Fix failing tests.

1. Fix C++ tests.
  * Add missing files to Makefile.am and fix distcheck in tests.sh
  * Remove BUILT_SOURCES from conformance/Makefile.am.
  * Add some missing override keyword.
  * Add a type cast to int64 because our StrCat() in stubs can't handle size_t.
2. Fix Java tests.
  * Add missing test dependency on guava in pom.xml.
  * Include newly referenced test data in test resources.
  * Manually fix map_lite_test.proto which is overwritten because it's mapped
    from map_test.proto in google3.
  * Add back "optimize_for = LITE_RUNTIME" which is still needed to keep the
    opensource test passing as it's still running lite tests.
  * Add a type cast in newBuilder() because without it the code doesn't compile
    with openjdk javac 1.8 (the compiler can't figure if it's the right type
    due to complex generic typing).
3. Fix Python tests.
  * Remove/replace references to <hash_map>.
  * Suppress more warnings in setup.py.
  * Replace incorrect header inclusion for google/protobuf/proto_api.h.
  * Add strings::EndsWith to google/protobuf/stubs/strutil.h because it's
    referenced in the updated python C extension code.
  * Replace proto2 with google::protobuf. The proto2 name is leaked to
    opensource because we removed the subsitition rule for proto2 namespace
    but only fixed C++ source code and forgot to update python C extension code.

10 files changed, 671 insertions, 22 deletions

diff --git a/python/google/protobuf/pyext/extension_dict.h b/python/google/protobuf/pyext/extension_dict.h
index d800d479..a7d6bb7b 100644
--- a/python/google/protobuf/pyext/extension_dict.h
+++ b/python/google/protobuf/pyext/extension_dict.h
@@ -37,7 +37,6 @@
 #include <Python.h>
 
