 00000000..2a0a5124
--- /dev/null
+++ b/python/google/protobuf/internal/reflection_cpp_generated_test.py
@@ -0,0 +1,91 @@
+#! /usr/bin/python
+# -*- coding: utf-8 -*-
+#
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Unittest for reflection.py, which tests the generated C++ implementation."""
+
+__author__ = 'jasonh@google.com (Jason Hsueh)'
+
+import os
+os.environ['PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION'] = 'cpp'
+
+import unittest
+from google.protobuf.internal import api_implementation
+from google.protobuf.internal import more_extensions_dynamic_pb2
+from google.protobuf.internal import more_extensions_pb2
+from google.protobuf.internal.reflection_test import *
+
+
+class ReflectionCppTest(unittest.TestCase):
+  def testImplementationSetting(self):
+    self.assertEqual('cpp', api_implementation.Type())
+
+  def testExtensionOfGeneratedTypeInDynamicFile(self):
+    """Tests that a file built dynamically can extend a generated C++ type.
+
+    The C++ implementation uses a DescriptorPool that has the generated
+    DescriptorPool as an underlay. Typically, a type can only find
+    extensions in its own pool. With the python C-extension, the generated C++
+    extendee may be available, but not the extension. This tests that the
+    C-extension implements the correct special handling to make such extensions
+    available.
+    """
+    pb1 = more_extensions_pb2.ExtendedMessage()
+    # Test that basic accessors work.
+    self.assertFalse(
+        pb1.HasExtension(more_extensions_dynamic_pb2.dynamic_int32_extension))
+    self.assertFalse(
+        pb1.HasExtension(more_extensions_dynamic_pb2.dynamic_message_extension))
+    pb1.Extensions[more_extensions_dynamic_pb2.dynamic_int32_extension] = 17
+    pb1.Extensions[more_extensions_dynamic_pb2.dynamic_message_extension].a = 24
+    self.assertTrue(
+        pb1.HasExtension(more_extensions_dynamic_pb2.dynamic_int32_extension))
+    self.assertTrue(
+        pb1.HasExtension(more_extensions_dynamic_pb2.dynamic_message_extension))
+
+    # Now serialize the data and parse to a new message.
+    pb2 = more_extensions_pb2.ExtendedMessage()
+    pb2.MergeFromString(pb1.SerializeToString())
+
+    self.assertTrue(
+        pb2.HasExtension(more_extensions_dynamic_pb2.dynamic_int32_extension))
+    self.assertTrue(
+        pb2.HasExtension(more_extensions_dynamic_pb2.dynamic_message_extension))
+    self.assertEqual(
+        17, pb2.Extensions[more_extensions_dynamic_pb2.dynamic_int32_extension])
+    self.assertEqual(
+        24,
+        pb2.Extensions[more_extensions_dynamic_pb2.dynamic_message_extension].a)
+
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/python/google/protobuf/internal/reflection_test.py b/python/google/protobuf/internal/reflection_test.py
index 7b9d3398..ed286461 100755
--- a/python/google/protobuf/internal/reflection_test.py
+++ b/python/google/protobuf/internal/reflection_test.py
@@ -37,6 +37,7 @@ pure-Python protocol compiler.
 
 __author__ = 'robinson@google.com (Will Robinson)'
 
+import gc
 import operator
 import struct
 
@@ -318,15 +319,6 @@ class ReflectionTest(unittest.TestCase):
       # ...and ensure that the scalar field has returned to its default.
       self.assertEqual(0, getattr(composite_field, scalar_field_name))
 
-      # Finally, ensure that modifications to the old composite field object
-      # don't have any effect on the parent. Possible only with the pure-python
-      # implementation of the API.
-      #
-      # (NOTE that when we clear the composite field in the parent, we actually
-      # don't recursively clear down the tree.  Instead, we just disconnect the
-      # cleared composite from the tree.)
-      if api_implementation.Type() != 'python':
-        return
       self.assertTrue(old_composite_field is not composite_field)
       setattr(old_composite_field, scalar_field_name, new_val)
       self.assertTrue(not composite_field.HasField(scalar_field_name))
@@ -348,8 +340,6 @@ class ReflectionTest(unittest.TestCase):
     nested.bb = 23
 
   def testDisconnectingNestedMessageBeforeSettingField(self):
-    if api_implementation.Type() != 'python':
-      return
     proto = unittest_pb2.TestAllTypes()
     nested = proto.optional_nested_message
     proto.ClearField('optional_nested_message')  # Should disconnect from parent
@@ -358,6 +348,64 @@ class ReflectionTest(unittest.TestCase):
     self.assertTrue(not proto.HasField('optional_nested_message'))
     self.assertEqual(0, proto.optional_nested_message.bb)
 
