in desktopexecparser.cpp there's this line:
            result << QStandardPaths::findExecutable("kdesu") << "-u";

which fails to find kdesu because that is installed to prefix/lib/libexec (kdesu is part of kde-cli-tools)

this breaks *all* desktop files with X-KDE-SubstituteUID=true as desktopexecparser is used by klauncher to construct the launch command for kdeinit and since it returns an empty path where kdesu is supposed to go it will try to launch something like "" "-u root /usr/bin/kittens"


Reproducible: Always

Steps to Reproduce:
1. add X-KDE-SubstituteUID=true to any desktop file
2. kbuildsycoca5
3. try to launch the app via plasma/krunner

Actual Results:  
completely useless and bugged out error window

Expected Results:  
kdesu should come up