Internal change

PiperOrigin-RevId: 485680539

python/google/protobuf/descriptor.py

@@ -641,6 +641,24 @@ class FieldDescriptor(DescriptorBase):
         'has_presence is not ready to use because field %s is not'
         ' linked with message type nor file' % self.full_name)
 
+  @property
+  def is_packed(self):
+    """Returns if the field is packed."""
+    if self.label != FieldDescriptor.LABEL_REPEATED:
+      return False
+    field_type = self.type
+    if (field_type == FieldDescriptor.TYPE_STRING or
+        field_type == FieldDescriptor.TYPE_GROUP or
+        field_type == FieldDescriptor.TYPE_MESSAGE or
+        field_type == FieldDescriptor.TYPE_BYTES):
+      return False
+    if self.containing_type.syntax == 'proto2':
+      return self.has_options and self.GetOptions().packed
+    else:
+      return (not self.has_options or
+              not self.GetOptions().HasField('packed') or
+              self.GetOptions().packed)
+
   @staticmethod
   def ProtoTypeToCppProtoType(proto_type):
     """Converts from a Python proto type to a C++ Proto Type.

python/google/protobuf/internal/python_message.py

@@ -283,20 +283,9 @@ def _IsMessageMapField(field):
 
 def _AttachFieldHelpers(cls, field_descriptor):
   is_repeated = (field_descriptor.label == _FieldDescriptor.LABEL_REPEATED)
-  is_packable = (is_repeated and
-                 wire_format.IsTypePackable(field_descriptor.type))
   is_proto3 = field_descriptor.containing_type.syntax == 'proto3'
-  if not is_packable:
-    is_packed = False
-  elif field_descriptor.containing_type.syntax == 'proto2':
-    is_packed = (field_descriptor.has_options and
-                field_descriptor.GetOptions().packed)
-  else:
-    has_packed_false = (field_descriptor.has_options and
-                        field_descriptor.GetOptions().HasField('packed') and
-                        field_descriptor.GetOptions().packed == False)
-    is_packed = not has_packed_false
   is_map_entry = _IsMapField(field_descriptor)
+  is_packed = field_descriptor.is_packed
 
   if is_map_entry:
     field_encoder = encoder.MapEncoder(field_descriptor)