+  def testGetDefaultMessageAfterDisconnectingDefaultMessage(self):
+    proto = unittest_pb2.TestAllTypes()
+    nested = proto.optional_nested_message
+    proto.ClearField('optional_nested_message')
+    del proto
+    del nested
+    # Force a garbage collect so that the underlying CMessages are freed along
+    # with the Messages they point to. This is to make sure we're not deleting
+    # default message instances.
+    gc.collect()
+    proto = unittest_pb2.TestAllTypes()
+    nested = proto.optional_nested_message
+
+  def testDisconnectingNestedMessageAfterSettingField(self):
+    proto = unittest_pb2.TestAllTypes()
+    nested = proto.optional_nested_message
+    nested.bb = 5
+    self.assertTrue(proto.HasField('optional_nested_message'))
+    proto.ClearField('optional_nested_message')  # Should disconnect from parent
+    self.assertEqual(5, nested.bb)
+    self.assertEqual(0, proto.optional_nested_message.bb)
+    self.assertTrue(nested is not proto.optional_nested_message)
+    nested.bb = 23
+    self.assertTrue(not proto.HasField('optional_nested_message'))
+    self.assertEqual(0, proto.optional_nested_message.bb)
+
+  def testDisconnectingNestedMessageBeforeGettingField(self):
+    proto = unittest_pb2.TestAllTypes()
+    self.assertTrue(not proto.HasField('optional_nested_message'))
+    proto.ClearField('optional_nested_message')
+    self.assertTrue(not proto.HasField('optional_nested_message'))
+
+  def testDisconnectingNestedMessageAfterMerge(self):
+    # This test exercises the code path that does not use ReleaseMessage().
+    # The underlying fear is that if we use ReleaseMessage() incorrectly,
+    # we will have memory leaks.  It's hard to check that that doesn't happen,
+    # but at least we can exercise that code path to make sure it works.
+    proto1 = unittest_pb2.TestAllTypes()
+    proto2 = unittest_pb2.TestAllTypes()
+    proto2.optional_nested_message.bb = 5
+    proto1.MergeFrom(proto2)
+    self.assertTrue(proto1.HasField('optional_nested_message'))
+    proto1.ClearField('optional_nested_message')
+    self.assertTrue(not proto1.HasField('optional_nested_message'))
+
+  def testDisconnectingLazyNestedMessage(self):
+    # This test exercises releasing a nested message that is lazy. This test
+    # only exercises real code in the C++ implementation as Python does not
+    # support lazy parsing, but the current C++ implementation results in
+    # memory corruption and a crash.
+    if api_implementation.Type() != 'python':
+      return
+    proto = unittest_pb2.TestAllTypes()
+    proto.optional_lazy_message.bb = 5
+    proto.ClearField('optional_lazy_message')
+    del proto
+    gc.collect()
+
   def testHasBitsWhenModifyingRepeatedFields(self):
     # Test nesting when we add an element to a repeated field in a submessage.
     proto = unittest_pb2.TestNestedMessageHasBits()
@@ -635,6 +683,77 @@ class ReflectionTest(unittest.TestCase):
     self.assertEqual(3, proto.BAZ)
     self.assertEqual(3, unittest_pb2.TestAllTypes.BAZ)
 
+  def testEnum_Name(self):
+    self.assertEqual('FOREIGN_FOO',
+                     unittest_pb2.ForeignEnum.Name(unittest_pb2.FOREIGN_FOO))
+    self.assertEqual('FOREIGN_BAR',
+                     unittest_pb2.ForeignEnum.Name(unittest_pb2.FOREIGN_BAR))
+    self.assertEqual('FOREIGN_BAZ',
+                     unittest_pb2.ForeignEnum.Name(unittest_pb2.FOREIGN_BAZ))
+    self.assertRaises(ValueError,
+                      unittest_pb2.ForeignEnum.Name, 11312)
+
+    proto = unittest_pb2.TestAllTypes()
+    self.assertEqual('FOO',
+                     proto.NestedEnum.Name(proto.FOO))
+    self.assertEqual('FOO',
+                     unittest_pb2.TestAllTypes.NestedEnum.Name(proto.FOO))
+    self.assertEqual('BAR',
+                     proto.NestedEnum.Name(proto.BAR))
+    self.assertEqual('BAR',
+                     unittest_pb2.TestAllTypes.NestedEnum.Name(proto.BAR))
+    self.assertEqual('BAZ',
+                     proto.NestedEnum.Name(proto.BAZ))
+    self.assertEqual('BAZ',
+                     unittest_pb2.TestAllTypes.NestedEnum.Name(proto.BAZ))
+    self.assertRaises(ValueError,
+                      proto.NestedEnum.Name, 11312)
+    self.assertRaises(ValueError,
+                      unittest_pb2.TestAllTypes.NestedEnum.Name, 11312)
+
+  def testEnum_Value(self):
+    self.assertEqual(unittest_pb2.FOREIGN_FOO,
+                     unittest_pb2.ForeignEnum.Value('FOREIGN_FOO'))
+    self.assertEqual(unittest_pb2.FOREIGN_BAR,
+                     unittest_pb2.ForeignEnum.Value('FOREIGN_BAR'))
+    self.assertEqual(unittest_pb2.FOREIGN_BAZ,
+                     unittest_pb2.ForeignEnum.Value('FOREIGN_BAZ'))
+    self.assertRaises(ValueError,
+                      unittest_pb2.ForeignEnum.Value, 'FO')
+
+    proto = unittest_pb2.TestAllTypes()
+    self.assertEqual(proto.FOO,
+                     proto.NestedEnum.Value('FOO'))
+    self.assertEqual(proto.FOO,
+                     unittest_pb2.TestAllTypes.NestedEnum.Value('FOO'))
+    self.assertEqual(proto.BAR,
+                     proto.NestedEnum.Value('BAR'))
+    self.assertEqual(proto.BAR,
+                     unittest_pb2.TestAllTypes.NestedEnum.Value('BAR'))
+    self.assertEqual(proto.BAZ,
+                     proto.NestedEnum.Value('BAZ'))
+    self.assertEqual(proto.BAZ,
+                     unittest_pb2.TestAllTypes.NestedEnum.Value('BAZ'))
+    self.assertRaises(ValueError,
+                      proto.NestedEnum.Value, 'Foo')
+    self.assertRaises(ValueError,
+                      unittest_pb2.TestAllTypes.NestedEnum.Value, 'Foo')
+
+  def testEnum_KeysAndValues(self):
+    self.assertEqual(['FOREIGN_FOO', 'FOREIGN_BAR', 'FOREIGN_BAZ'],
+                     unittest_pb2.ForeignEnum.keys())
+    self.assertEqual([4, 5, 6],
+                     unittest_pb2.ForeignEnum.values())
+    self.assertEqual([('FOREIGN_FOO', 4), ('FOREIGN_BAR', 5),
+                      ('FOREIGN_BAZ', 6)],
+                     unittest_pb2.ForeignEnum.items())
+
+    proto = unittest_pb2.TestAllTypes()
+    self.assertEqual(['FOO', 'BAR', 'BAZ'], proto.NestedEnum.keys())
+    self.assertEqual([1, 2, 3], proto.NestedEnum.values())
+    self.assertEqual([('FOO', 1), ('BAR', 2), ('BAZ', 3)],
+                     proto.NestedEnum.items())
+
   def testRepeatedScalars(self):
     proto = unittest_pb2.TestAllTypes()
 
