MkdirAll is not respecting opts.FS

[nianyush]

copy/copy.go

Line 104 in e40f4e6

if err = os.MkdirAll(filepath.Dir(dest), os.ModePerm); err != nil {

[nianyush]

probably should use an alterantive MkdirAll that is compatible with fs.FS like https://github.com/twpayne/go-vfs/blob/master/mkdirall.go#L16

[otiai10]

Thank you for your comment. Could you please create a test case that demonstrates the failure you described?

[mafredri]

Not sure if this is the use-case @nianyush was referring to, but I created a PR #162 with some tests that don't work to illustrate the problem.

[nianyush]

yes, i think your pr exactly describes what i was facing earlier @mafredri