BUG: Incorrect signatures for np.random functions when NumPy built with Cython 0.29 #24429
Description
Describe the issue:
When NumPy 1.26.0b1 is built with Cython 0.29, inspect.signature returns an inaccurate signature for Cython functions, e.g., in np.random.
With 1.26.0b1 built with Cython 0.29.36:
In [1]: import numpy as np, inspect
In [2]: inspect.signature(np.random.poisson)
Out[2]: <Signature (lam, size)>
If Cython 3.0 is used, the signature is correct:
In [1]: import numpy as np, inspect
In [2]: inspect.signature(np.random.poisson)
Out[2]: <Signature (lam=1.0, size=None)>
In particular, this breaks tests that use mock.patch.object to patch np.random functions, e.g. this no longer works:
In [1]: import numpy as np, inspect
In [2]: from unittest import mock
In [3]: m = mock.patch.object(np.random, "poisson", autospec=True).start()
In [4]: np.random.poisson(lam=0.5)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
Cell In[4], line 1
----> 1 np.random.poisson(lam=0.5)
File <string>:2, in poisson(*args, **kwargs)
File ~/.pyenv/versions/3.11.0/lib/python3.11/unittest/mock.py:185, in _set_signature.<locals>.checksig(*args, **kwargs)
184 def checksig(*args, **kwargs):
--> 185 sig.bind(*args, **kwargs)
File ~/.pyenv/versions/3.11.0/lib/python3.11/inspect.py:3204, in Signature.bind(self, *args, **kwargs)
3199 def bind(self, /, *args, **kwargs):
3200 """Get a BoundArguments object, that maps the passed `args`
3201 and `kwargs` to the function's signature. Raises `TypeError`
3202 if the passed arguments can not be bound.
3203 """
-> 3204 return self._bind(args, kwargs)
File ~/.pyenv/versions/3.11.0/lib/python3.11/inspect.py:3174, in Signature._bind(self, args, kwargs, partial)
3167 except KeyError:
3168 # We have no value for this parameter. It's fine though,
3169 # if it has a default value, or it is an '*args'-like
3170 # parameter, left alone by the processing of positional
3171 # arguments.
3172 if (not partial and param.kind != _VAR_POSITIONAL and
3173 param.default is _empty):
-> 3174 raise TypeError('missing a required argument: {arg!r}'. \
3175 format(arg=param_name)) from None
3177 else:
3178 if param.kind == _POSITIONAL_ONLY:
3179 # This should never happen in case of a properly built
3180 # Signature object (but let's have this check here
3181 # to ensure correct behaviour just in case)
TypeError: missing a required argument: 'size'```
Since no signatures are better than wrong signatures, and Cython 3.0 enables the binding directive by default anyway (https://cython.readthedocs.io/en/latest/src/userguide/migrating_to_cy30.html#binding-functions), might I suggest reverting #21975 ? The distributed NumPy wheels are built with Cython 3.0 anyway, aren't they? So they don't need the binding directive.
Reproduce the code example:
import numpy as np
import inspect
inspect.signature(np.random.poisson)Error message:
See above.Runtime information:
In [1]: import sys, numpy; print(numpy.__version__); print(sys.version)
1.26.0b1
3.11.0 (main, Dec 1 2022, 19:33:09) [GCC 12.2.0]
In [2]: print(numpy.show_runtime())
WARNING: `threadpoolctl` not found in system! Install it by `pip install threadpoolctl`. Once installed, try `np.show_runtime` again for more detailed build information
[{'numpy_version': '1.26.0b1',
'python': '3.11.0 (main, Dec 1 2022, 19:33:09) [GCC 12.2.0]',
'uname': uname_result(system='Linux', node='<redacted>', release='6.3.11-redacted-amd64', version='#1 SMP PREEMPT_DYNAMIC Debian 6.3.11-redacted (2023-07-18)', machine='x86_64')},
{'simd_extensions': {'baseline': ['SSE', 'SSE2', 'SSE3'],
'found': ['SSSE3',
'SSE41',
'POPCNT',
'SSE42',
'AVX',
'F16C',
'FMA3',
'AVX2'],
'not_found': ['AVX512F',
'AVX512CD',
'AVX512_KNL',
'AVX512_KNM',
'AVX512_SKX',
'AVX512_CLX',
'AVX512_CNL',
'AVX512_ICL',
'AVX512_SPR']}}]
None
Context for the issue:
This change breaks approximately 40 tests in our code base.