HTTPException is not picklable

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Example Code

import pickle
import unittest
from fastapi import HTTPException

def pickle_reduce(self):
    return (HTTPException, (self.status_code, self.detail))

#uncomment to fix
#HTTPException.__reduce__ = pickle_reduce



class TestModelStats(unittest.TestCase):
    def test_pickle_exc_http(self): # this will fail
        pbytes = pickle.dumps(
            HTTPException(status_code = 404, detail="Not found")
        )
        obj = pickle.loads(pbytes) 
        print(type(obj), obj)

Description

This can be worked around using the above

see: # make this unpicklable # python - How to make a custom exception class with multiple init args pickleable - Stack Overflow # noqa # https://stackoverflow.com/questions/16244923/how-to-make-a-custom-exception-class-with-multiple-init-args-pickleable/36342588#36342588

----------------------------------------------------------------------

Traceback (most recent call last): File “test.py”, line 30, in test_pickle_exc_http obj = pickle.loads(pbytes) TypeError: init() missing 1 required positional argument: ‘status_code’

Operating System

Linux

Operating System Details

No response

FastAPI Version

0.85.0

Python Version

Python 3.8.10

Additional Context

see also another related complaint online

https://pythontechworld.com/issue/encode/starlette/1663

[iudeen]

I checked, there is no need for a PR. (A PR on this was already rejected.)

You can check for a solution here: https://github.com/encode/starlette/discussions/1669

[davidgrohmann]

i discovered this while throwing httpexception from multiprocessing worker