stubgen: mangles from _typeshed import Incomplete on Windows

[Josverl]

Bug Report When stubgen creates stubs for a module that imports Incomplete , it then mangles / overcomplicates the import in the generated stub edit : On Windows

To Reproduce - minimal repro

from _typeshed import Incomplete


def polar(*args, **kwargs) -> Incomplete:
    ...

running stubgen results in

from _typeshed import Incomplete as Incomplete

def polar(*args, **kwargs) -> Incomplete: ...

Environment

• Mypy version used: 1.7.0
• Mypy command-line flags: - none
• Mypy configuration options from mypy.ini (and other config files): None
• Python version used: 3.11
• OS: Windows_NT x64 10.0.26100

[makridenko]

@Josverl hi! I think it's outdated issue

[Josverl]

I can prove it still reproduces with stubgen 1.15.0.

@makridenko Why do you think it is outdated ?

[makridenko]

@Josverl I've tried to reproduce it with master-branch stubgen and it works fine. I guess we need to wait for release

[Josverl]

Perhaps to be clearer The bug is the 2x Incomplete in Incomplete as Incomplete

Expected

from _typeshed import Incomplete

def polar(*args, **kwargs) -> Incomplete

So the bug is still not resolved.

[makridenko]

In master branch everything is working as expected:

[sobolevn]

Do we have a test case for that?

[makridenko]

@sobolevn I can add the test that's in the screenshot above

[makridenko]

@sobolevn https://github.com/python/mypy/pull/19253

[Josverl]

Ill verify the current state as I can't explain why the behavior is different for @makridenko than for me. Also the previous reported behavior by @makridenko was same as mine, so something changed....

That might also mean that the test case is not covering the all relevant aspects.

Ill report back here.

[Josverl]

@sobolevn Im sorry , but i need to report that the issue indeed is not fixed. The same issue still occurs, but appears to be specific to stubgen running on Windows. I did not include that in my initial report, as I assumed that that would not matter.

Is stubgen tested on anything but Ubuntu ? ( there are a lot of tests skipped on Windows)

See : https://github.com/Josverl/mypy_mangle

[makridenko]

@Josverl thank you for clarifying this, unfortunately I don't have any windows machine. @sobolevn could you test this?

[Josverl]

a few points.

1. The tests that was added is part of a suite that is skipped on Windows. ( along with the rest of the suite)

        
        pytest  mypy\test\teststubgen.py::StubgenPythonSuite::stubgen.test::testIncompleteReturn
        ========================================================================= test session starts ==========================================================================
        platform win32 -- Python 3.11.9, pytest-8.3.5, pluggy-1.5.0
        rootdir: D:\mypython\!-stubtestprojects\mypy_mangle\mypy
        configfile: pyproject.toml
        plugins: anyio-4.6.0, time-machine-2.16.0
        collected 1 item                                                                                                                                                        
        
        mypy\test\teststubgen.py s                                                                                                                                        [100%] 
        
        ========================================================================== 1 skipped in 0.44s ==========================================================================

2. When I remove that skipif guard , the tests passes, but the stubgen behaviour is still incorrect.

[Josverl]

Any progress on replication of this issue?