@@ -826,6 +945,35 @@ class ReflectionTest(unittest.TestCase):
     self.assertEqual(1, len(proto.repeated_nested_message))
     self.assertEqual(23, proto.repeated_nested_message[0].bb)
 
+  def testRepeatedCompositeRemove(self):
+    proto = unittest_pb2.TestAllTypes()
+
+    self.assertEqual(0, len(proto.repeated_nested_message))
+    m0 = proto.repeated_nested_message.add()
+    # Need to set some differentiating variable so m0 != m1 != m2:
+    m0.bb = len(proto.repeated_nested_message)
+    m1 = proto.repeated_nested_message.add()
+    m1.bb = len(proto.repeated_nested_message)
+    self.assertTrue(m0 != m1)
+    m2 = proto.repeated_nested_message.add()
+    m2.bb = len(proto.repeated_nested_message)
+    self.assertListsEqual([m0, m1, m2], proto.repeated_nested_message)
+
+    self.assertEqual(3, len(proto.repeated_nested_message))
+    proto.repeated_nested_message.remove(m0)
+    self.assertEqual(2, len(proto.repeated_nested_message))
+    self.assertEqual(m1, proto.repeated_nested_message[0])
+    self.assertEqual(m2, proto.repeated_nested_message[1])
+
+    # Removing m0 again or removing None should raise error
+    self.assertRaises(ValueError, proto.repeated_nested_message.remove, m0)
+    self.assertRaises(ValueError, proto.repeated_nested_message.remove, None)
+    self.assertEqual(2, len(proto.repeated_nested_message))
+
+    proto.repeated_nested_message.remove(m2)
+    self.assertEqual(1, len(proto.repeated_nested_message))
+    self.assertEqual(m1, proto.repeated_nested_message[0])
+
   def testHandWrittenReflection(self):
     # Hand written extensions are only supported by the pure-Python
     # implementation of the API.
@@ -856,6 +1004,68 @@ class ReflectionTest(unittest.TestCase):
     self.assertEqual(23, myproto_instance.foo_field)
     self.assertTrue(myproto_instance.HasField('foo_field'))
 
