installing first @kdebase-4.2 and then trying to install @kdebase-4.3 (both with kdeprefix use-flag) does not work because of pykde file colissions. kdeprefix seems to have no impact on pykde. log attached, emerge --info too.
Created attachment 181256 [details] emerge --info
Created attachment 181258 [details] files which collide
Just an idea but perhaps we need to have '+kdeprefix' USE flag only apply between KDE3 and KDE4 versions, and not have multiple slotted KDE4 versions. IE. Installing kde-4.3 when kde-4.2 is already installed would upgrade to kde-4.3 and uninstall kde-4.2.
The other alternative is to simply use '+python' for only one instance of KDE-4.x and '-python' for all other instances of KDE-4.x
kdeprefix also applies for minor versions (everything else installs in /usr/kde/4.2/, /usr/kde/4.3/). so for me it seems the kdeprefix-flag is simply not working for that package. i'll try the suggestion with "-python", but regardless if it works or not the bug should either be fixed or, if prefixing is not possible, the kdeprefix-flag removed and the packages should block each other.
You also get the same file collisions problem from files installed by kde-base/plasma-workspace, but again it's only if '+python' is set. Pykde4 4.2 and 4.3 should block each other outright as I don't believe prefixing is possible for this package, though would love for someone to prove otherwise. Plasma-workspace 4.2 and 4.3 should also block each other but only if '+python' is set otherwise blocking plasma-workspace versions would defeat slotting for minor versions at all.
Bug still present with kde-base/pykde4-4.2.1 and kde-base/pykde4-4.2.68.
This bug has been "fixed" by masking kdeprefix useflag. If you really want to use kdeprefix join us on #gentoo-kde and help us with proper implementation of that feature. Cheers