Except for KTP all of our kded modules have been ported to JSON (T11919).

This raises the question of whether we want to keep compatibility with possible third-party legacy modules until KF6

We must keep compatibility, yes. That's the promise of KDE Frameworks. There *is* more KF5-based code outside lxr.kde.org.

Not possible at this point as kded uses KSycoca::self().

AFAICS we need "KSycoca::self()->ensureCacheValid()" in kded for the "void Kded::recreate(bool initial)" method.

An alternative might be to call kbuildsycoca6 as a process or load a symbol from a library that that we can run.

Or we could make KService provide a kded module in KService

There's also KSycoca::clearCaches() and KSycoca::self()->allResourceDirs()

That said I think there's no strong need to get rid of KService here, it doesn't really have an effect on the overall KF dependency tree