+  def testDescriptorProtoSupport(self):
+    # Hand written descriptors/reflection are only supported by the pure-Python
+    # implementation of the API.
+    if api_implementation.Type() != 'python':
+      return
+
+    def AddDescriptorField(proto, field_name, field_type):
+      AddDescriptorField.field_index += 1
+      new_field = proto.field.add()
+      new_field.name = field_name
+      new_field.type = field_type
+      new_field.number = AddDescriptorField.field_index
+      new_field.label = descriptor_pb2.FieldDescriptorProto.LABEL_OPTIONAL
+
+    AddDescriptorField.field_index = 0
+
+    desc_proto = descriptor_pb2.DescriptorProto()
+    desc_proto.name = 'Car'
+    fdp = descriptor_pb2.FieldDescriptorProto
+    AddDescriptorField(desc_proto, 'name', fdp.TYPE_STRING)
+    AddDescriptorField(desc_proto, 'year', fdp.TYPE_INT64)
+    AddDescriptorField(desc_proto, 'automatic', fdp.TYPE_BOOL)
+    AddDescriptorField(desc_proto, 'price', fdp.TYPE_DOUBLE)
+    # Add a repeated field
+    AddDescriptorField.field_index += 1
+    new_field = desc_proto.field.add()
+    new_field.name = 'owners'
+    new_field.type = fdp.TYPE_STRING
+    new_field.number = AddDescriptorField.field_index
+    new_field.label = descriptor_pb2.FieldDescriptorProto.LABEL_REPEATED
+
+    desc = descriptor.MakeDescriptor(desc_proto)
+    self.assertTrue(desc.fields_by_name.has_key('name'))
+    self.assertTrue(desc.fields_by_name.has_key('year'))
+    self.assertTrue(desc.fields_by_name.has_key('automatic'))
+    self.assertTrue(desc.fields_by_name.has_key('price'))
+    self.assertTrue(desc.fields_by_name.has_key('owners'))
+
+    class CarMessage(message.Message):
+      __metaclass__ = reflection.GeneratedProtocolMessageType
+      DESCRIPTOR = desc
+
+    prius = CarMessage()
+    prius.name = 'prius'
+    prius.year = 2010
+    prius.automatic = True
+    prius.price = 25134.75
+    prius.owners.extend(['bob', 'susan'])
+
+    serialized_prius = prius.SerializeToString()
+    new_prius = reflection.ParseMessage(desc, serialized_prius)
+    self.assertTrue(new_prius is not prius)
+    self.assertEqual(prius, new_prius)
+
+    # these are unnecessary assuming message equality works as advertised but
+    # explicitly check to be safe since we're mucking about in metaclass foo
+    self.assertEqual(prius.name, new_prius.name)
+    self.assertEqual(prius.year, new_prius.year)
+    self.assertEqual(prius.automatic, new_prius.automatic)
+    self.assertEqual(prius.price, new_prius.price)
+    self.assertEqual(prius.owners, new_prius.owners)
+
   def testTopLevelExtensionsForOptionalScalar(self):
     extendee_proto = unittest_pb2.TestAllExtensions()
     extension = unittest_pb2.optional_int32_extension
@@ -1243,7 +1453,12 @@ class ReflectionTest(unittest.TestCase):
 
   def testClear(self):
     proto = unittest_pb2.TestAllTypes()
-    test_util.SetAllFields(proto)
+    # C++ implementation does not support lazy fields right now so leave it
+    # out for now.
+    if api_implementation.Type() == 'python':
+      test_util.SetAllFields(proto)
+    else:
+      test_util.SetAllNonLazyFields(proto)
     # Clear the message.
     proto.Clear()
     self.assertEquals(proto.ByteSize(), 0)
@@ -1259,6 +1474,33 @@ class ReflectionTest(unittest.TestCase):
     empty_proto = unittest_pb2.TestAllExtensions()
     self.assertEquals(proto, empty_proto)
 
+  def testDisconnectingBeforeClear(self):
+    proto = unittest_pb2.TestAllTypes()
+    nested = proto.optional_nested_message
+    proto.Clear()
+    self.assertTrue(nested is not proto.optional_nested_message)
+    nested.bb = 23
+    self.assertTrue(not proto.HasField('optional_nested_message'))
+    self.assertEqual(0, proto.optional_nested_message.bb)
+
+    proto = unittest_pb2.TestAllTypes()
+    nested = proto.optional_nested_message
+    nested.bb = 5
+    foreign = proto.optional_foreign_message
+    foreign.c = 6
+
+    proto.Clear()
+    self.assertTrue(nested is not proto.optional_nested_message)
+    self.assertTrue(foreign is not proto.optional_foreign_message)
+    self.assertEqual(5, nested.bb)
+    self.assertEqual(6, foreign.c)
+    nested.bb = 15
+    foreign.c = 16
+    self.assertTrue(not proto.HasField('optional_nested_message'))
+    self.assertEqual(0, proto.optional_nested_message.bb)
+    self.assertTrue(not proto.HasField('optional_foreign_message'))
+    self.assertEqual(0, proto.optional_foreign_message.c)
+
   def assertInitialized(self, proto):
     self.assertTrue(proto.IsInitialized())
     # Neither method should raise an exception.
@@ -1408,7 +1650,7 @@ class ReflectionTest(unittest.TestCase):
     unicode_decode_failed = False
     try:
       message2.MergeFromString(bytes)
-    except UnicodeDecodeError, e:
+    except UnicodeDecodeError as e:
       unicode_decode_failed = True
     string_field = message2.str
     self.assertTrue(unicode_decode_failed or type(string_field) == str)
@@ -2119,7 +2361,7 @@ class SerializationTest(unittest.TestCase):
     """This method checks if the excpetion type and message are as expected."""
     try:
       callable_obj()
-    except exc_class, ex:
+    except exc_class as ex:
       # Check if the exception message is the right one.
       self.assertEqual(exception, str(ex))
       return
@@ -2131,15 +2373,22 @@ class SerializationTest(unittest.TestCase):
     self._CheckRaises(
         message.EncodeError,
         proto.SerializeToString,
-        'Message is missing required fields: a,b,c')
+        'Message protobuf_unittest.TestRequired is missing required fields: '
+        'a,b,c')
     # Shouldn't raise exceptions.
     partial = proto.SerializePartialToString()
 
