Can't debug Falcon in Python 3.10

[YossiTamari]

At least in PyCharm, when running in debug mode (so with Type Checking on), in Python 3.10 specifically, importing falcon adds a a property called dict to Python's collections. The property is a dict of media type handlers.
That causes a crash later when collections tries to do dict(...).
(Tested in Falcon 3.1.0: falcon-3.1.0-cp310-cp310-macosx_10_15_x86_64.whl)

To reproduce simply debug this code:

import collections
import falcon
print(collections.dict)

The output when running with a debugger is:

{'application/json': <falcon.media.json.JSONHandler object at 0x120e59ba0>, 'application/x-www-form-urlencoded': <falcon.media.urlencoded.URLEncodedFormHandler object at 0x120e59c00>}

When running without a debugger it correctly raises AttributeError: module 'collections' has no attribute 'dict'

Additional Information: This seems to happen inside falcon/__init__.py in the call to from falcon.app import API. Putting a breakpoint inside falcon.app did not work. For some reason, the debugger would not stop there.

[CaselIT]

Hi,

This is a pycharm bug, I'm not sure how can we fix this our side. The falcon library is not doing that anywhere.

A collegue of mine already reported it on pycharm side https://youtrack.jetbrains.com/issue/PY-54853

[DavideCanton]

You can bypass the problem by deleting the cythonized falcon libraries in the site packages, as a workaround.

[vytas7]

Adding to @DavideCanton's answer, you can also install Falcon without binaries:

FALCON_DISABLE_CYTHON=1 pip install --no-binary=falcon falcon