Pre-merge CI for Gerrit

[Jan Kundrát]

Hi,
I managed to get a pre-merge continuous integration working with Gerrit. 
This means that whenever someone uploads/updates a change to Gerrit, it 
gets through a CI run and the result is reported back to Gerrit as an 
advice -- see e.g. [1] for an example. A KDE developer can still override 
the CI result if they choose so.

For technical reasons, the CI is independent on the KDE's own CI, both 
software wise and in respect to the build HW. It's using very similar 
tooling to what the OpenStack project is doing -- everything iss 
coordinated by Zuul [2] while the actual jobs are launched by Turbo-Hipster 
[3]. Resource-wise, see [4] for where it's running.

Right now, the CI runs only for dummy.git (doing nothing) and for 
trojita.git (doing three separate build & test checks to cover various 
combinations of ancient and new Qt4, Qt5, clang, gcc and debug and release 
builds). Doing this for Trojita was pretty easy because it has no 
dependencies on other projects except Qt. I'm of course all for extending 
this to other KDE projects as well, and help is welcome.

With kind regards,
Jan

[1] https://gerrit.vesnicky.cesnet.cz/r/167
[2] http://ci.openstack.org/zuul/
[3] http://josh.people.rcbops.com/2013/09/building-a-zuul-worker/
[4] https://conf.kde.org/en/Akademy2014/public/events/140

-- 
Trojitá, a fast Qt IMAP e-mail client -- http://trojita.flaska.net/