KDE Frameworks 5 and Plasma 2 co-installability

It should be possible to install a kde frameworks 5 runtime alonside a kdelibs 4 runtime so apps can use either one

Many paths have changed by default so there is no clash

kdelibs 4 CONFIG_INSTALL_DIR: /usr/share/config
kf5 CONFIG_INSTALL_DIR: /etc/xdg
kdelibs 4 DATA_INSTALL_DIR: /usr/share/apps
kf5 DATA_INSTALL_DIR: /usr/share

HTML_INSTALL_DIR does clash as /usr/share/doc/HTML to allow khelpcentre to find docs from both kdelibs4 land and kf5 land

Plasma Next coinstallability page

kactivities

The libraries are co-installable, but the daemon is not.

libkactivities/qt5 requires kactivitymanagerd/qt5
libkactivities/qt4 works with both kactivitymanagerd/qt4 and kactivitymanagerd/qt5 (though, the later is advised since it is more stable)

In order to build only the library part of kactivities/qt4, you can pass -DKACTIVITIES_LIBRARY_ONLY=true to cmake. libkactivities/qt4 works with the qt5 version of the daemon.

link to the original discussion: https://git.reviewboard.kde.org/r/115602/