Cache saving fails on Windows

[eregon]

See https://github.com/ruby/setup-ruby/runs/1370892940?check_suite_focus=true

  Saving cache
  C:\msys64\usr\bin\tar.exe --posix --use-compress-program "zstd -T0" -cf cache.tzst -P -C D:/a/setup-ruby/setup-ruby --files-from manifest.txt --force-local
  /usr/bin/tar: vendor\bundle: Cannot stat: No such file or directory
  /usr/bin/tar: Exiting with failure status due to previous errors
  Warning: Tar failed with error: The process 'C:\msys64\usr\bin\tar.exe' failed with exit code 2

I guess this is due to using MSYS's tar and not one of the other tar.

It seems we get in this branch:
https://github.com/actions/toolkit/blob/e7eb2c741847a05686a1b8df93dea4b244640b17/packages/cache/src/internal/tar.ts#L16-L18
when probably we should be in this branch:
https://github.com/actions/toolkit/blob/e7eb2c741847a05686a1b8df93dea4b244640b17/packages/cache/src/internal/tar.ts#L20
or use the GNU tar but not MSYS's one.

cc @MSP-Greg

[eregon]

One possible solution would be to save/restore the PATH around saving the cache, but it seems rather inconvenient.

[MSP-Greg]

As you can see, there are a few utilities that exist both in 'Windows' and in MSYS2. I know they're trying to sort it out in the 'virtual-environments' repo, have to go look. I wish they'd hard coded the paths when that happens so the correct tool is chosen, rather then depending on Path...

[eregon]

On https://github.com/eregon/setup-ruby/runs/1392737782?check_suite_focus=true#step:3:100 we can see the cache paths written to manifest.txt is ["vendor\\bundle"] but it should most likely uses / as separator for GNU tar.

[MSP-Greg]

Sorry, I forgot to mention the backslashes. Almost all the MSFT programs/commands one would use in a shell (PowerShell or cmd) accept forward slashes...

[eregon]

I filed an issue upstream: actions/toolkit#632

[eregon]

Fixed upstream, and dependency updated, it works now in https://github.com/ruby/setup-ruby/releases/tag/v1.59.1