KDirListerCache destroy comment in kcoredirlister.cpp

[René J.V. Bertin]

Hi,

Researching an issue I'm seeing (hang/crash on exit) I found the following vestigial out-commented code the KCoreDirListerCache ctor in kcoredirlister.cpp:

    // Probably not needed in KF5 anymore:
    // The use of KUrl::url() in ~DirItem (sendSignal) crashes if the static for QRegExpEngine got deleted already,
    // so we need to destroy the KCoreDirListerCache before that.
    //qAddPostRoutine(kDirListerCache.destroy);

WHat's clear is that this no longer works: there is no `destroy` method in whatever kDirListerCache's real class is.

Git blame is of little help here; can anyone remember why the explicit pro-active delete was deemed unnecessary, and what the exact symptoms were when this was not done in KDE4?

FWIW, the crash (or hang) happens during QRegExpEngine take-down when I have used a KDE file dialog in a "pure Qt" application via a mechanism built on code taken from the plasma integration plugin. It does not happen in KF5 applications like kate or kdialog. As far as I know those applications obtain the KDE file dialog from the platform plugin too. The difference must be in the order in which certain things are deleted during the global destruction phase, but which and how to restore the proper order.
(The Audacious audioplayer had a similar issue on exit in its Qt5 version, which I traced to the QApplication instance being deleted via atexit; a lucky shot in the dark that makes a lot of sense in retrospect.)

Thanks for any pointers,
R.