Fix Windows CI

[mbrandonw]

No description provided.

[stephencelis]

@compnerd Sorry to bother you again, but we're looking into fixing our Windows CI again and tried passing the -windows-sdk-version flag and it's not being recognized.

I did a cursory search on GitHub code but couldn't find any invocations, just Swift source that shows the option's definition. Are we holding things wrong?

[stephencelis]

@compnerd I think I figured it out via -Xswiftc flags, but per your comment here I'm getting the same failure output even when pointing at an older WinSDK.

[compnerd]

@compnerd I think I figured it out via -Xswiftc flags, but per your comment here I'm getting the same failure output even when pointing at an older WinSDK.

Sadly there was a bug in the implementation and the flag on its own won’t take effect without -windows-sdk-root. This is fixed in main, but for stable toolchains, it is still required.

There was another clang issue that was uncovered in the process of fixing that, but hitting it is somewhat non-deterministic. I’ve resolved the support for i128 suffixes in clang on main (clang 22), but, that still will need a newer clang to be pulled in :( I would suggest trying it and perhaps it will work for you.

I’m hoping that a set of changes might be possible to repair the modules build with the older clang, but, haven’t gotten that fully worked out yet.

[stephencelis]

@compnerd Sorry, this is a little outside my wheelhouse and I'm not sure I understand. We'd definitely take a PR from someone with more Windows experience to fix things, but as it stands I think we'll probably have to disable Windows CI on all our projects.