+    proto2 = unittest_pb2.TestRequired()
+    self.assertFalse(proto2.HasField('a'))
+    # proto2 ParseFromString does not check that required fields are set.
+    proto2.ParseFromString(partial)
+    self.assertFalse(proto2.HasField('a'))
+
     proto.a = 1
     self._CheckRaises(
         message.EncodeError,
         proto.SerializeToString,
-        'Message is missing required fields: b,c')
+        'Message protobuf_unittest.TestRequired is missing required fields: b,c')
     # Shouldn't raise exceptions.
     partial = proto.SerializePartialToString()
 
@@ -2147,7 +2396,7 @@ class SerializationTest(unittest.TestCase):
     self._CheckRaises(
         message.EncodeError,
         proto.SerializeToString,
-        'Message is missing required fields: c')
+        'Message protobuf_unittest.TestRequired is missing required fields: c')
     # Shouldn't raise exceptions.
     partial = proto.SerializePartialToString()
 
@@ -2176,7 +2425,8 @@ class SerializationTest(unittest.TestCase):
     self._CheckRaises(
         message.EncodeError,
         proto.SerializeToString,
-        'Message is missing required fields: '
+        'Message protobuf_unittest.TestRequiredForeign '
+        'is missing required fields: '
         'optional_message.b,optional_message.c')
 
     proto.optional_message.b = 2
@@ -2188,7 +2438,7 @@ class SerializationTest(unittest.TestCase):
     self._CheckRaises(
         message.EncodeError,
         proto.SerializeToString,
-        'Message is missing required fields: '
+        'Message protobuf_unittest.TestRequiredForeign is missing required fields: '
         'repeated_message[0].b,repeated_message[0].c,'
         'repeated_message[1].a,repeated_message[1].c')
 
diff --git a/python/google/protobuf/internal/test_bad_identifiers.proto b/python/google/protobuf/internal/test_bad_identifiers.proto
new file mode 100644
index 00000000..6a82299a
--- /dev/null
+++ b/python/google/protobuf/internal/test_bad_identifiers.proto
@@ -0,0 +1,52 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: kenton@google.com (Kenton Varda)
+
+
+package protobuf_unittest;
+
+option py_generic_services = true;
+
+message TestBadIdentifiers {
+  extensions 100 to max;
+}
+
+// Make sure these reasonable extension names don't conflict with internal
+// variables.
+extend TestBadIdentifiers {
+  optional string message = 100 [default="foo"];
+  optional string descriptor = 101 [default="bar"];
+  optional string reflection = 102 [default="baz"];
+  optional string service = 103 [default="qux"];
+}
+
+message AnotherMessage {}
+service AnotherService {}
diff --git a/python/google/protobuf/internal/test_util.py b/python/google/protobuf/internal/test_util.py
index 1df16194..be8ae7be 100755
--- a/python/google/protobuf/internal/test_util.py
+++ b/python/google/protobuf/internal/test_util.py
@@ -42,8 +42,8 @@ from google.protobuf import unittest_import_pb2
 from google.protobuf import unittest_pb2
 
 
-def SetAllFields(message):
-  """Sets every field in the message to a unique value.
+def SetAllNonLazyFields(message):
+  """Sets every non-lazy field in the message to a unique value.
 
   Args:
     message: A unittest_pb2.TestAllTypes instance.
@@ -79,6 +79,7 @@ def SetAllFields(message):
   message.optional_nested_message.bb = 118
   message.optional_foreign_message.c = 119
   message.optional_import_message.d = 120
+  message.optional_public_import_message.e = 126
 
   message.optional_nested_enum = unittest_pb2.TestAllTypes.BAZ
   message.optional_foreign_enum = unittest_pb2.FOREIGN_BAZ
@@ -111,6 +112,7 @@ def SetAllFields(message):
   message.repeated_nested_message.add().bb = 218
   message.repeated_foreign_message.add().c = 219
   message.repeated_import_message.add().d = 220
+  message.repeated_lazy_message.add().bb = 227
 
   message.repeated_nested_enum.append(unittest_pb2.TestAllTypes.BAR)
   message.repeated_foreign_enum.append(unittest_pb2.FOREIGN_BAR)
@@ -140,6 +142,7 @@ def SetAllFields(message):
   message.repeated_nested_message.add().bb = 318
   message.repeated_foreign_message.add().c = 319
   message.repeated_import_message.add().d = 320
+  message.repeated_lazy_message.add().bb = 327
 
   message.repeated_nested_enum.append(unittest_pb2.TestAllTypes.BAZ)
   message.repeated_foreign_enum.append(unittest_pb2.FOREIGN_BAZ)
@@ -176,6 +179,11 @@ def SetAllFields(message):
   message.default_cord = '425'
 
 
+def SetAllFields(message):
+  SetAllNonLazyFields(message)
+  message.optional_lazy_message.bb = 127
+
+
 def SetAllExtensions(message):
   """Sets every extension in the message to a unique value.
 
