[MU4 Issue] Backslash in paths (CLI) on Windows not working

[geniot]

Describe the bug Backslash in paths causes MuseScore 4 to ignore the command on Windows 10 (CLI).

To Reproduce Steps to reproduce the behavior: Using command line try to export a score on Windows:

The following is ignored silently (no file created): C:/Users/vital/CLionProjects/MuseScore/builds/Win-Qt5.15.2-msvc2019_64-VS16-Release/install/bin/MuseScore4.exe --trim-image 0 --force -o C:\Users\vital\AppData\Local\Temp\166004490466617445266007645084517\score_wide.svg C:\Users\vital\AppData\Local\Temp\166004490466617445266007645084517\score_wide.mscx

The following works: C:/Users/vital/CLionProjects/MuseScore/builds/Win-Qt5.15.2-msvc2019_64-VS16-Release/install/bin/MuseScore4.exe --trim-image 0 --force -o C:/Users/vital/AppData/Local/Temp/166004490466617445266007645084517/score_wide.svg C:/Users/vital/AppData/Local/Temp/166004490466617445266007645084517/score_wide.mscx

Expected behavior Backslash in paths should work the same way as forward slash.

Platform information

• OS: Windows 10.

Additional context This is regression as compared to 3.6.2

[HemantAntony]

Let me guess, the backslash represents escape sequences

[Tantacrul]

@cbjeukendrup - when you have a moment can you comment on priority / severity?

[cbjeukendrup]

Because few users would use MuseScore from the command line on Windows, this specific issue won't have a very big impact. However, I suspect it is related to #12728, which is a P0 and rightfully so.

[DmitryArefiev]

Should be fixed in #12923