GHC 9.4 Windows regressions in test suite

[ulysses4ever]

Describe the bug

Multiple regressions on Windows with GHC 9.4. They seem to do with the move to the clang toolchain on Windows. Surprising variety.

• PackageTests/ForeignLibs/setup.test.hs
• PackageTests/CCompilerOverride/setup.test.hs
• PackageTests/NewBuild/CmdTest/OptionsFlag/cabal.test.hs
• PackageTests/NewBuild/CmdRun/ScriptWithProjectBlock/cabal.test.hs
• PackageTests/NewBuild/CmdRun/ScriptRerun/cabal.test.hs
• PackageTests/NewBuild/CmdRun/ScriptNoExtension/cabal.test.hs
• PackageTests/NewBuild/CmdRun/ScriptLiterate/cabal.test.hs
• PackageTests/NewBuild/CmdRun/Script/cabal.test.hs
• PackageTests/NewBuild/CmdClean/Script/cabal.test.hs
• PackageTests/NewBuild/CmdClean/Orphan/cabal.test.hs
• PackageTests/NewBuild/CmdClean/Keep/cabal.test.hs
• PackageTests/NewBuild/CmdBuild/ScriptRerun/cabal.test.hs
• PackageTests/NewBuild/CmdBuild/ScriptBuildRun/cabal.test.hs
• PackageTests/NewBuild/CmdBuild/ScriptBuildRepl/cabal.test.hs
• PackageTests/NewBuild/CmdBuild/Script/cabal.test.hs
• PackageTests/NewBuild/CmdBench/OptionsFlag/cabal.test.hs
• PackageTests/FFI/ForeignOptsCxx/cabal.test.hs
• PackageTests/FFI/ForeignOptsC/cabal.test.hs
• PackageTests/CustomPreProcess/cabal.test.hs

Note that the simplest possible cabal script fails on WIndows now:

• PackageTests/NewBuild/CmdBuild/ScriptBuildRun/cabal.test.hs

I reproduced it as a standalone example, without dependency on cabal-master or cabal-testsuite here: https://github.com/ulysses4ever/test-cabal-script-win

It'd be great if people with Windows expertise looked closer into these. But so far we'll have to mark them broken.

/cc @Mistuke @jneira

To Reproduce

$ git clone https://github.com/ulysses4ever/cabal && cd cabal && git checkout adopt-ghc-9.4.1-win-fail
...
$ cabal build cabal cabal-tests
... 
$ cabal run cabal-tests -- --with-cabal="$(cabal list-bin cabal)" cabal-testsuite\PackageTests\ForeignLibs\setup.test.hs
...
$ cabal run cabal-tests -- --with-cabal="$(cabal list-bin cabal)" cabal-testsuite\PackageTests\CCompilerOverride\setup.test.hs

You probably can skip building cabal and run the tests with the host cabal (so, list-bin stuff can be replaced with which cabal); it has to be at least 3.8 on Windows to live happily with GHC 9.4.

System information

• OS: GitHub Actions windows-latest
• GHC 9.4.1

Additional context
Found in #8420. Here's a link to a failed CI run for the first two tests (afaiu it will be gone at some point).

[Mikolaj]

Is this a new one? Or the one discussed a bit elsewhere (if so, could you post a precise link?)?

[ulysses4ever]

Strangely enough, some subset of the failing tests listed in the OP has been fixed in #8898 and yet different subset of them was fixed in the backport of the same PR (#8970).