Soft deprecate python MessageFactory

Soft deprecate python MessageFactory. Added new replacement APIs GetMessageClass(descriptor) and GetMessagesFromFiles(files, pool)

PiperOrigin-RevId: 501802633

python/google/protobuf/internal/decoder.py

@@ -806,8 +806,7 @@ def DecodeItem(buffer, pos, end, message, field_dict):
       if value is None:
         message_type = extension.message_type
         if not hasattr(message_type, '_concrete_class'):
-          # pylint: disable=protected-access
-          message._FACTORY.GetPrototype(message_type)
+          message_factory.GetMessageClass(message_type)
         value = field_dict.setdefault(
             extension, message_type._concrete_class())
       if value._InternalParse(buffer, message_start,message_end) != message_end:

python/google/protobuf/internal/extension_dict.py

@@ -89,8 +89,9 @@ def __getitem__(self, extension_handle):
     elif extension_handle.cpp_type == FieldDescriptor.CPPTYPE_MESSAGE:
       message_type = extension_handle.message_type
       if not hasattr(message_type, '_concrete_class'):
-        # pylint: disable=protected-access
-        self._extended_message._FACTORY.GetPrototype(message_type)
+        # pylint: disable=g-import-not-at-top
+        from google.protobuf import message_factory
+        message_factory.GetMessageClass(message_type)
       assert getattr(extension_handle.message_type, '_concrete_class', None), (
           'Uninitialized concrete class found for field %r (message type %r)'
           % (extension_handle.full_name,

python/google/protobuf/internal/message_factory_test.py

@@ -92,36 +92,17 @@ def testGetPrototype(self):
     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(
+    cls = message_factory.GetMessageClass(pool.FindMessageTypeByName(
         'google.protobuf.python.internal.Factory2Message'))
     self.assertFalse(cls is factory_test2_pb2.Factory2Message)
     self._ExerciseDynamicClass(cls)
-    cls2 = factory.GetPrototype(pool.FindMessageTypeByName(
+    cls2 = message_factory.GetMessageClass(pool.FindMessageTypeByName(
         'google.protobuf.python.internal.Factory2Message'))
     self.assertTrue(cls is cls2)
 
-  def testCreatePrototypeOverride(self):
-    class MyMessageFactory(message_factory.MessageFactory):
-
-      def CreatePrototype(self, descriptor):
-        cls = super(MyMessageFactory, self).CreatePrototype(descriptor)
-        cls.additional_field = 'Some value'
-        return cls
-
-    db = descriptor_database.DescriptorDatabase()
-    pool = descriptor_pool.DescriptorPool(db)
-    db.Add(self.factory_test1_fd)
-    db.Add(self.factory_test2_fd)
-    factory = MyMessageFactory()
-    cls = factory.GetPrototype(pool.FindMessageTypeByName(
-        'google.protobuf.python.internal.Factory2Message'))
-    self.assertTrue(hasattr(cls, 'additional_field'))
-
   def testGetExistingPrototype(self):
-    factory = message_factory.MessageFactory()
     # Get Existing Prototype should not create a new class.
-    cls = factory.GetPrototype(
+    cls = message_factory.GetMessageClass(
         descriptor=factory_test2_pb2.Factory2Message.DESCRIPTOR)
     msg = factory_test2_pb2.Factory2Message()
     self.assertIsInstance(msg, cls)
@@ -181,15 +162,14 @@ def testGetMessages(self):
 
   def testDuplicateExtensionNumber(self):
     pool = descriptor_pool.DescriptorPool()
-    factory = message_factory.MessageFactory(pool=pool)
 
     # Add Container message.
     f = descriptor_pb2.FileDescriptorProto(
         name='google/protobuf/internal/container.proto',
         package='google.protobuf.python.internal')
     f.message_type.add(name='Container').extension_range.add(start=1, end=10)
     pool.Add(f)
-    msgs = factory.GetMessages([f.name])
+    msgs = message_factory.GetMessageClassesForFiles([f.name], pool)
     self.assertIn('google.protobuf.python.internal.Container', msgs)
 
     # Extend container.
@@ -205,7 +185,7 @@ def testDuplicateExtensionNumber(self):
         type_name='Extension',
         extendee='Container')
     pool.Add(f)
-    msgs = factory.GetMessages([f.name])
+    msgs = message_factory.GetMessageClassesForFiles([f.name], pool)
     self.assertIn('google.protobuf.python.internal.Extension', msgs)
 
