RFC: split platformtheme plugin from frameworkintegration and move to kde/workspace

[David Faure]

On Thursday 10 December 2015 10:38:06 Weng Xuetian wrote:
>  if you want to achieve the same feature in some
> other desktop, it would be better to make a fork of
> frameworkintegration.

Not frameworkintegration, just the platformtheme (QPT).

Like some others before, you're confusing frameworkintegration
(the framework, which contains 3 different things) and
the platformtheme plugin (which is one of these things).

There is 0 point in anyone forking the other things like
integrationplugin, which is about KMessageBox being able
to use KConfig when both are installed.

---

Back to the topic: the platformtheme plugin is indeed about "KF5 based apps
integrating better with the plasma desktop, visually". I.e. getting
a KFileDialog in Plasma. The thing is, this could be generalized to
"getting a KFileDialog in plasma or any other workspace based on Qt+KF5"

But I don't even know if e.g. LXQt wants to see the KDE File Dialog or the Qt File Dialog.
-> CC'ing Jerome Leclanche for input.

However, as Martin says, the *current* code is only loaded in a plasma
session anyway (Qt looks for e.g. $XDG_CURRENT_DESKTOP=KDE)
so this move won't, in itself, change anything for LXQt users.

Therefore I'm OK with it moving. (*)

I would just like to define the best architecture longer term. If KFileDialog is
wanted outside of plasma, then indeed some code should move back to KF5
(e.g. in KIO) and be shared between the platformthemes. But not the code
that derives from QPA classes since they are not fully public, gah....

(*) 
The packagers are going to hate this though, there will be a conflict between
KF 5.16 and Plasma X.Y (the next release), which will only be resolved once
KF 5.17 is out. Any time we move something we go against the idea
of "separate products".
This is never simple to solve. If you make plasma check for the KF version
at cmake time to skip the installation of the plugin, someone then upgrading
from KF 5.16 to KF 5.17 ends up with no plugin at all.
Changing the filename is one option, I guess the theme factory in Qt will
then randomly pick one of the two plugins providing the key "KDE" ?

-- 
David Faure, faure at kde.org, http://www.davidfaure.fr
Working on KDE Frameworks 5