I installed Plasma 5.9 beta on a stable system with Qt 5.6, but at some point the build failed because of a missing header file in Qt. I then upgraded to Qt 5.7 and were able to finish the emerge. I am sorry I cannot provide the details right now, I forgot to keep the build logs. I will repeat it on a second machine, then I will report back. I assume it should be possible to use Plasma 5.9 together with Qt 5.6 and this is a bug? Otherwise the dependencies need be adjusted.
Thanks. https://gitweb.gentoo.org/proj/kde.git/commit/?id=758e10fc630ff4222a9b6c33b985b7fc783f4500
Created attachment 460016 [details] build.log Thanks! For the sake of completeness, I attach the log of building against Qt 5.6. The first failing package is kde-plasma/plasma-integration-5.8.95 The specific error is /tmp/portage/kde-plasma/plasma-integration-5.8.95/work/plasma-integration-5.8.95/src/platformtheme/qdbusmenubar_p.h:63:65: fatal error: QtPlatformSupport/private/qdbusmenuregistrarproxy_p.h: No such file or directory
Plasma 5.9 compiles just fine with Qt 5.6 and is also supported by upstream (official requirement is >=5.5 actually). This build failure was just some random bug in the beta release as OP assumed initially. Please revert the commit.
What about bug 608342? It is obvious that upstream is not really testing Plasma-5.9 with pre-Qt-5.7 at this point.
Here is an official upstream response about the minimum Qt version - https://bugs.kde.org/show_bug.cgi?id=376199#c2
We probably won't lower QT_MINIMAL for Plasma-5.9 anymore.
