Re: [gentoo-dev] RFC: GTK USE flag situation (gtk, gtk2, gtk3; relevant to bug #420493)

[Chris Reffett]

On 2/12/2014 3:09 AM, Michał Górny wrote:
> Dnia 2014-02-11, o godz. 19:33:06 Chris Reffett
> <creffett@g.o> napisał(a):
>
>> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
>>
>> On 02/11/2014 06:13 PM, Gilles Dartiguelongue wrote:
>>>> Unfortunately, the concurrent nature of gtk2/gtk3 has
>>>> resulted in packages that may support either or both the
>>>> toolkits. To handle this, a few developers have introduced
>>>> the "gtk3" useflag, that prefers gtk3 over gtk2 when both
>>>> toolkit versions are supported. At this point, the Gnome
>>>> team highly recommends prefering gtk3 if possible, skipping
>>>> the useflag altogether. [1]
>>>
>>> Wrong, as is written in policy whether to prefer gtk2 or 3 is
>>> up to the maintainer of the package. We point people to the
>>> fact that upstream says gtk2 is a dead end and support will
>>> stop (if not in fact already stopped) in the near future.
>>>
>>> We also recommend to have maintainers support slots for their
>>> libs where possible considering man-power and to only choose
>>> one toolkit for applications considering where upstream
>>> development is going and maturity of the port, and again, this
>>> is up to package maintainers.
>> This doesn't make sense to me at all. I can't see why slotted
>> libraries can't just use USE flags to specify what toolkit
>> they're built against, just like any other package in the tree
>> (so, for example, a package that needs webkit-gtk built against
>> gtk3 would depend on webkit-gtk[gtk3] instead of webkit-gtk:3).
>> I'm well aware that there could be limitations I'm unaware of
>> (maybe the package only can build one at a time?), but this is
>> how it looks to me. By switching to versioned gtk flags, this
>> kills two birds with one stone: it makes it obvious to the end
>> user which version they're trying to build their package
>> against, and it gets rid of the need for (ab)using revision
>> numbers to implement slots like that.
>
> Except when you end up rebuilding the huge thing twice. Or trying
> to live with binpackages -- the thing that most Gentoo developers
> don't care about at all. They just love their precious USE flags
> so much they'd shove them everywhere for the sake of it.
>

You'll have to build it twice anyway, this just splits it into two
separate packages, and I suspect that the times where you will have to
rebuild are when a package needs webkit-gtk to support another toolkit
(which should happen only once), and when you upgrade (in which case
you would be updating them separately anyway). I also fail to see what
this has to do with binpkgs: if something needs webkit-gtk[gtk2], you
add a dep on webkit-gtk[gtk2]. The user adds USE=gtk2 to webkit-gtk if
needed, webkit-gtk binpkg gets rebuilt. I see no breakage there.

Chris Reffett