[Bug 58891] New: Mono's ProcessTest:Start1_FileName_Whitespace test fails

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=58891

Bug ID: 58891
           Summary: Mono's ProcessTest:Start1_FileName_Whitespace test
                    fails
           Product: Wine
           Version: 10.17
          Hardware: x86-64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: kernel32
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

To reproduce, download
https://dl.winehq.org/wine/wine-mono/10.3.0/wine-mono-10.3.0-tests.zip and run:
wine run-tests.exe
MonoTests.System.Diagnostics.ProcessTest:Start1_FileName_Whitespace

This test, and Start2_FileName_Whitespace, recently started failing.

Here is the source code for the test:
https://gitlab.winehq.org/mono/mono/-/blob/main/mcs/class/System/Test/System...

The failing line is: Assert.IsTrue (ex.NativeErrorCode == 2 ||
ex.NativeErrorCode == 5 || ex.NativeErrorCode == 87, "#6");

It seems it calls a CreateProcess function (I don't remember which) with
whitespace and expects to get one of a few specific error codes. There's a
comment indicating Mono is doing this wrong somehow, but since the test passes
in Mono on Windows (according to the comment returns error code of 5, which
doesn't match .NET Framework but is accepted by the test), that still implies a
difference between Wine and Windows somewhere outside of Mono.

Bisect result:
0fcc187de4117901e1c7c45b17e5f101d8bc6fe6 is the first bad commit
commit 0fcc187de4117901e1c7c45b17e5f101d8bc6fe6
Author: Alexandre Julliard 
Date:   Tue Oct 28 17:28:16 2025 +0100

kernelbase: Fix error returned for paths with a trailing backslash.

Based on MR !6759 by Fabian Maurer.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=57376