[gentoo-dev] Re: Fwd: Heads up for Qt5

[Duncan]

Nikos Chantziaras posted on Sat, 28 Jul 2012 13:07:08 +0300 as excerpted:

> On 28/07/12 12:27, Ralph Sennhauser wrote:
>> On Sat, 28 Jul 2012 15:54:07 +0800 Ben de Groot <yngwin@g.o>
>> wrote:
>>
>>> We do not have (nor want to support) a qt useflag. We have opted for
>>> "qt4" and "qt5" useflags as the most straightforward and least
>>> confusing.
>>
>> Indeed, the flag qt has almost disappeared from the tree. Good to know.
>
> Why the different policies between the gtk and qt USE flags?  This just
> looks inconsistent.

Different gentoo projects.  Different people involved with their own 
preferences.  But I believe it's mostly an accident of history.

The gtk/gtk2 evolution went rather poorly as IIRC there really wasn't an 
original defined policy, so the gtk USE flags were ambiguous.  At first 
USE=gtk2 was discouraged for a lot of packages, since for them it meant 
favoring the still (at the time) less stable gtk2 over gtk1.  USE=gtk 
meanwhile, sometimes meant favor gtk1, while at other times it meant let 
the package maintainer pick the best one to support.  Of course that 
caused problems later on, after gtk2 matured and gtk1 was being phased 
out, so a general policy was adopted, that AFAIK remains today: USE=gtk 
meant support gtk in any form, with USE=gtk1/gtk2 (and now gtk3, with 
gtk1 phased out) meant prefer that specific version instead of letting 
the package maintainer choose a default.

But the key point there is that said policy was kind of fallen into by 
accident, and once in place, it was simply more convenient to maintain 
it, then to change it yet again.

When the qt3/qt4 case came along, they had the lessons of the gtk case to 
examine and decided to avoid the problem by switching to specific-
versioned qtX flags I believe before/as qt4 hit the tree.  Of course the 
fact that the existing in-tree support was already qt3 helped, since that 
was already more intuitive than gtk1.  From quite early on, then, simple 
qt was never allowed the ambiguity of gtk -- it always meant qt3 but was 
quickly deprecated in favor of the qt3 flag.

Of course also helping things was the fact that the qt3 ecosystem was 
much more monolithic and kde3 much more dominant within it than was the 
case with either gtk1/gnome1 or the now somewhat broader-ecosystem qt4/
kde4.  So getting buy-in for the quick deprecation of qt in favor of qt3 
was much closer to simply getting by-in from the gentoo/kde folks (with a 
large overlap between them and the gentoo/qt folks), as opposed to the 
wider cooperation needed in the gtk case.

So to a large extent the fact that gtk means any gtk while the versioned 
ones mean prefer that version, while there's ONLY the versioned qtX 
flags, is an accident of history.  And since then, the respective gtk/qt 
policies have remained in place due to inertia -- yes there's an 
inconsistency between them, but users of each quickly get comfortable 
with it, and the cost-benefit ratio of trying to change either one now, 
simply hasn't been considered worth it.  Thus as new versions appear, 
gtk3 and now qt5, they simply follow type.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman