GeezerVison

Why not using the qualified name for type(func)?

Would it be possible to also add the module, except for builtin functions?

Why not using the qualified name for type(func)?

I decided to use str(func) as fallback, which looks more useful than f"{type(func)} object".

I consider this a regression: the message is now too similar to calling the method on an instance, but missing an argument.

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: set.add() takes exactly one argument (0 given)

>>> set.add()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: set.add() needs an argument

Agree, this is confusing.

I can change the error message to anything you like, except that it must contain the string set.add (the function name). So it could be

TypeError: unbound method set.add() needs an argument

or whatever (surely, this is better than anything mentioning descriptors).

Small rant: the bug is really this:

>>> set().add()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: add() takes exactly one argument (0 given)

For a Python method, it would correctly note that 2 arguments are required. This is difficult to fix in CPython since builtin_function_or_method doesn't really know whether it's a function or method. This was one of the things that the rejected PEP 580 would have addressed.

Returning __qualname__ without module is not particularly useful.

If you want to return a full qualified name (long but unambiguous), return __module__ + '.' + __qualname__. __module__ can be omitted if it is 'builtins'.

If you want to return a short name (it is enough in many times), return __name__.

if __qualname__ is not available, you can use __name__ instead.

if __qualname__ is not available, you can use __name__ instead.

This is mainly meant as replacement for PyEval_GetFuncName and all classes supported by that function implement __qualname__. So I see little reason for the additional complexity of supporting __name__.

Agree, this is confusing.