 #include <memory>
-#include <hash_map>
 
 #include <google/protobuf/pyext/message.h>
 
diff --git a/python/google/protobuf/pyext/field.cc b/python/google/protobuf/pyext/field.cc
new file mode 100755
index 00000000..1afd4583
--- /dev/null
+++ b/python/google/protobuf/pyext/field.cc
@@ -0,0 +1,142 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+
+#include <google/protobuf/pyext/field.h>
+
+#include <google/protobuf/descriptor.h>
+#include <google/protobuf/pyext/descriptor.h>
+#include <google/protobuf/pyext/message.h>
+
+#if PY_MAJOR_VERSION >= 3
+  #define PyString_FromFormat PyUnicode_FromFormat
+#endif
+
+namespace google {
+namespace protobuf {
+namespace python {
+
+namespace field {
+
+static PyObject* Repr(PyMessageFieldProperty* self) {
+  return PyString_FromFormat("<field property '%s'>",
+                             self->field_descriptor->full_name().c_str());
+}
+
+static PyObject* DescrGet(PyMessageFieldProperty* self, PyObject* obj,
+                          PyObject* type) {
+  if (obj == NULL) {
+    Py_INCREF(self);
+    return reinterpret_cast<PyObject*>(self);
+  }
+  return cmessage::GetFieldValue(reinterpret_cast<CMessage*>(obj),
+                                 self->field_descriptor);
+}
+
+static int DescrSet(PyMessageFieldProperty* self, PyObject* obj,
+                    PyObject* value) {
+  if (value == NULL) {
+    PyErr_SetString(PyExc_AttributeError, "Cannot delete field attribute");
+    return -1;
+  }
+  return cmessage::SetFieldValue(reinterpret_cast<CMessage*>(obj),
+                                 self->field_descriptor, value);
+}
+
+static PyObject* GetDescriptor(PyMessageFieldProperty* self, void* closure) {
+  return PyFieldDescriptor_FromDescriptor(self->field_descriptor);
+}
+
+static PyObject* GetDoc(PyMessageFieldProperty* self, void* closure) {
+  return PyString_FromFormat("Field %s",
+                             self->field_descriptor->full_name().c_str());
+}
+
+static PyGetSetDef Getters[] = {
+    {"DESCRIPTOR", (getter)GetDescriptor, NULL, "Field descriptor"},
+    {"__doc__", (getter)GetDoc, NULL, NULL},
+    {NULL}};
+}  // namespace field
+
+static PyTypeObject _CFieldProperty_Type = {
+    PyVarObject_HEAD_INIT(&PyType_Type, 0)    // head
+    FULL_MODULE_NAME ".FieldProperty",        // tp_name
+    sizeof(PyMessageFieldProperty),           // tp_basicsize
+    0,                                        // tp_itemsize
+    0,                                        // tp_dealloc
+    0,                                        // tp_print
+    0,                                        // tp_getattr
+    0,                                        // tp_setattr
+    0,                                        // tp_compare
+    (reprfunc)field::Repr,                    // tp_repr
+    0,                                        // tp_as_number
+    0,                                        // tp_as_sequence
+    0,                                        // tp_as_mapping
+    0,                                        // tp_hash
+    0,                                        // tp_call
+    0,                                        // tp_str
+    0,                                        // tp_getattro
+    0,                                        // tp_setattro
+    0,                                        // tp_as_buffer
+    Py_TPFLAGS_DEFAULT,                       // tp_flags
+    "Field property of a Message",            // tp_doc
+    0,                                        // tp_traverse
+    0,                                        // tp_clear
+    0,                                        // tp_richcompare
+    0,                                        // tp_weaklistoffset
+    0,                                        // tp_iter
+    0,                                        // tp_iternext
+    0,                                        // tp_methods
+    0,                                        // tp_members
+    field::Getters,                           // tp_getset
+    0,                                        // tp_base
+    0,                                        // tp_dict
+    (descrgetfunc)field::DescrGet,            // tp_descr_get
+    (descrsetfunc)field::DescrSet,            // tp_descr_set
+    0,                                        // tp_dictoffset
+    0,                                        // tp_init
+    0,                                        // tp_alloc
+    0,                                        // tp_new
+};
+PyTypeObject* CFieldProperty_Type = &_CFieldProperty_Type;
+
+PyObject* NewFieldProperty(const FieldDescriptor* field_descriptor) {
+  // Create a new descriptor object
+  PyMessageFieldProperty* property =
+      PyObject_New(PyMessageFieldProperty, CFieldProperty_Type);
+  if (property == NULL) {
+    return NULL;
+  }
+  property->field_descriptor = field_descriptor;
+  return reinterpret_cast<PyObject*>(property);
+}
+
+}  // namespace python
+}  // namespace protobuf
+}  // namespace google
diff --git a/python/google/protobuf/pyext/field.h b/python/google/protobuf/pyext/field.h
new file mode 100755
index 00000000..7b4660ca
--- /dev/null
+++ b/python/google/protobuf/pyext/field.h
@@ -0,0 +1,59 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+
+#ifndef GOOGLE_PROTOBUF_PYTHON_CPP_FIELD_H__
+#define GOOGLE_PROTOBUF_PYTHON_CPP_FIELD_H__
+
+#include <Python.h>
+
+namespace google {
+namespace protobuf {
+
+class FieldDescriptor;
+
+namespace python {
+
+// A data descriptor that represents a field in a Message class.
+struct PyMessageFieldProperty {
+  PyObject_HEAD;
+
+  // This pointer is owned by the same pool as the Message class it belongs to.
+  const FieldDescriptor* field_descriptor;
+};
+
+extern PyTypeObject* CFieldProperty_Type;
+
+PyObject* NewFieldProperty(const FieldDescriptor* field_descriptor);
+
+}  // namespace python
+}  // namespace protobuf
+}  // namespace google
+
+#endif  // GOOGLE_PROTOBUF_PYTHON_CPP_FIELD_H__
diff --git a/python/google/protobuf/pyext/map_container.cc b/python/google/protobuf/pyext/map_container.cc
index 3eec49c7..cc57d1c2 100644
--- a/python/google/protobuf/pyext/map_container.cc
+++ b/python/google/protobuf/pyext/map_container.cc
@@ -75,7 +75,7 @@ class MapReflectionFriend {
 struct MapIterator {
   PyObject_HEAD;
 