     # Add Duplicate extending the same field number.
@@ -223,7 +203,7 @@ def testDuplicateExtensionNumber(self):
     pool.Add(f)
 
     with self.assertRaises(Exception) as cm:
-      factory.GetMessages([f.name])
+      message_factory.GetMessageClassesForFiles([f.name], pool)
 
     self.assertIn(str(cm.exception),
                   ['Extensions '
@@ -281,8 +261,8 @@ def FindFileByName(self, name):
     db = SimpleDescriptorDB({f1.name: f1, f2.name: f2, f3.name: f3})
 
     pool = descriptor_pool.DescriptorPool(db)
-    factory = message_factory.MessageFactory(pool=pool)
-    msgs = factory.GetMessages([f1.name, f3.name])  # Deliberately not f2.
+    msgs = message_factory.GetMessageClassesForFiles(
+        [f1.name, f3.name], pool)  # Deliberately not f2.
     msg = msgs['google.protobuf.python.internal.Container']
     desc = msgs['google.protobuf.python.internal.Extension'].DESCRIPTOR
     ext1 = desc.file.extensions_by_name['top_level_extension_field']
@@ -293,8 +273,8 @@ def FindFileByName(self, name):
     serialized = m.SerializeToString()
 
     pool = descriptor_pool.DescriptorPool(db)
-    factory = message_factory.MessageFactory(pool=pool)
-    msgs = factory.GetMessages([f1.name, f3.name])  # Deliberately not f2.
+    msgs = message_factory.GetMessageClassesForFiles(
+        [f1.name, f3.name], pool)  # Deliberately not f2.
     msg = msgs['google.protobuf.python.internal.Container']
     desc = msgs['google.protobuf.python.internal.Extension'].DESCRIPTOR
     ext1 = desc.file.extensions_by_name['top_level_extension_field']

python/google/protobuf/json_format.py

@@ -53,6 +53,7 @@
 
 from google.protobuf.internal import type_checkers
 from google.protobuf import descriptor
+from google.protobuf import message_factory
 from google.protobuf import symbol_database
 
 
@@ -409,7 +410,7 @@ def _CreateMessageFromTypeUrl(type_url, descriptor_pool):
     raise TypeError(
         'Can not find message descriptor by type_url: {0}'.format(type_url)
       ) from e
-  message_class = db.GetPrototype(message_descriptor)
+  message_class = message_factory.GetMessageClass(message_descriptor)
   return message_class()
 
 

python/google/protobuf/message_factory.py

@@ -39,6 +39,8 @@
 
 __author__ = 'matthewtoia@google.com (Matt Toia)'
 
+import warnings
+
 from google.protobuf.internal import api_implementation
 from google.protobuf import descriptor_pool
 from google.protobuf import message
@@ -53,6 +55,95 @@
 _GENERATED_PROTOCOL_MESSAGE_TYPE = message_impl.GeneratedProtocolMessageType
 
 
+def GetMessageClass(descriptor):
+  """Obtains a proto2 message class based on the passed in descriptor.
+
+  Passing a descriptor with a fully qualified name matching a previous
+  invocation will cause the same class to be returned.
+
+  Args:
+    descriptor: The descriptor to build from.
+
+  Returns:
+    A class describing the passed in descriptor.
+  """
+  concrete_class = getattr(descriptor, '_concrete_class', None)
+  if concrete_class:
+    return concrete_class
+  return _InternalCreateMessageClass(descriptor)
+
+
+def GetMessageClassesForFiles(files, pool):
+  """Gets all the messages from specified files.
+
+  This will find and resolve dependencies, failing if the descriptor
+  pool cannot satisfy them.
+
+  Args:
+    files: The file names to extract messages from.
+    pool: The descriptor pool to find the files including the dependent
+      files.
+
+  Returns:
+    A dictionary mapping proto names to the message classes.
+  """
+  result = {}
+  for file_name in files:
+    file_desc = pool.FindFileByName(file_name)
+    for desc in file_desc.message_types_by_name.values():
+      result[desc.full_name] = GetMessageClass(desc)
+
+    # While the extension FieldDescriptors are created by the descriptor pool,
+    # the python classes created in the factory need them to be registered
+    # explicitly, which is done below.
+    #
+    # The call to RegisterExtension will specifically check if the
+    # extension was already registered on the object and either
+    # ignore the registration if the original was the same, or raise
+    # an error if they were different.
+
+    for extension in file_desc.extensions_by_name.values():
+      extended_class = GetMessageClass(extension.containing_type)
+      extended_class.RegisterExtension(extension)
+      # Recursively load protos for extension field, in order to be able to
+      # fully represent the extension. This matches the behavior for regular
+      # fields too.
+      if extension.message_type:
+        GetMessageClass(extension.message_type)
+  return result
+
+
+def _InternalCreateMessageClass(descriptor):
+  """Builds a proto2 message class based on the passed in descriptor.
+
+  Args:
+    descriptor: The descriptor to build from.
+
+  Returns:
+    A class describing the passed in descriptor.
+  """
+  descriptor_name = descriptor.name
+  result_class = _GENERATED_PROTOCOL_MESSAGE_TYPE(
+      descriptor_name,
+      (message.Message,),
+      {
+          'DESCRIPTOR': descriptor,
+          # If module not set, it wrongly points to message_factory module.
+          '__module__': None,
+      })
+  for field in descriptor.fields:
+    if field.message_type:
+      GetMessageClass(field.message_type)
+  for extension in result_class.DESCRIPTOR.extensions:
+    extended_class = GetMessageClass(extension.containing_type)
+    extended_class.RegisterExtension(extension)
+    if extension.message_type:
+      GetMessageClass(extension.message_type)
+  return result_class
+
+
+# Deprecated. Please use GetMessageClass() or GetMessageClassesForFiles()
+# method above instead.
 class MessageFactory(object):
   """Factory for creating Proto2 messages from descriptors in a pool."""
 
