[gentoo-dev] Re: [gentoo-commits] gentoo-x86 commit in games-board/gnugo: gnugo-3.9.1-r1.ebuild ChangeLog

[Michael Palimaka]

On 02/06/15 21:38, Mike Frysinger wrote:
> On 02 Jun 2015 20:47, Michael Palimaka wrote:
>> On 02/06/15 17:04, Michał Górny wrote:
>>> Dnia 2015-06-02, o godz. 03:58:35
>>> "Michael Sterrett (mr_bones_)" <mr_bones_@g.o> napisał(a):
>>>> -DEPEND="readline? ( sys-libs/readline )
>>>> +DEPEND="readline? ( sys-libs/readline:0 )
>>>
>>> This should be actually := (or :0=) for both deps since gnugo links to
>>> them. This also applies to your remaining 'warning silencing' commits.
>>
>> Why? Blindly adding the subslot dep is a bad idea.
>
> in this particular case, the subslot usage is what we want since we're
> compiling+linking against it.  using readline:0 vs readline is still an
> improvement though.
>
> we also want a subslot on ncurses since we compile+link against it.
>
> i think it's pretty uncommon to use readline in a package and not want a
> subslot.  your package would have to be doing something uncommon like
> dlopening it since the only thing readline provides is a library ...
> -mike
>

Neither readline nor ncurses define an explicit subslot, so I don't know
what their future meaning might be.

While this is not likely to ever present a problem for ncurses or
readline, the trend of blindly adding := to all dependencies without
knowing what it actually means is concerning. It would be nice to have
some information first, for example:

* readline subslot will be bumped when libreadline breaks, most packages
want the operator
* poppler has some libraries with stable interfaces, only use the
operator if you link against unstable libpoppler (not libpoppler-qt4)
* libfoo has an additional private, unstable api used only by specific
packages - don't use the operator unless you know what you're doing