-  std::unique_ptr<::proto2::MapIterator> iter;
+  std::unique_ptr<google::protobuf::MapIterator> iter;
 
   // A pointer back to the container, so we can notice changes to the version.
   // We own a ref on this.
@@ -314,7 +314,7 @@ static MapContainer* GetMap(PyObject* obj) {
 
 Py_ssize_t MapReflectionFriend::Length(PyObject* _self) {
   MapContainer* self = GetMap(_self);
-  const proto2::Message* message = self->message;
+  const Message* message = self->message;
   return message->GetReflection()->MapSize(*message,
                                            self->parent_field_descriptor);
 }
@@ -423,7 +423,7 @@ int MapContainer::Release() {
 // ScalarMap ///////////////////////////////////////////////////////////////////
 
 PyObject *NewScalarMapContainer(
-    CMessage* parent, const proto2::FieldDescriptor* parent_field_descriptor) {
+    CMessage* parent, const FieldDescriptor* parent_field_descriptor) {
   if (!CheckFieldBelongsToMessage(parent_field_descriptor, parent->message)) {
     return NULL;
   }
@@ -548,7 +548,7 @@ PyObject* MapReflectionFriend::ScalarMapToStr(PyObject* _self) {
   MapContainer* self = GetMap(_self);
   Message* message = self->GetMutableMessage();
   const Reflection* reflection = message->GetReflection();
-  for (proto2::MapIterator it = reflection->MapBegin(
+  for (google::protobuf::MapIterator it = reflection->MapBegin(
            message, self->parent_field_descriptor);
        it != reflection->MapEnd(message, self->parent_field_descriptor);
        ++it) {
@@ -704,7 +704,7 @@ static PyObject* GetCMessage(MessageMapContainer* self, Message* message,
 }
 
 PyObject* NewMessageMapContainer(
-    CMessage* parent, const proto2::FieldDescriptor* parent_field_descriptor,
+    CMessage* parent, const FieldDescriptor* parent_field_descriptor,
     CMessageClass* message_class) {
   if (!CheckFieldBelongsToMessage(parent_field_descriptor, parent->message)) {
     return NULL;
@@ -837,7 +837,7 @@ PyObject* MapReflectionFriend::MessageMapToStr(PyObject* _self) {
   MessageMapContainer* self = GetMessageMap(_self);
   Message* message = self->GetMutableMessage();
   const Reflection* reflection = message->GetReflection();
-  for (proto2::MapIterator it = reflection->MapBegin(
+  for (google::protobuf::MapIterator it = reflection->MapBegin(
            message, self->parent_field_descriptor);
        it != reflection->MapEnd(message, self->parent_field_descriptor);
        ++it) {
@@ -1011,7 +1011,7 @@ PyObject* MapReflectionFriend::GetIterator(PyObject *_self) {
     Message* message = self->GetMutableMessage();
     const Reflection* reflection = message->GetReflection();
 
-    iter->iter.reset(new ::proto2::MapIterator(
+    iter->iter.reset(new google::protobuf::MapIterator(
         reflection->MapBegin(message, self->parent_field_descriptor)));
   }
 
