[Bug 51869] New: ReplaceFileW/A does not work with Unix-style paths

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=51869

Bug ID: 51869
           Summary: ReplaceFileW/A does not work with Unix-style paths
           Product: Wine
           Version: 6.0.1
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: kernel32
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 70784
  --> https://bugs.winehq.org/attachment.cgi?id=70784
Test log

It seems ReplaceFile function does not handle Unix-style paths correctly. I
tested calls like:

ReplaceFileW(L"abc/def/12.txt", L"abc/def/34.txt", NULL, 0, NULL, NULL));
ReplaceFileW(L"abc\def\56.txt", L"abc\def\78.txt", NULL, 0, NULL, NULL));

Under Wine, first call fails, second one succeeds. The relevant part of
WINEDEBUG=+all log is in the attachment. On Windows, both calls succeed.

I attempted to look at Wine code, and it seems the problem is that ReplaceFileW
implementation tries to get directory name of replaced file using
PathRemoveFileSpecW, which only handles backslashes. On Windows,
PathRemoveFileSpecW also works with backslashes only, but ReplaceFileW still
works correctly with Unix-style paths.

For context, I am trying to run a proprietary compiler toolchain under Wine,
and my script passes Unix-style paths to it, which is I believe a common
practice for cross-platform build scripts. The same script works fine on
Windows, but fails under Wine.

I mostly use Wine stable (6.0.1), but tested that Wine 6.19 has the same
behavior.