gh-36488: Fix func_persist: do not use the (now removed) inspect.formatargspec, but instead use inspect.signature.
Fix func_persist: do not use inspect.formatargspec (gone as of Python
3.11)
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The method `inspect.formatargspec` has been deprecated since Python 3.5,
now removed as of 3.11. `func_persist` still uses it, so we replace it
with `inspect.signature`.
Another option would be to replace it with
`sageinspect.sage_formatargspec`. I think that func_persist should only
be used with Python functions, not Cython, and `inspect.signature` is
nicer for Python functions. If the function is defined as `def test(n:
int) -> int:`, For example, then `inspect.signature` will return `(n:
int) -> int` while `sageinspect.sage_formatargspec` will just return
`(n)`.
This should fix #36302.
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URL: https://github.com/sagemath/sage/pull/36488
Reported by: John H. Palmieri
Reviewer(s): balejk
