UP006: Incorrect autofix when shadowing builtin

[jdahlin]

The autofix for UP006 is not working correctly when shadowing a builtin such as type.

Test case

from typing import Type

class F:
    type = "abc"
    def foo(self) -> Type[list]:
        return list

Expected code after autofix:

import builtins


class F:
    type = "abc"
    def foo() -> builtins.type[list]:
        return list

Actual code after autofix:

class F:
    type = "abc"
    def foo() -> type[list]:
        return list

[charliermarsh]

Thanks, you're right! These should check for redefined builtins.

[jdahlin]

Wow, thanks for the quick fix! Should I open up a new issue to handle the case when the builtins are overriden/shadowed?

[charliermarsh]

What do you think the ideal behavior would be in that case?

[jdahlin]

What do you think the ideal behavior would be in that case?

To fetch the original object via the builtin module, e.g:

import builtins


class F:
    type = "abc"
    def foo() -> builtins.type[list]:
        return list

[charliermarsh]

Yeah we can open an issue for that. It will be tricky to do right now because fixes can't introduce new imports. So for now, we could support this in the event that a module already imports builtins, but we couldn't "import builtins and change the reference". (Part of #835.)

[jdahlin]

@charliermarsh original builtins can also be found in __builtins__ which is always present in the current globals.

[charliermarsh]

@jdahlin - True! Although that can also be overridden 😂 Feel free to open an issue for it :)