Re: [gentoo-dev] RFC: splitting virtual/

[Zac Medico]

On 08/17/2011 12:20 AM, Michał Górny wrote:
> On Tue, 16 Aug 2011 03:01:26 -0700
> Zac Medico <zmedico@g.o> wrote:
>
>> On 08/16/2011 02:32 AM, Ciaran McCreesh wrote:
>>> On Tue, 16 Aug 2011 00:19:38 -0700
>>> Zac Medico <zmedico@g.o> wrote:
>>>>> Isn't that another, ugly, non-PMS hack which makes people think
>>>>> they are creating correct packages?
>>>>
>>>> Are you saying that you'd prefer to have package managers pull in
>>>> redundant packages for not good reason?
>>>
>>> No, package managers should get things right regardless of whether
>>> something is in the 'virtual/' category or not. If they can't get
>>> things right, then we need to supply them with more data.
>>
>> Consider the virtual/jre and virtual/jdk case. Suppose that
>> virtual/jdk isn't installed for some reason, but dev-java/sun-jdk
>> which satisfies it is already installed.  In this case, unless you
>> know that virtual/jdk is zero-cost, it's not clear that it costs less
>> to install virtual/jdk than to install dev-java/sun-jre-bin. There
>> may be lots of cases like this where zero-cost metadata would be
>> useful.
>
> Maybe virtual/jre & virtual/jdk should me merged into a single ebuild
> with USE-switchable behavior? Something like:
>
> RDEPEND="jdk? ( || ( a-jdk b-jdk ) )
> 	!jdk? ( || ( a-jre b-jre a-jdk b-jdk ) )"

Here it seems like you're introducing a USE flag in order to overcome a
shortcoming of the dependency resolver.

Note that the jre and jdk relationship isn't necessarily the only
relationship with these properties. Wouldn't it be better to make the
dependency resolver a bit smarter (as implemented in portage for many
years), than to introduce a bunch of workarounds like the jdk USE flag
that you suggest?
-- 
Thanks,
Zac