diff --git a/python/google/protobuf/pyext/message.cc b/python/google/protobuf/pyext/message.cc
index 5d0e37fa..e138c93d 100644
--- a/python/google/protobuf/pyext/message.cc
+++ b/python/google/protobuf/pyext/message.cc
@@ -171,7 +171,7 @@ static int AddDescriptors(PyObject* cls, const Descriptor* descriptor) {
   // <message descriptor>.extensions_by_name[name]
   // which was defined previously.
   for (int i = 0; i < descriptor->extension_count(); ++i) {
-    const proto2::FieldDescriptor* field = descriptor->extension(i);
+    const FieldDescriptor* field = descriptor->extension(i);
     ScopedPyObjectPtr extension_field(PyFieldDescriptor_FromDescriptor(field));
     if (extension_field == NULL) {
       return -1;
@@ -2344,7 +2344,7 @@ static PyObject* RichCompare(CMessage* self, PyObject* other, int opid) {
   if (!PyObject_TypeCheck(other, CMessage_Type)) {
     equals = false;
   }
-  const proto2::Message* other_message =
+  const Message* other_message =
       reinterpret_cast<CMessage*>(other)->message;
   // If messages don't have the same descriptors, they are not equal.
   if (equals &&
@@ -2352,7 +2352,7 @@ static PyObject* RichCompare(CMessage* self, PyObject* other, int opid) {
     equals = false;
   }
   // Check the message contents.
-  if (equals && !proto2::util::MessageDifferencer::Equals(
+  if (equals && !util::MessageDifferencer::Equals(
           *self->message,
           *reinterpret_cast<CMessage*>(other)->message)) {
     equals = false;
diff --git a/python/google/protobuf/pyext/message.h b/python/google/protobuf/pyext/message.h
index e729e448..cbd422be 100644
--- a/python/google/protobuf/pyext/message.h
+++ b/python/google/protobuf/pyext/message.h
@@ -38,7 +38,7 @@
 
 #include <memory>
 #include <string>
-#include <hash_map>
+#include <unordered_map>
 
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/pyext/thread_unsafe_shared_ptr.h>
@@ -105,7 +105,7 @@ typedef struct CMessage {
   // Also cache extension fields.
   // The FieldDescriptor is owned by the message's pool; PyObject references
   // are owned.
-  typedef __gnu_cxx::hash_map<const FieldDescriptor*, PyObject*>
+  typedef std::unordered_map<const FieldDescriptor*, PyObject*>
       CompositeFieldsMap;
   CompositeFieldsMap* composite_fields;
 
diff --git a/python/google/protobuf/pyext/message_module.cc b/python/google/protobuf/pyext/message_module.cc
index 29d56702..8d465eb5 100644
--- a/python/google/protobuf/pyext/message_module.cc
+++ b/python/google/protobuf/pyext/message_module.cc
@@ -31,19 +31,19 @@
 #include <Python.h>
 
 #include <google/protobuf/pyext/message.h>
-#include <google/protobuf/python/proto_api.h>
+#include <google/protobuf/proto_api.h>
 
 #include <google/protobuf/message_lite.h>
 
 namespace {
 
 // C++ API.  Clients get at this via proto_api.h
-struct ApiImplementation : proto2::python::PyProto_API {
-  const proto2::Message* GetMessagePointer(PyObject* msg) const override {
-    return proto2::python::PyMessage_GetMessagePointer(msg);
+struct ApiImplementation : google::protobuf::python::PyProto_API {
+  const google::protobuf::Message* GetMessagePointer(PyObject* msg) const override {
+    return google::protobuf::python::PyMessage_GetMessagePointer(msg);
   }
-  proto2::Message* GetMutableMessagePointer(PyObject* msg) const override {
-    return proto2::python::PyMessage_GetMutableMessagePointer(msg);
+  google::protobuf::Message* GetMutableMessagePointer(PyObject* msg) const override {
+    return google::protobuf::python::PyMessage_GetMutableMessagePointer(msg);
   }
 };
 
@@ -58,7 +58,7 @@ static const char module_docstring[] =
 
 static PyMethodDef ModuleMethods[] = {
   {"SetAllowOversizeProtos",
-    (PyCFunction)proto2::python::cmessage::SetAllowOversizeProtos,
+    (PyCFunction)google::protobuf::python::cmessage::SetAllowOversizeProtos,
     METH_O, "Enable/disable oversize proto parsing."},
   // DO NOT USE: For migration and testing only.
   { NULL, NULL}
@@ -94,7 +94,7 @@ PyMODINIT_FUNC INITFUNC() {
     return INITFUNC_ERRORVAL;
   }
 