@@ -211,6 +219,8 @@ def SetAllExtensions(message):
   extensions[pb2.optional_nested_message_extension].bb = 118
   extensions[pb2.optional_foreign_message_extension].c = 119
   extensions[pb2.optional_import_message_extension].d = 120
+  extensions[pb2.optional_public_import_message_extension].e = 126
+  extensions[pb2.optional_lazy_message_extension].bb = 127
 
   extensions[pb2.optional_nested_enum_extension] = pb2.TestAllTypes.BAZ
   extensions[pb2.optional_nested_enum_extension] = pb2.TestAllTypes.BAZ
@@ -244,6 +254,7 @@ def SetAllExtensions(message):
   extensions[pb2.repeated_nested_message_extension].add().bb = 218
   extensions[pb2.repeated_foreign_message_extension].add().c = 219
   extensions[pb2.repeated_import_message_extension].add().d = 220
+  extensions[pb2.repeated_lazy_message_extension].add().bb = 227
 
   extensions[pb2.repeated_nested_enum_extension].append(pb2.TestAllTypes.BAR)
   extensions[pb2.repeated_foreign_enum_extension].append(pb2.FOREIGN_BAR)
@@ -273,6 +284,7 @@ def SetAllExtensions(message):
   extensions[pb2.repeated_nested_message_extension].add().bb = 318
   extensions[pb2.repeated_foreign_message_extension].add().c = 319
   extensions[pb2.repeated_import_message_extension].add().d = 320
+  extensions[pb2.repeated_lazy_message_extension].add().bb = 327
 
   extensions[pb2.repeated_nested_enum_extension].append(pb2.TestAllTypes.BAZ)
   extensions[pb2.repeated_foreign_enum_extension].append(pb2.FOREIGN_BAZ)
@@ -407,6 +419,8 @@ def ExpectAllFieldsSet(test_case, message):
   test_case.assertEqual(118, message.optional_nested_message.bb)
   test_case.assertEqual(119, message.optional_foreign_message.c)
   test_case.assertEqual(120, message.optional_import_message.d)
+  test_case.assertEqual(126, message.optional_public_import_message.e)
+  test_case.assertEqual(127, message.optional_lazy_message.bb)
 
   test_case.assertEqual(unittest_pb2.TestAllTypes.BAZ,
                         message.optional_nested_enum)
@@ -464,6 +478,7 @@ def ExpectAllFieldsSet(test_case, message):
   test_case.assertEqual(218, message.repeated_nested_message[0].bb)
   test_case.assertEqual(219, message.repeated_foreign_message[0].c)
   test_case.assertEqual(220, message.repeated_import_message[0].d)
+  test_case.assertEqual(227, message.repeated_lazy_message[0].bb)
 
   test_case.assertEqual(unittest_pb2.TestAllTypes.BAR,
                         message.repeated_nested_enum[0])
@@ -492,6 +507,7 @@ def ExpectAllFieldsSet(test_case, message):
   test_case.assertEqual(318, message.repeated_nested_message[1].bb)
   test_case.assertEqual(319, message.repeated_foreign_message[1].c)
   test_case.assertEqual(320, message.repeated_import_message[1].d)
+  test_case.assertEqual(327, message.repeated_lazy_message[1].bb)
 
   test_case.assertEqual(unittest_pb2.TestAllTypes.BAZ,
                         message.repeated_nested_enum[1])
diff --git a/python/google/protobuf/internal/text_format_test.py b/python/google/protobuf/internal/text_format_test.py
index 73d97d18..23b50eb5 100755
--- a/python/google/protobuf/internal/text_format_test.py
+++ b/python/google/protobuf/internal/text_format_test.py
@@ -94,6 +94,28 @@ class TextFormatTest(unittest.TestCase):
       '  }\n'
       '}\n')
 
+  def testPrintBadEnumValue(self):
+    message = unittest_pb2.TestAllTypes()
+    message.optional_nested_enum = 100
+    message.optional_foreign_enum = 101
+    message.optional_import_enum = 102
+    self.CompareToGoldenText(
+        text_format.MessageToString(message),
+        'optional_nested_enum: 100\n'
+        'optional_foreign_enum: 101\n'
+        'optional_import_enum: 102\n')
+
+  def testPrintBadEnumValueExtensions(self):
+    message = unittest_pb2.TestAllExtensions()
+    message.Extensions[unittest_pb2.optional_nested_enum_extension] = 100
+    message.Extensions[unittest_pb2.optional_foreign_enum_extension] = 101
+    message.Extensions[unittest_pb2.optional_import_enum_extension] = 102
+    self.CompareToGoldenText(
+        text_format.MessageToString(message),
+        '[protobuf_unittest.optional_nested_enum_extension]: 100\n'
+        '[protobuf_unittest.optional_foreign_enum_extension]: 101\n'
+        '[protobuf_unittest.optional_import_enum_extension]: 102\n')
+
   def testPrintExotic(self):
     message = unittest_pb2.TestAllTypes()
     message.repeated_int64.append(-9223372036854775808)
@@ -399,6 +421,14 @@ class TextFormatTest(unittest.TestCase):
          'has no value with number 100.'),
         text_format.Merge, text, message)
 
