Add reference leak check to Python timestamp_test and duration_test. Fix a refleak bug when assign datetime/duration to Timestamp/Duration

PiperOrigin-RevId: 758812845

Author: anandolee

python/google/protobuf/internal/duration_test.py

@@ -12,11 +12,13 @@
 import unittest
 
 from google.protobuf import duration
+from google.protobuf.internal import testing_refleaks
 from google.protobuf.internal import well_known_types_test_pb2
 
 from google.protobuf import duration_pb2
 
 
+@testing_refleaks.TestCase
 class DurationTest(unittest.TestCase):
 
   def test_duration_integer_conversion(self):

python/google/protobuf/internal/timestamp_test.py

@@ -12,11 +12,13 @@
 import unittest
 
 from google.protobuf import timestamp
+from google.protobuf.internal import testing_refleaks
 from google.protobuf.internal import well_known_types_test_pb2
 
 from google.protobuf import timestamp_pb2
 
 
+@testing_refleaks.TestCase
 class TimestampTest(unittest.TestCase):
 
   def test_timestamp_integer_conversion(self):

python/google/protobuf/pyext/message.cc

@@ -2641,11 +2641,11 @@ int SetFieldValue(CMessage* self, const FieldDescriptor* field_descriptor,
   } else if (field_descriptor->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
     if (field_descriptor->message_type()->well_known_type() !=
         Descriptor::WELLKNOWNTYPE_UNSPECIFIED) {
-      PyObject* sub_message = GetFieldValue(self, field_descriptor);
-      if (PyObject_HasAttrString(sub_message, "_internal_assign")) {
+      ScopedPyObjectPtr sub_message(GetFieldValue(self, field_descriptor));
+      if (PyObject_HasAttrString(sub_message.get(), "_internal_assign")) {
         AssureWritable(self);
-        ScopedPyObjectPtr ok(
-            PyObject_CallMethod(sub_message, "_internal_assign", "O", value));
+        ScopedPyObjectPtr ok(PyObject_CallMethod(
+            sub_message.get(), "_internal_assign", "O", value));
         if (ok.get() == nullptr) {
           return -1;
         }

python/message.c

@@ -992,10 +992,12 @@ int PyUpb_Message_SetFieldValue(PyObject* _self, const upb_FieldDef* field,
       if (PyObject_HasAttrString(sub_message, "_internal_assign")) {
         PyObject* ok =
             PyObject_CallMethod(sub_message, "_internal_assign", "O", value);
+        Py_DECREF(sub_message);
         if (!ok) return -1;
         Py_DECREF(ok);
         return 0;
       }
+      Py_DECREF(sub_message);
     }
     PyErr_Format(exc,
                  "Assignment not allowed to message "