-  if (!proto2::python::InitProto2MessageModule(m)) {
+  if (!google::protobuf::python::InitProto2MessageModule(m)) {
     Py_DECREF(m);
     return INITFUNC_ERRORVAL;
   }
@@ -102,7 +102,7 @@ PyMODINIT_FUNC INITFUNC() {
   // Adds the C++ API
   if (PyObject* api =
           PyCapsule_New(new ApiImplementation(),
-                        proto2::python::PyProtoAPICapsuleName(), NULL)) {
+                        google::protobuf::python::PyProtoAPICapsuleName(), NULL)) {
     PyModule_AddObject(m, "proto_API", api);
   } else {
     return INITFUNC_ERRORVAL;
diff --git a/python/google/protobuf/pyext/unknown_fields.cc b/python/google/protobuf/pyext/unknown_fields.cc
new file mode 100755
index 00000000..760452f2
--- /dev/null
+++ b/python/google/protobuf/pyext/unknown_fields.cc
@@ -0,0 +1,355 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+
+#include <google/protobuf/pyext/unknown_fields.h>
+
+#include <Python.h>
+#include <set>
+#include <memory>
+
+#include <google/protobuf/message.h>
+#include <google/protobuf/pyext/message.h>
+#include <google/protobuf/pyext/scoped_pyobject_ptr.h>
+#include <google/protobuf/unknown_field_set.h>
+#include <google/protobuf/wire_format_lite.h>
+
+#if PY_MAJOR_VERSION >= 3
+  #define PyInt_FromLong PyLong_FromLong
+#endif
+
+namespace google {
+namespace protobuf {
+namespace python {
+
+namespace unknown_fields {
+
+static Py_ssize_t Len(PyObject* pself) {
+  PyUnknownFields* self =
+      reinterpret_cast<PyUnknownFields*>(pself);
+  if (self->fields == NULL) {
+    PyErr_Format(PyExc_ValueError,
+                 "UnknownFields does not exist. "
+                 "The parent message might be cleared.");
+    return -1;
+  }
+  return self->fields->field_count();
+}
+
+void Clear(PyUnknownFields* self) {
+  for (std::set<PyUnknownFields*>::iterator it =
+           self->sub_unknown_fields.begin();
+       it != self->sub_unknown_fields.end(); it++) {
+    Clear(*it);
+  }
+  self->fields = NULL;
+  self->sub_unknown_fields.clear();
+}
+
+PyObject* NewPyUnknownFieldRef(PyUnknownFields* parent,
+                               Py_ssize_t index);
+
+static PyObject* Item(PyObject* pself, Py_ssize_t index) {
+  PyUnknownFields* self =
+      reinterpret_cast<PyUnknownFields*>(pself);
+  if (self->fields == NULL) {
+    PyErr_Format(PyExc_ValueError,
+                 "UnknownFields does not exist. "
+                 "The parent message might be cleared.");
+    return NULL;
+  }
+  Py_ssize_t total_size = self->fields->field_count();
+  if (index < 0) {
+    index = total_size + index;
+  }
+  if (index < 0 || index >= total_size) {
+    PyErr_Format(PyExc_IndexError,
+                 "index (%zd) out of range",
+                 index);
+    return NULL;
+  }
+
+  return unknown_fields::NewPyUnknownFieldRef(self, index);
+}
+
+PyObject* NewPyUnknownFields(CMessage* c_message) {
+  PyUnknownFields* self = reinterpret_cast<PyUnknownFields*>(
+      PyType_GenericAlloc(&PyUnknownFields_Type, 0));
+  if (self == NULL) {
+    return NULL;
+  }
+  // Call "placement new" to initialize PyUnknownFields.
+  new (self) PyUnknownFields;
+
+  Py_INCREF(c_message);
+  self->parent = reinterpret_cast<PyObject*>(c_message);
+  Message* message = c_message->message;
+  const Reflection* reflection = message->GetReflection();
+  self->fields = &reflection->GetUnknownFields(*message);
+
+  return reinterpret_cast<PyObject*>(self);
+}
+
+PyObject* NewPyUnknownFieldRef(PyUnknownFields* parent,
+                               Py_ssize_t index) {
+  PyUnknownFieldRef* self = reinterpret_cast<PyUnknownFieldRef*>(
+      PyType_GenericAlloc(&PyUnknownFieldRef_Type, 0));
+  if (self == NULL) {
+    return NULL;
+  }
+
+  Py_INCREF(parent);
