Duncan posted on Sat, 26 Jul 2014 08:05:32 +0000 as excerpted:
> Ian Stakenvicius posted on Fri, 25 Jul 2014 14:49:44 -0400 as excerpted:
>
>> Hey all.. So, putting aside for now how much of a mess this would be
>> to implement in the virtuals' ebuilds themselves, what do people think
>> of changing the virtuals so that they contain an entry in IUSE for each
>> provider that can satisfy it?
>>
>> The idea here is that the package satisfying a virtual could be
>> optionally explicitly-chosen through package.use (or USE= in make.conf,
>> perhaps) instead of having an entry in @world, that way if nothing
>> depends on the virtual then it and the provider can be - --depclean'ed
>> from the system. The idea is specifically NOT to have rdeps depend on
>> these flags, that would undermine the whole purpose of the virtual; it
>> would just be for end-users to set if they so chose.
>
> What about handling each such virtual_USE as a USE_EXPAND?
> [Example] VIRTUAL_KRB5
Hmm, thinking toward implementation, what about a virtual.eclass,
inherited by virtuals?
It could even have a declarative interface, such that from
virtual/krb5-0.ebuild (I've left out the minversion and multilib-usedep
stuff here as the example above did as well, but it could be passed
too)...
inherit virtual
VIRTUAL_EXCLUSIVE="app-crypt/mit-krb5 app-crypt/heimdal"
... would setup most of the basics for an exclusive virtual, including
the VIRTUAL_KRB5 USE_EXPAND name (based on $PN), the two providers and
rdepends, the fact that they're exclusive and thus a default pkg_pretend
or required_use, etc.
In for instance virtual/editors, this could be used in place of its
current RDEPEND:
VIRTUAL_MULTI="
app-editors/nano
app-editors/dav
app-editors/e3
...
mail-client/alpine[-onlyalpine]
sys-apps/ed
"
With an eclass, the default pkg_pretend for exclusive-virtuals would be
standardized, standardizing the error message and explanation for it as
well, giving it a chance to be a bit more informative than unstandardized
one-offs might tend to be.
Of course the same eclass idea could be used with simple USE flags as
well, but I prefer the USE_EXPANDs.
--
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
