normalise should eliminate parent directories on Windows

[Rufflewind]

Windows seems to interpret paths differently than on POSIX systems.

• On POSIX, /sym/link/../foo refers to /target/dir/../foo ≡ /target/foo (.. expands after dereferencing).
• On Windows, C:\sym\link\..\foo always refers to C:\sym\foo (.. expands before dereferencing).

This feature would be useful to have because if you want to pass in extended-length paths (the \\?\ prefix) you have to normalize the path before adding the prefix, otherwise the Windows API will interpret .. literally.

[ndmitchell]

What if you do the Windows style path on a Mingw shell - does it expand before or after dereferencing?

[Rufflewind]

Tried it in the MSYS shell (that one that comes with Stack):

• C:\sym\link\..\foo expands before deref.
• C:/sym/link/../foo expands before deref.
• /c/sym/link/../foo expands after deref.

[ndmitchell]

That's disturbingly inconsistent... I guess you need two separate methods, one which expands .. and one which doesn't.

[hasufell]

@Rufflewind is this observed behavior or is there something in windows documentation suggesting this is behavior that can be relied upon?

[Rufflewind]

I have not seen documentation around it but I haven't really tried looking per se. It's just a quirk I observed when trying to test native symbolic links on Windows.