Hi there, has anyone faced something like this before?

Unexpected error: TypeError('no default __reduce__ due to non-trivial __cinit__')
Traceback (most recent call last):
  File "/opt/venv/lib/python3.9/site-packages/prefect/engine/runner.py", line 48, in inner
    new_state = method(self, state, *args, **kwargs)
  File "/opt/venv/lib/python3.9/site-packages/prefect/engine/task_runner.py", line 926, in get_task_run_state
    result = self.result.write(value, **formatting_kwargs)
  File "/opt/venv/lib/python3.9/site-packages/prefect/engine/results/gcs_result.py", line 75, in write
    binary_data = new.serializer.serialize(new.value)
  File "/opt/venv/lib/python3.9/site-packages/prefect/engine/serializers.py", line 73, in serialize
    return cloudpickle.dumps(value)
  File "/opt/venv/lib/python3.9/site-packages/cloudpickle/cloudpickle_fast.py", line 73, in dumps
    cp.dump(obj)
  File "/opt/venv/lib/python3.9/site-packages/cloudpickle/cloudpickle_fast.py", line 602, in dump
    return Pickler.dump(self, obj)
  File "stringsource", line 2, in pymssql._mssql.MSSQLConnection.__reduce_cython__
TypeError: no default __reduce__ due to non-trivial __cinit__

I'm using Prefect 0.15.9 and pymssql 2.2.3. The task that raised it is the following

@task
def sql_server_get_connection(server: str, user: str, password: str, database: str):
    """
    Returns a connection to the SQL Server.
    """
    log(f"Connecting to SQL Server: {server}")
    # pylint: disable=E1101
    return pymssql.connect(
        server=server, user=user, password=password, database=database
    )

The issue here is Prefect saves results by default and serialized them. You need to turn off checkpointing if you are returning a connection because it can’t be serialized

@task(checkpoint=False)

awesome! thanks for the quick response, I'll try that out!