NotImplementedError: Decoder class for "Compact<u32>" not found

[sergpsu]

Hi The exception occurs from time to time in different scenarios but always for Compact<u32> type. Have to mention that few instances of py-substrate-interface is used in parallel in different async tasks. Also it seems that the exception occurs only at the start, so if it does not happen at once then it should not happen ever. We are using py-substrate-interface 1.3.0, scalecodec 1.0.42 and python 3.8 Here are two logs

1. Block subscription

   2022-09-21 18:52:01,654 [ERROR] Future exception was never retrieved
   future: <Future finished exception=NotImplementedError('Decoder class for "Compact<u32>" not found')>
   Traceback (most recent call last):
   File "/usr/lib/python3.8/concurrent/futures/thread.py", line 57, in run
   result = self.fn(*self.args, **self.kwargs)
   File "/app/./ps.py", line 480, in wait_block_finalized
   substrate.isubstrate.subscribe_block_headers( subscription_handler_f, finalized_only=True )
   File "/usr/local/lib/python3.8/dist-packages/substrateinterface/base.py", line 2810, in subscribe_block_headers
   return self.__get_block_handler(
   File "/usr/local/lib/python3.8/dist-packages/substrateinterface/base.py", line 2563, in __get_block_handler
   self.init_runtime(block_hash=block_hash)
   File "/usr/local/lib/python3.8/dist-packages/substrateinterface/base.py", line 1136, in init_runtime
   self.metadata_decoder = self.get_block_metadata(block_hash=runtime_block_hash, decode=True)
   File "/usr/local/lib/python3.8/dist-packages/substrateinterface/base.py", line 940, in get_block_metadata
   metadata_decoder.decode()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 552, in process
   member_obj = self.process_type(member_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 1896, in process
   value = super().process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 1064, in process
   result_obj = self.process_type(enum_type_mapping[1], metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 506, in process
   field_obj = self.process_type(data_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 830, in process
   element = self.process_type(self.sub_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 506, in process
   field_obj = self.process_type(data_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 135, in process
   self.value_object = self.process_type(self.sub_type)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 506, in process
   field_obj = self.process_type(data_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 830, in process
   element = self.process_type(self.sub_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 506, in process
   field_obj = self.process_type(data_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 830, in process
   element = self.process_type(self.sub_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 159, in process
   length = self.process_type('Compact<u32>').value
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 759, in process_type
   obj = self.runtime_config.create_scale_object(type_string, self.data, **kwargs)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 168, in create_scale_object
   raise NotImplementedError('Decoder class for "{}" not found'.format(type_string))
   NotImplementedError: Decoder class for "Compact<u32>" not found

2. substrate_interface.query() call

   future: <Task finished name='IPFS BOOTSTRAP' coro=<ParameterServer.ipfs_bootstrap() done, defined at /app/./ps.py:904> exception=NotImplementedError('Decoder class for "Compact<u32>" not found')>
   Traceback (most recent call last):
   File "/app/./ps.py", line 915, in ipfs_bootstrap
   if not self.substrate.get_vendor(VENDOR_NAME):
   File "/app/./lib/py_substrate/substrate.py", line 857, in get_vendor
   res = self.isubstrate.query(
   File "/usr/local/lib/python3.8/dist-packages/substrateinterface/base.py", line 1361, in query
   self.init_runtime(block_hash=block_hash)
   File "/usr/local/lib/python3.8/dist-packages/substrateinterface/base.py", line 1136, in init_runtime
   self.metadata_decoder = self.get_block_metadata(block_hash=runtime_block_hash, decode=True)
   File "/usr/local/lib/python3.8/dist-packages/substrateinterface/base.py", line 940, in get_block_metadata
   metadata_decoder.decode()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 552, in process
   member_obj = self.process_type(member_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 1896, in process
   value = super().process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 1064, in process
   result_obj = self.process_type(enum_type_mapping[1], metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 506, in process
   field_obj = self.process_type(data_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 506, in process
   field_obj = self.process_type(data_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 830, in process
   element = self.process_type(self.sub_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 506, in process
   field_obj = self.process_type(data_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 506, in process
   field_obj = self.process_type(data_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 1064, in process
   result_obj = self.process_type(enum_type_mapping[1], metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 506, in process
   field_obj = self.process_type(data_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 830, in process
   element = self.process_type(self.sub_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 506, in process
   field_obj = self.process_type(data_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 830, in process
   element = self.process_type(self.sub_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 506, in process
   field_obj = self.process_type(data_type, metadata=self.metadata)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 135, in process
   self.value_object = self.process_type(self.sub_type)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 760, in process_type
   obj.decode(check_remaining=False)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 677, in decode
   self.value_serialized = self.process()
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/types.py", line 159, in process
   length = self.process_type('Compact<u32>').value
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 759, in process_type
   obj = self.runtime_config.create_scale_object(type_string, self.data, **kwargs)
   File "/usr/local/lib/python3.8/dist-packages/scalecodec/base.py", line 168, in create_scale_object
   raise NotImplementedError('Decoder class for "{}" not found'.format(type_string))
   NotImplementedError: Decoder class for "Compact<u32>" not found

[zhoujs93]

Hi, has there been any issue around ? Currently running into the same problem