+  self->parent = parent;
+  self->index = index;
+
+  return reinterpret_cast<PyObject*>(self);
+}
+
+static void Dealloc(PyObject* pself) {
+  PyUnknownFields* self =
+      reinterpret_cast<PyUnknownFields*>(pself);
+  if (PyObject_TypeCheck(self->parent, &PyUnknownFields_Type)) {
+    reinterpret_cast<PyUnknownFields*>(
+        self->parent)->sub_unknown_fields.erase(self);
+  }
+  Py_CLEAR(self->parent);
+  self->~PyUnknownFields();
+}
+
+static PySequenceMethods SqMethods = {
+  Len,        /* sq_length */
+  0,          /* sq_concat */
+  0,          /* sq_repeat */
+  Item,       /* sq_item */
+  0,          /* sq_slice */
+  0,          /* sq_ass_item */
+};
+
+}  // namespace unknown_fields
+
+PyTypeObject PyUnknownFields_Type = {
+  PyVarObject_HEAD_INIT(&PyType_Type, 0)
+  FULL_MODULE_NAME ".PyUnknownFields",  // tp_name
+  sizeof(PyUnknownFields),             // tp_basicsize
+  0,                                   //  tp_itemsize
+  unknown_fields::Dealloc,             //  tp_dealloc
+  0,                                   //  tp_print
+  0,                                   //  tp_getattr
+  0,                                   //  tp_setattr
+  0,                                   //  tp_compare
+  0,                                   //  tp_repr
+  0,                                   //  tp_as_number
+  &unknown_fields::SqMethods,          //  tp_as_sequence
+  0,                                   //  tp_as_mapping
+  PyObject_HashNotImplemented,         //  tp_hash
+  0,                                   //  tp_call
+  0,                                   //  tp_str
+  0,                                   //  tp_getattro
+  0,                                   //  tp_setattro
+  0,                                   //  tp_as_buffer
+  Py_TPFLAGS_DEFAULT,                  //  tp_flags
+  "unknown field set",                 //  tp_doc
+  0,                                   //  tp_traverse
+  0,                                   //  tp_clear
+  0,                                   //  tp_richcompare
+  0,                                   //  tp_weaklistoffset
+  0,                                   //  tp_iter
+  0,                                   //  tp_iternext
+  0,                                   //  tp_methods
+  0,                                   //  tp_members
+  0,                                   //  tp_getset
+  0,                                   //  tp_base
+  0,                                   //  tp_dict
+  0,                                   //  tp_descr_get
+  0,                                   //  tp_descr_set
+  0,                                   //  tp_dictoffset
+  0,                                   //  tp_init
+};
+
+namespace unknown_field {
+static PyObject* PyUnknownFields_FromUnknownFieldSet(
+    PyUnknownFields* parent, const UnknownFieldSet& fields) {
+  PyUnknownFields* self = reinterpret_cast<PyUnknownFields*>(
+      PyType_GenericAlloc(&PyUnknownFields_Type, 0));
+  if (self == NULL) {
+    return NULL;
+  }
+  // Call "placement new" to initialize PyUnknownFields.
+  new (self) PyUnknownFields;
+
+  Py_INCREF(parent);
+  self->parent = reinterpret_cast<PyObject*>(parent);
+  self->fields = &fields;
+  parent->sub_unknown_fields.emplace(self);
+
+  return reinterpret_cast<PyObject*>(self);
+}
+
+const UnknownField* GetUnknownField(PyUnknownFieldRef* self) {
+  const UnknownFieldSet* fields = self->parent->fields;
+  if (fields == NULL) {
+    PyErr_Format(PyExc_ValueError,
+                 "UnknownField does not exist. "
+                 "The parent message might be cleared.");
+    return NULL;
+  }
+  ssize_t total_size = fields->field_count();
+  if (self->index >= total_size) {
