id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
36094	A PicklingError occurs when using Django channels together with a logging SocketHandler, if an HTTP error status is returned.	Vinay Sajip		"Assume that the logging configuration includes a `logging.handlers.SocketHandler`. When a view returns an HTTP error status such as 400, the behavior is different according to whether or not channels are in use. When channels are ''not'' in use, you get this printed on the console:

{{{
Bad Request: /fail/400
[13/Jan/2025 21:39:04] ""GET /fail/400 HTTP/1.1"" 400 26314
}}}

Well and good. However, if channels ''are'' in use, you get this:

{{{
Bad Request: /fail/400
--- Logging error ---
Traceback (most recent call last):
  File ""/usr/lib/python3.10/logging/handlers.py"", line 677, in emit
    s = self.makePickle(record)
  File ""/usr/lib/python3.10/logging/handlers.py"", line 649, in makePickle
    s = pickle.dumps(d, 1)
  File ""/home/vinay/.local/share/virtualenvs/django-base/lib/python3.10/site-packages/django/urls/resolvers.py"", line 105, in __reduce_ex__
    raise PicklingError(f""Cannot pickle {self.__class__.__qualname__}."")
_pickle.PicklingError: Cannot pickle ResolverMatch.
Call stack:
  File ""/usr/lib/python3.10/threading.py"", line 973, in _bootstrap
    self._bootstrap_inner()
  File ""/usr/lib/python3.10/threading.py"", line 1016, in _bootstrap_inner
    self.run()
  File ""/usr/lib/python3.10/threading.py"", line 953, in run
    self._target(*self._args, **self._kwargs)
  File ""/usr/lib/python3.10/concurrent/futures/thread.py"", line 83, in _worker
    work_item.run()
  File ""/usr/lib/python3.10/concurrent/futures/thread.py"", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
  File ""/home/vinay/.local/share/virtualenvs/django-base/lib/python3.10/site-packages/asgiref/sync.py"", line 522, in thread_handler
    return func(*args, **kwargs)
  File ""/home/vinay/.local/share/virtualenvs/django-base/lib/python3.10/site-packages/django/utils/log.py"", line 248, in log_response
    getattr(logger, level)(
Message: '%s: %s'
Arguments: ('Bad Request', '/fail/400')
HTTP GET /fail/400 400 [0.24, 127.0.0.1:49610]
}}}

The reason appears to be due to this code in `django.utils.log.py`, in function `log_response`:
{{{
    getattr(logger, level)(
        message,
        *args,
        extra={
            ""status_code"": response.status_code,
            ""request"": request,
        },
        exc_info=exception,
    )
}}}

The difference between the channels case and the other is that in the channels case, the `extra` dictionary contains the `request` key points to an instance of `django.core.handlers.asgi.ASGIRequest`, whereas in the non-channels case the `request` key points to an instance of `django.core.handlers.wsgi.WSGIRequest`. In the WSGI request handling path, the `resolver_match` attribute of the request is not changed after being initialized to `None`, whereas in the ASGI request handling path, the `resolver_match` attribute is set to a `ResolverMatch` instance, which is not pickleable, and leads to the above traceback.

Furthermore, when looking at this problem, the `ASGIRequest.__init__` sets the `resolver_match` attribute to `None` twice. Either one of those is redundant, or a comment is needed to say why the two set statements are present."	Bug	closed	Core (Other)	5.1	Normal	invalid			Unreviewed	0	0	0	0	0	0