[Bug 58188] New: CreateProcessW fails for executables with a dot in their name

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=58188

Bug ID: 58188
           Summary: CreateProcessW fails for executables with a dot in
                    their name
           Product: Wine
           Version: 10.6
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: kernel32
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 78491
  --> http://bugs.winehq.org/attachment.cgi?id=78491
Archive with relevant logs, reproduction program and a proposed patch

If an exe file has a name that contains a dot that's not part of the extension
(e.g. SomeProgram.Component.exe), then call to CreateProcessW using only
lpCommandLine (lpApplicationName = NULL) with the extension of the executable
omitted (SomeProgram.Component arguments) will fail on wine, but succeed on
Windows.

This was observed in wine compiled from source (10.6) and packaged in Ubuntu
24.04 (9.0).

The issue was originally thought to be caused by SearchPathW, but further
investigation showed that this function behaves as it should. There just simply
seems to be a special case or different logic in CreateProcessW that isn't
captured in wine.

Reproduction:
Attached are two C programs used to investigate and reproduce the issue. They
test behavior of CreateProcessW and SearchPathW. Both .c files are meant to be
compiled and placed in the same folder in the following way:
 - BugTest.exe (BugTest.c)
 - SomeApp.exe (SomeApp.c)
 - SomeApp.Component.exe (SomeApp.c)
Afterwards, BugTest.exe is run in the same folder.
Attached are the outputs of running that program in Windows and wine
(output_wine.txt, output_windows.txt). The obvious difference is the failure
whe calling CreateProcessW for SomeApp.Component .

Proposed patch:
Attached is a patch with proposed fix for the above mentioned issue. There is
also on output of BugTest.exe on wine compiled with the attached patch
(output_wine_with_patch.txt), which is the same as what's produced on Windows.

PS: I just noticed that there can only be one attachment. I have packed all the
mentioned files into a zip archive. If that is undesirable I will upload the
files separately.