@@ -72,44 +163,29 @@ def GetPrototype(self, descriptor):
     Returns:
       A class describing the passed in descriptor.
     """
-    concrete_class = getattr(descriptor, '_concrete_class', None)
-    if concrete_class:
-      return concrete_class
-    result_class = self.CreatePrototype(descriptor)
-    return result_class
+    # TODO(b/258832141): add this warning
+    # warnings.warn('MessageFactory class is deprecated. Please use '
+    #               'GetMessageClass() instead of MessageFactory.GetPrototype. '
+    #               'MessageFactory class will be removed after 2024.')
+    return GetMessageClass(descriptor)
 
   def CreatePrototype(self, descriptor):
     """Builds a proto2 message class based on the passed in descriptor.
 
     Don't call this function directly, it always creates a new class. Call
-    GetPrototype() instead. This method is meant to be overridden in subblasses
-    to perform additional operations on the newly constructed class.
+    GetMessageClass() instead.
 
     Args:
       descriptor: The descriptor to build from.
 
     Returns:
       A class describing the passed in descriptor.
     """
-    descriptor_name = descriptor.name
-    result_class = _GENERATED_PROTOCOL_MESSAGE_TYPE(
-        descriptor_name,
-        (message.Message,),
-        {
-            'DESCRIPTOR': descriptor,
-            # If module not set, it wrongly points to message_factory module.
-            '__module__': None,
-        })
-    result_class._FACTORY = self  # pylint: disable=protected-access
-    for field in descriptor.fields:
-      if field.message_type:
-        self.GetPrototype(field.message_type)
-    for extension in result_class.DESCRIPTOR.extensions:
-      extended_class = self.GetPrototype(extension.containing_type)
-      extended_class.RegisterExtension(extension)
-      if extension.message_type:
-        self.GetPrototype(extension.message_type)
-    return result_class
+    # TODO(b/258832141): add this warning
+    # warnings.warn('Directly call CreatePrototype is wrong. Please use '
+    #               'GetMessageClass() method instead. Directly use '
+    #               'CreatePrototype will raise error after July 2023.')
+    return _InternalCreateMessageClass(descriptor)
 
   def GetMessages(self, files):
     """Gets all the messages from a specified file.
@@ -125,37 +201,20 @@ def GetMessages(self, files):
       any dependent messages as well as any messages defined in the same file as
       a specified message.
     """
-    result = {}
-    for file_name in files:
-      file_desc = self.pool.FindFileByName(file_name)
-      for desc in file_desc.message_types_by_name.values():
-        result[desc.full_name] = self.GetPrototype(desc)
-
-      # While the extension FieldDescriptors are created by the descriptor pool,
-      # the python classes created in the factory need them to be registered
-      # explicitly, which is done below.
-      #
-      # The call to RegisterExtension will specifically check if the
-      # extension was already registered on the object and either
-      # ignore the registration if the original was the same, or raise
-      # an error if they were different.
-
-      for extension in file_desc.extensions_by_name.values():
-        extended_class = self.GetPrototype(extension.containing_type)
-        extended_class.RegisterExtension(extension)
-        if extension.message_type:
-          self.GetPrototype(extension.message_type)
-    return result
-
-
-_FACTORY = MessageFactory()
+    # TODO(b/258832141): add this warning
+    # warnings.warn('MessageFactory class is deprecated. Please use '
+    #               'GetMessageClassesForFiles() instead of '
+    #               'MessageFactory.GetMessages(). MessageFactory class '
+    #               'will be removed after 2024.')
+    return GetMessageClassesForFiles(files, self.pool)
 
 
-def GetMessages(file_protos):
+def GetMessages(file_protos, pool=None):
   """Builds a dictionary of all the messages available in a set of files.
 
   Args:
     file_protos: Iterable of FileDescriptorProto to build messages out of.
+    pool: The descriptor pool to add the file protos.
 
   Returns:
     A dictionary mapping proto names to the message classes. This will include
@@ -164,13 +223,15 @@ def GetMessages(file_protos):
   """
   # The cpp implementation of the protocol buffer library requires to add the
   # message in topological order of the dependency graph.
+  des_pool = pool or descriptor_pool.DescriptorPool()
   file_by_name = {file_proto.name: file_proto for file_proto in file_protos}
   def _AddFile(file_proto):
     for dependency in file_proto.dependency:
       if dependency in file_by_name:
         # Remove from elements to be visited, in order to cut cycles.
         _AddFile(file_by_name.pop(dependency))
-    _FACTORY.pool.Add(file_proto)
+    des_pool.Add(file_proto)
   while file_by_name:
     _AddFile(file_by_name.popitem()[1])
-  return _FACTORY.GetMessages([file_proto.name for file_proto in file_protos])
+  return GetMessageClassesForFiles(
+      [file_proto.name for file_proto in file_protos], des_pool)