[issue45218] cmath.log has an invalid signature

[Mark Dickinson]

New submission from Mark Dickinson <dickinsm at gmail.com>:

inspect.signature reports that the cmath.log function has an invalid signature:

Python 3.11.0a0 (heads/fix-44954:d0ea569eb5, Aug 19 2021, 14:59:04) [Clang 12.0.0 (clang-1200.0.32.29)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import cmath
>>> import inspect
>>> inspect.signature(cmath.log)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/mdickinson/Python/cpython/Lib/inspect.py", line 3215, in signature
    return Signature.from_callable(obj, follow_wrapped=follow_wrapped,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mdickinson/Python/cpython/Lib/inspect.py", line 2963, in from_callable
    return _signature_from_callable(obj, sigcls=cls,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mdickinson/Python/cpython/Lib/inspect.py", line 2432, in _signature_from_callable
    return _signature_from_builtin(sigcls, obj,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mdickinson/Python/cpython/Lib/inspect.py", line 2244, in _signature_from_builtin
    return _signature_fromstr(cls, func, s, skip_bound_arg)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/mdickinson/Python/cpython/Lib/inspect.py", line 2114, in _signature_fromstr
    raise ValueError("{!r} builtin has invalid signature".format(obj))
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ValueError: <built-in function log> builtin has invalid signature

----------
components: Extension Modules
messages: 401933
nosy: mark.dickinson
priority: normal
severity: normal
status: open
title: cmath.log has an invalid signature
versions: Python 3.10, Python 3.11, Python 3.9

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue45218>
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