os: Remove empty directory fails with "process cannot access the file because it is being used by another process" on <= Windows 10

[bep]

I don't have a simple test case for you, but some data points:

• This is a new issue in Go 1.20. It's working OK in Go 1.19.
• It's been reported failing on Windows 8 and 10. It always fail for me on my Windows 8 VM.
• It's not failing on Windows 11.

The failing code is more or less the snippet below:

_, err = f.Readdirnames(1)
if err == io.EOF {
   // Empty dir.
   err = os.Remove(dirname)
  // Gets "process cannot access the file because it is being used by another process" on Windows <= 10.
}

And dirname has recently been used (but not anymore).

gohugoio/hugo#10781

[bep]

OK, turns out I had the directory in question open, which now fails on Windows. I guess that's sensible. Closing.