gh-77589: Add unix domain socket for Windows

[aisk]

Didn't add asyncio support in this PR to avoid too many code changes and keep the review process simpler.

• Issue: Enable AF_UNIX support in Windows #77589

[serhiy-storchaka]

Instead of skipping some tests, would not be worth to test a Windows specific behavior?

Some tests can currently be skipped on Windows, but they may work after adding support of AF_UNIX. Please check all currently skipped tests for socket and multiprocessing.

[serhiy-storchaka]

It seems that the previous attempt did have more changes in the socket and socketserver modules. Are they no longer relevant?

[aisk]

It seems that the previous attempt did have more changes in the socket and socketserver modules. Are they no longer relevant?

The previous attempt modified the socketpair function in the socket module to use AF_UNIX by default on Windows, so it would introduce more changes. I'd like to keep the current behavior to reduce code changes in one PR and compatibility break risk, and we can change it in the future.

The change in socketserver in the previous attempt is mainly because in asyncio's test case, it tries to create an HTTP server over unix domain sockets. On Windows, currently AF_UNIX doesn't support reuse_address, so there needs to be this modification. I changed the test to disable reuse_address on Windows with AF_UNIX. But I think the previous attempt is the right way because users can encounter this issue too. Will update this later today. Thank you for the review!

[aisk]

Instead of skipping some tests, would not be worth to test a Windows specific behavior?

Some tests can currently be skipped on Windows, but they may work after adding support of AF_UNIX. Please check all currently skipped tests for socket and multiprocessing.

Hi, I updated the test to test Windows-specific behaviors, and checked current tests which can be enabled after we added AF_UNIX, but not finding one. Most tests are skipped by some stuff like 'skipUnless(hasattr(socket, "AF_UNIX))'.

There is a noticeable remark for the reviewer: The PC\pyconfig.h is maintained by hand, so we don't have a configure step to detect if current build environment have AF_UNIX support (have afunix.h). So I introduced __has_include which haven't seen in current repository. Please let me know if there are better way to do this.

[github-actions]

This PR is stale because it has been open for 30 days with no activity.

[abel1502]

What's the status of this PR? It seems ready for merge, are there any standing issues?