+  def testMergeBadIntValue(self):
+    message = unittest_pb2.TestAllTypes()
+    text = 'optional_int32: bork'
+    self.assertRaisesWithMessage(
+        text_format.ParseError,
+        ('1:17 : Couldn\'t parse integer: bork'),
+        text_format.Merge, text, message)
+
   def assertRaisesWithMessage(self, e_class, e, func, *args, **kwargs):
     """Same as assertRaises, but also compares the exception message."""
     if hasattr(e_class, '__name__'):
@@ -408,7 +438,7 @@ class TextFormatTest(unittest.TestCase):
 
     try:
       func(*args, **kwargs)
-    except e_class, expr:
+    except e_class as expr:
       if str(expr) != e:
         msg = '%s raised, but with wrong message: "%s" instead of "%s"'
         raise self.failureException(msg % (exc_name,
@@ -427,7 +457,7 @@ class TokenizerTest(unittest.TestCase):
             'identifiER_4 : 1.1e+2 ID5:-0.23 ID6:\'aaaa\\\'bbbb\'\n'
             'ID7 : "aa\\"bb"\n\n\n\n ID8: {A:inf B:-inf C:true D:false}\n'
             'ID9: 22 ID10: -111111111111111111 ID11: -22\n'
-            'ID12: 2222222222222222222 '
+            'ID12: 2222222222222222222 ID13: 1.23456f ID14: 1.2e+2f '
             'false_bool:  0 true_BOOL:t \n true_bool1:  1 false_BOOL1:f ' )
     tokenizer = text_format._Tokenizer(text)
     methods = [(tokenizer.ConsumeIdentifier, 'identifier1'),
@@ -456,10 +486,10 @@ class TokenizerTest(unittest.TestCase):
                '{',
                (tokenizer.ConsumeIdentifier, 'A'),
                ':',
-               (tokenizer.ConsumeFloat, text_format._INFINITY),
+               (tokenizer.ConsumeFloat, float('inf')),
                (tokenizer.ConsumeIdentifier, 'B'),
                ':',
-               (tokenizer.ConsumeFloat, -text_format._INFINITY),
+               (tokenizer.ConsumeFloat, -float('inf')),
                (tokenizer.ConsumeIdentifier, 'C'),
                ':',
                (tokenizer.ConsumeBool, True),
@@ -479,6 +509,12 @@ class TokenizerTest(unittest.TestCase):
                (tokenizer.ConsumeIdentifier, 'ID12'),
                ':',
                (tokenizer.ConsumeUint64, 2222222222222222222),
+               (tokenizer.ConsumeIdentifier, 'ID13'),
+               ':',
+               (tokenizer.ConsumeFloat, 1.23456),
+               (tokenizer.ConsumeIdentifier, 'ID14'),
+               ':',
+               (tokenizer.ConsumeFloat, 1.2e+2),
                (tokenizer.ConsumeIdentifier, 'false_bool'),
                ':',
                (tokenizer.ConsumeBool, False),
@@ -556,16 +592,6 @@ class TokenizerTest(unittest.TestCase):
     tokenizer = text_format._Tokenizer(text)
     self.assertRaises(text_format.ParseError, tokenizer.ConsumeBool)
 
-  def testInfNan(self):
-    # Make sure our infinity and NaN definitions are sound.
-    self.assertEquals(float, type(text_format._INFINITY))
-    self.assertEquals(float, type(text_format._NAN))
-    self.assertTrue(text_format._NAN != text_format._NAN)
-
-    inf_times_zero = text_format._INFINITY * 0
-    self.assertTrue(inf_times_zero != inf_times_zero)
-    self.assertTrue(text_format._INFINITY > 0)
-
 
