Bug report

Bug description:

Since #106311 its documented in the inspect.signature() sphinx docs as:
"If the passed object has a __signature__ attribute, this function returns it without further computations."

That looks correct per PEP 362, see the implementation section. But actual code logic goes far away from this simple description:

Either we should document this properly (then this is a documentation issue). Or we could change the code and remove undocumented logic. As this attribute was documented recently, I'll suggest the second option.

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Linked PRs

• gh-115937: remove extra processing for the __signature__ attribute #115984
• gh-115937: Remove implementation details from inspect.signature() docs #116086
• [3.12] gh-115937: Remove implementation details from inspect.signature() docs (GH-116086) #116106
• [3.11] gh-115937: Remove implementation details from inspect.signature() docs (GH-116086) #116107