functools.partial objects have no __qualname__ attribute. This means, for example, that code expecting a callable that logs the __qualname__ attribute can break when passed a functools.partial object.

Example:

>>> import functools
>>> int.__qualname__
'int'
>>> p = functools.partial(int)
>>> p.__qualname__
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'functools.partial' object has no attribute '__qualname__'

the functools.partial returns an instance not fun or cls.using `p.func.__qualname__` may be you want.

Using p.func would name the function passed to functools.partial() rather than the partial object itself.

It seems __repr__ call to partial object has qualname but I think it always returns "partial". Ref : https://github.com/python/cpython/blob/0afada163c7ef25c3a9d46ed445481fb69f2ecaf/Lib/functools.py#L276

>>> import functools
>>> int.__qualname__
'int'
>>> p = functools.partial(int)
>>> p.__qualname__
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'functools.partial' object has no attribute '__qualname__'
>>> p
functools.partial(<class 'int'>)


Thanks

partial() return an instance not class or function. Why it need __qualname__ attribute?

Ref: https://www.python.org/dev/peps/pep-3155/

I don't see a problem. Not all callables have the __qualname__ attribute. It is not the part of the protocol. The code that expects the __qualname__ attribute should be fixed.

Okay, I thought a partial object was supposed to "look" like a function.

I'm okay with closing this.

partial objects lack many other function attributes: __name__, __module__ (and __qualname__ doesn't make sense without __module__),  __annotations__, __get__(), etc. It would be nice to make these types more similar, but attributes shouldn't lie. And I am not sure what partial.__qualname__ can be. It shouldn't be the __qualname__ of the wrapped function, since the partial object differs from it, and is not accessible by same name.

> It shouldn't be the __qualname__ of the wrapped function

Yes, I agree with you. I was thinking it should be similar to what it would be for a function defined at the same location.

functools.partial objects have no __qualname__ attribute, but they don't have a __name__ attribute neither.

$ python3
Python 3.6.6 (default, Jul 19 2018, 14:25:17) 
>>> import functools
>>> func=int
>>> p=functools.partial(func)
>>> p.__name__
AttributeError: 'functools.partial' object has no attribute '__name__'
>>> p.__qualname__
AttributeError: 'functools.partial' object has no attribute '__qualname__'
>>> repr(p)
"functools.partial(<class 'int'>)"

If you want to "inherit" the name of the "wrapped function", you may use: functools.update_wrapper().

I'm not sure that it's correct to inherit the name by default. functools.partial() creates a new function, so if it has a name, for me, it should be different.

I agree to close the issue, it's not a bug.

Sorry, I'm out of practice. I thought I closed this when I marked it rejected.