 if __name__ == '__main__':
   unittest.main()
diff --git a/python/google/protobuf/internal/unknown_fields_test.py b/python/google/protobuf/internal/unknown_fields_test.py
new file mode 100755
index 00000000..84984b40
--- /dev/null
+++ b/python/google/protobuf/internal/unknown_fields_test.py
@@ -0,0 +1,170 @@
+#! /usr/bin/python
+# -*- coding: utf-8 -*-
+#
+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Test for preservation of unknown fields in the pure Python implementation."""
+
+__author__ = 'bohdank@google.com (Bohdan Koval)'
+
+import unittest
+from google.protobuf import unittest_mset_pb2
+from google.protobuf import unittest_pb2
+from google.protobuf.internal import encoder
+from google.protobuf.internal import test_util
+from google.protobuf.internal import type_checkers
+
+
+class UnknownFieldsTest(unittest.TestCase):
+
+  def setUp(self):
+    self.descriptor = unittest_pb2.TestAllTypes.DESCRIPTOR
+    self.all_fields = unittest_pb2.TestAllTypes()
+    test_util.SetAllFields(self.all_fields)
+    self.all_fields_data = self.all_fields.SerializeToString()
+    self.empty_message = unittest_pb2.TestEmptyMessage()
+    self.empty_message.ParseFromString(self.all_fields_data)
+    self.unknown_fields = self.empty_message._unknown_fields
+
+  def GetField(self, name):
+    field_descriptor = self.descriptor.fields_by_name[name]
+    wire_type = type_checkers.FIELD_TYPE_TO_WIRE_TYPE[field_descriptor.type]
+    field_tag = encoder.TagBytes(field_descriptor.number, wire_type)
+    for tag_bytes, value in self.unknown_fields:
+      if tag_bytes == field_tag:
+        decoder = unittest_pb2.TestAllTypes._decoders_by_tag[tag_bytes]
+        result_dict = {}
+        decoder(value, 0, len(value), self.all_fields, result_dict)
+        return result_dict[field_descriptor]
+
+  def testVarint(self):
+    value = self.GetField('optional_int32')
+    self.assertEqual(self.all_fields.optional_int32, value)
+
+  def testFixed32(self):
+    value = self.GetField('optional_fixed32')
+    self.assertEqual(self.all_fields.optional_fixed32, value)
+
+  def testFixed64(self):
+    value = self.GetField('optional_fixed64')
+    self.assertEqual(self.all_fields.optional_fixed64, value)
+
+  def testLengthDelimited(self):
+    value = self.GetField('optional_string')
+    self.assertEqual(self.all_fields.optional_string, value)
+
+  def testGroup(self):
+    value = self.GetField('optionalgroup')
+    self.assertEqual(self.all_fields.optionalgroup, value)
+
+  def testSerialize(self):
+    data = self.empty_message.SerializeToString()
+
+    # Don't use assertEqual because we don't want to dump raw binary data to
+    # stdout.
+    self.assertTrue(data == self.all_fields_data)
+
+  def testCopyFrom(self):
+    message = unittest_pb2.TestEmptyMessage()
+    message.CopyFrom(self.empty_message)
+    self.assertEqual(self.unknown_fields, message._unknown_fields)
+
+  def testMergeFrom(self):
+    message = unittest_pb2.TestAllTypes()
+    message.optional_int32 = 1
+    message.optional_uint32 = 2
+    source = unittest_pb2.TestEmptyMessage()
+    source.ParseFromString(message.SerializeToString())
+
+    message.ClearField('optional_int32')
+    message.optional_int64 = 3
+    message.optional_uint32 = 4
+    destination = unittest_pb2.TestEmptyMessage()
+    destination.ParseFromString(message.SerializeToString())
+    unknown_fields = destination._unknown_fields[:]
+
+    destination.MergeFrom(source)
+    self.assertEqual(unknown_fields + source._unknown_fields,
+                     destination._unknown_fields)
+
+  def testClear(self):
+    self.empty_message.Clear()
+    self.assertEqual(0, len(self.empty_message._unknown_fields))
+
+  def testByteSize(self):
+    self.assertEqual(self.all_fields.ByteSize(), self.empty_message.ByteSize())
+
+  def testUnknownExtensions(self):
+    message = unittest_pb2.TestEmptyMessageWithExtensions()
+    message.ParseFromString(self.all_fields_data)
+    self.assertEqual(self.empty_message._unknown_fields,
+                     message._unknown_fields)
+
+  def testListFields(self):
+    # Make sure ListFields doesn't return unknown fields.
+    self.assertEqual(0, len(self.empty_message.ListFields()))
+
+  def testSerializeMessageSetWireFormatUnknownExtension(self):
+    # Create a message using the message set wire format with an unknown
+    # message.
+    raw = unittest_mset_pb2.RawMessageSet()
+
+    # Add an unknown extension.
+    item = raw.item.add()
+    item.type_id = 1545009
+    message1 = unittest_mset_pb2.TestMessageSetExtension1()
+    message1.i = 12345
+    item.message = message1.SerializeToString()
+
+    serialized = raw.SerializeToString()
+
+    # Parse message using the message set wire format.
+    proto = unittest_mset_pb2.TestMessageSet()
+    proto.MergeFromString(serialized)
+
+    # Verify that the unknown extension is serialized unchanged
+    reserialized = proto.SerializeToString()
+    new_raw = unittest_mset_pb2.RawMessageSet()
+    new_raw.MergeFromString(reserialized)
+    self.assertEqual(raw, new_raw)
+
+  def testEquals(self):
+    message = unittest_pb2.TestEmptyMessage()
+    message.ParseFromString(self.all_fields_data)
+    self.assertEqual(self.empty_message, message)
+
+    self.all_fields.ClearField('optional_string')
+    message.ParseFromString(self.all_fields.SerializeToString())
+    self.assertNotEqual(self.empty_message, message)
+
+
+if __name__ == '__main__':
+  unittest.main()