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

In addition, under Windows, the file names of the executables provided by the framework must differ from those of the KDE4 counterpart, as the 'libexecdir' directory is mapped to the 'bin' directory.

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/