+    PyErr_Format(PyExc_ValueError,
+                 "UnknownField does not exist. "
+                 "The parent message might be cleared.");
+    return NULL;
+  }
+  return &fields->field(self->index);
+}
+
+static PyObject* GetFieldNumber(PyUnknownFieldRef* self, void *closure) {
+  const UnknownField* unknown_field = GetUnknownField(self);
+  if (unknown_field == NULL) {
+    return NULL;
+  }
+  return PyInt_FromLong(unknown_field->number());
+}
+
+using internal::WireFormatLite;
+static PyObject* GetWireType(PyUnknownFieldRef* self, void *closure) {
+  const UnknownField* unknown_field = GetUnknownField(self);
+  if (unknown_field == NULL) {
+    return NULL;
+  }
+
+  // Assign a default value to suppress may-unintialized warnings (errors
+  // when built in some places).
+  WireFormatLite::WireType wire_type = WireFormatLite::WIRETYPE_VARINT;
+  switch (unknown_field->type()) {
+    case UnknownField::TYPE_VARINT:
+      wire_type = WireFormatLite::WIRETYPE_VARINT;
+      break;
+    case UnknownField::TYPE_FIXED32:
+      wire_type = WireFormatLite::WIRETYPE_FIXED32;
+      break;
+    case UnknownField::TYPE_FIXED64:
+      wire_type = WireFormatLite::WIRETYPE_FIXED64;
+      break;
+    case UnknownField::TYPE_LENGTH_DELIMITED:
+      wire_type = WireFormatLite::WIRETYPE_LENGTH_DELIMITED;
+      break;
+    case UnknownField::TYPE_GROUP:
+      wire_type = WireFormatLite::WIRETYPE_START_GROUP;
+      break;
+  }
+  return PyInt_FromLong(wire_type);
+}
+
+static PyObject* GetData(PyUnknownFieldRef* self, void *closure) {
+  const UnknownField* field = GetUnknownField(self);
+  if (field == NULL) {
+    return NULL;
+  }
+  PyObject* data = NULL;
+  switch (field->type()) {
+    case UnknownField::TYPE_VARINT:
+      data = PyInt_FromLong(field->varint());
+      break;
+    case UnknownField::TYPE_FIXED32:
+      data = PyInt_FromLong(field->fixed32());
+      break;
+    case UnknownField::TYPE_FIXED64:
+      data = PyInt_FromLong(field->fixed64());
+      break;
+    case UnknownField::TYPE_LENGTH_DELIMITED:
+      data = PyBytes_FromStringAndSize(field->length_delimited().data(),
+                                       field->GetLengthDelimitedSize());
+      break;
+    case UnknownField::TYPE_GROUP:
+      data = PyUnknownFields_FromUnknownFieldSet(
+          self->parent, field->group());
+      break;
+  }
+  return data;
+}
+
+static void Dealloc(PyObject* pself) {
+  PyUnknownFieldRef* self =
+      reinterpret_cast<PyUnknownFieldRef*>(pself);
+  Py_CLEAR(self->parent);
+}
+
+static PyGetSetDef Getters[] = {
+  {"field_number", (getter)GetFieldNumber, NULL},
+  {"wire_type", (getter)GetWireType, NULL},
+  {"data", (getter)GetData, NULL},
+  {NULL}
+};
+
+}  // namespace unknown_field
+
+PyTypeObject PyUnknownFieldRef_Type = {
+  PyVarObject_HEAD_INIT(&PyType_Type, 0)
+  FULL_MODULE_NAME ".PyUnknownFieldRef",  // tp_name
+  sizeof(PyUnknownFieldRef),           //  tp_basicsize
+  0,                                   //  tp_itemsize
+  unknown_field::Dealloc,              //  tp_dealloc
+  0,                                   //  tp_print
+  0,                                   //  tp_getattr
+  0,                                   //  tp_setattr
+  0,                                   //  tp_compare
+  0,                                   //  tp_repr
+  0,                                   //  tp_as_number
+  0,                                   //  tp_as_sequence
+  0,                                   //  tp_as_mapping
+  PyObject_HashNotImplemented,         //  tp_hash
+  0,                                   //  tp_call
+  0,                                   //  tp_str
+  0,                                   //  tp_getattro
