Wrong error message in broker handler

[asarkhipov]

Describe the bug
When I made a mistake specifying the argument type, I received an error.

To Reproduce
Add source code

from propan import KafkaBroker, PropanApp

broker = KafkaBroker()
app = PropanApp(broker)


class A:
    ...


@broker.handle("test-topic", auto_offset_reset="earliest")
async def hello(msg: str, a: A):
    print(msg)

Result:

2023-06-03 14:49:12,214 ERROR    - Invalid args for response field! Hint: check that <class 'mode.A'> is a valid pydantic field type
2023-06-03 14:49:12,214 ERROR    - Please, input module like [python_file:propan_app_name]

And steps to reproduce the behavior:

1. Run the code

Expected behavior
More informative output, that tell something like "In the main.py file, on line 12, the argument 'a' has type A. It was expected to have type pydantic field and a default value of Depends or Context."

Environment
Running Propan 0.1.2.7 with CPython 3.10.10 on Linux

[Lancetnik]

It's a not Propan error. The framework builds pydantic.BaseModel by your function arguments.

Because the following code is not correct, your function annotation is not correct too.

from pydantic import BaseModel

class A:
   ...

class Model(BaseModel):
    a: A

You should use python primitives or pydantic.BaseModel to annotate your handler arguments.

P.S: the same behavior you can see in FastAPI

[asarkhipov]

I know that my function argument is incorrect, but issue about error messages:
Invalid args for response field! - A is not response field, it is handler argument. If code base is big, this is hard to find there it is being used
Please, input module like [python_file:propan_app_name] - I run it correct, why i get this?

[Lancetnik]

Well, it makes sense