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3.13.0b3 regression: inspect.signature + unittest.mock #121257
Description
Bug report
Bug description:
MRE:
import inspect
import functools
from unittest import TestCase
import unittest.mock as mk
class TestIsinstance(TestCase):
def test_mk(self):
def foo(): pass
with mk.patch.object(functools, "partial", autospec=True):
inspect.signature(foo)fails with
E
======================================================================
ERROR: test_mk (test.TestIsinstance.test_mk)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/private/tmp/reprod/test.py", line 10, in test_mk
inspect.signature(foo)
~~~~~~~~~~~~~~~~~^^^^^
File "/Users/clm/.pyenv/versions/3.13.0b3/lib/python3.13/inspect.py", line 3333, in signature
return Signature.from_callable(obj, follow_wrapped=follow_wrapped,
~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
globals=globals, locals=locals, eval_str=eval_str)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/clm/.pyenv/versions/3.13.0b3/lib/python3.13/inspect.py", line 3059, in from_callable
return _signature_from_callable(obj, sigcls=cls,
follow_wrapper_chains=follow_wrapped,
globals=globals, locals=locals, eval_str=eval_str)
File "/Users/clm/.pyenv/versions/3.13.0b3/lib/python3.13/inspect.py", line 2559, in _signature_from_callable
if isinstance(obj, functools.partial):
~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: isinstance() arg 2 must be a type, a tuple of types, or a union
----------------------------------------------------------------------
Ran 1 test in 0.002s
FAILED (errors=1)
reproduces locally and in CI: example logs
this test case is adapted from a real life application in astropy's test suite, which has been stable since at least Python 3.8
CPython versions tested on:
3.8, 3.9, 3.10, 3.11, 3.12, 3.13
Operating systems tested on:
Linux, macOS, Windows
Activity
[-]3.13.0b3 regression: [/-][+]3.13.0b3 regression: inspect.signature + unittest.mock[/+]picnixz commentedon Jul 2, 2024
Could it be because of #121092? (especially: https://github.com/python/cpython/pull/121092/files#diff-b89cd06e4637abacb73f2500301ff979a67ad7ecbfa7cf151c7243715898d7eaL2570-L2573)
neutrinoceros commentedon Jul 2, 2024
Thank you ! It's definitely related: the test pass if I revert just the bit you pointed to.
picnixz commentedon Jul 2, 2024
cc @serhiy-storchaka
serhiy-storchaka commentedon Jul 2, 2024
It is not safe to patch
functools.partialwhich is used in theinspectmodule and then use theinspectmodule.Add the following code in your example and you will see that it was broken before #121092.
neutrinoceros commentedon Jul 2, 2024
Thanks for pointing this out !
I was able to resolve this on our side by avoiding mocking altogether at astropy/astropy#16659
Feel free to close this issue.