+  0,                                   //  tp_setattro
+  0,                                   //  tp_as_buffer
+  Py_TPFLAGS_DEFAULT,                  //  tp_flags
+  "unknown field",                     //  tp_doc
+  0,                                   //  tp_traverse
+  0,                                   //  tp_clear
+  0,                                   //  tp_richcompare
+  0,                                   //  tp_weaklistoffset
+  0,                                   //  tp_iter
+  0,                                   //  tp_iternext
+  0,                                   //  tp_methods
+  0,                                   //  tp_members
+  unknown_field::Getters,              //  tp_getset
+  0,                                   //  tp_base
+  0,                                   //  tp_dict
+  0,                                   //  tp_descr_get
+  0,                                   //  tp_descr_set
+  0,                                   //  tp_dictoffset
+  0,                                   //  tp_init
+};
+
+
+}  // namespace python
+}  // namespace protobuf
+}  // namespace google
diff --git a/python/google/protobuf/pyext/unknown_fields.h b/python/google/protobuf/pyext/unknown_fields.h
new file mode 100755
index 00000000..94d55e14
--- /dev/null
+++ b/python/google/protobuf/pyext/unknown_fields.h
@@ -0,0 +1,90 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+
+#ifndef GOOGLE_PROTOBUF_PYTHON_CPP_UNKNOWN_FIELDS_H__
+#define GOOGLE_PROTOBUF_PYTHON_CPP_UNKNOWN_FIELDS_H__
+
+#include <Python.h>
+
+#include <memory>
+#include <set>
+
+#include <google/protobuf/pyext/message.h>
+
+namespace google {
+namespace protobuf {
+
+class UnknownField;
+class UnknownFieldSet;
+
+namespace python {
+struct CMessage;
+
+typedef struct PyUnknownFields {
+  PyObject_HEAD;
+  // Strong pointer to the parent CMessage or PyUnknownFields.
+  // The top PyUnknownFields holds a reference to its parent CMessage
+  // object before release.
+  // Sub PyUnknownFields holds reference to parent PyUnknownFields.
+  PyObject* parent;
+
+  // Pointer to the C++ UnknownFieldSet.
+  // PyUnknownFields does not own this pointer.
+  const UnknownFieldSet* fields;
+
+  // Weak references to child unknown fields.
+  std::set<PyUnknownFields*> sub_unknown_fields;
+} PyUnknownFields;
+
+typedef struct PyUnknownFieldRef {
+  PyObject_HEAD;
+  // Every Python PyUnknownFieldRef holds a reference to its parent
+  // PyUnknownFields in order to keep it alive.
+  PyUnknownFields* parent;
+
+  // The UnknownField index in UnknownFields.
+  Py_ssize_t index;
+} UknownFieldRef;
+
+extern PyTypeObject PyUnknownFields_Type;
+extern PyTypeObject PyUnknownFieldRef_Type;
+
+namespace unknown_fields {
+
+// Builds an PyUnknownFields for a specific message.
+PyObject* NewPyUnknownFields(CMessage *parent);
+void Clear(PyUnknownFields* self);
+
+}  // namespace unknown_fields
+}  // namespace python
+}  // namespace protobuf
+}  // namespace google
+
+#endif  // GOOGLE_PROTOBUF_PYTHON_CPP_UNKNOWN_FIELDS_H__
diff --git a/python/setup.py b/python/setup.py
index 5ec4dcbd..63c2d0e0 100755
--- a/python/setup.py
+++ b/python/setup.py
@@ -185,8 +185,12 @@ if __name__ == '__main__':
         extra_compile_args.append('-Wno-write-strings')
         extra_compile_args.append('-Wno-invalid-offsetof')
         extra_compile_args.append('-Wno-sign-compare')
+        extra_compile_args.append('-Wno-unused-variable')
         extra_compile_args.append('-std=c++11')
 
+    if sys.platform == 'darwin':
+      extra_compile_args.append("-Wno-shorten-64-to-32");
+
     # https://github.com/Theano/Theano/issues/4926
     if sys.platform == 'win32':
       extra_compile_args.append('-D_hypot=hypot')