On Tue, Oct 02, 2012 at 02:08:02PM -0400, Ian Stakenvicius wrote:
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> On 02/10/12 01:56 PM, Ciaran McCreesh wrote:
> > On Tue, 02 Oct 2012 13:51:01 -0400 Ian Stakenvicius
> > <[email protected]> wrote:
> >> On 30/09/12 05:53 PM, Ciaran McCreesh wrote:
> >>> On Sun, 30 Sep 2012 14:42:14 -0700 Brian Harring 
> >>> <[email protected]> wrote:
> >>>>> The second is that it starts the conceptual shift from
> >>>>> "cat/pkg is a build dep, and cat/pkg is a run dep" to
> >>>>> "cat/pkg is a dep that is required for build and run".
> >>>> 
> >>>> Fairly weak argument at best; you're claiming that via
> >>>> labels, "contextually they know it's these deps" in
> >>>> comparison to via dep:build "contextually they know it's
> >>>> exposed only in build".
> >>>> 
> >>>> Same difference.
> >>> 
> >>> It's rather a big deal now that we have := dependencies.
> >>> 
> > 
> >> So you would using your labels syntax, specify an atom with a :=
> >> dep using certain labels and the same atom without ':=' on other
> >> labels? I don't quite follow what you're getting at here as to
> >> how this is a big deal..
> > 
> > A := only makes sense for a dependency that is present both at
> > build time and at runtime. Currently, the only place you should be
> > seeing a := is on a spec that is listed in both DEPEND and
> > RDEPEND.
> > 
> > Conceptually, the := applies to "the spec that is in both DEPEND
> > and RDEPEND". But with the current syntax, there's no such thing as
> > "the spec that is in both". There are two specs, which happen to
> > be identical as strings, one in DEPEND and one in RDEPEND, and
> > there's no way for the two to be associated.
> > 
> 
> Current syntax = *DEPEND, yes.  Completely agree.
> 
> In relation to Brian's proposal for DEPENDENCIES, tho, the two specs
> which happen to be identical strings would be rolled out from the same
> - -actual- string in the ebuild, and so, I don't see any such 'big deal'
> between the ability to conceptually express what's going on via his
> syntax and your labels.
> 
> Unless i'm missing something, 'same difference' still fits..

Same difference applies; he's making the claim that the resolver can't 
tell that the python atom should be the same between build/run:

dep:build,run? ( dev-lang/python:2.7= )
build: dev-python/snakeoil

# vs labels

build+run: dev-lang/python:2.7=
build: dev-python/snakeoil

The argument there is basically predicated on the belief that only 
labels can 'color' the sections it contains.  This is a bullshit 
claim, and possibly specific to paludis internal failings.

A sane implementation can walk that parse tree, and minimally infer 
that on it's own via the walk- or if it's saner, just track where 
things came from, and sort it via that way.  Realistically a *good* 
implementation would likely be doing a partial rendering anyways (a 
good implementation already has the machinery for this for QA analysis 
reasons)- meaning conditionals beyond dep: would be finalized, leaving 
just those nodes unrendered, and then doing quick pass rendering of 
that intermediate form to get each phases specific requirements.

Honestly it's a bullshit argument anyways; the unstated, but core 
argument of such nonsense is that the resolver if it saw

dep:build? ( dev-lang/python:2.7= )
dep:run? ( dev-lang/python:2.7= )

would, because it's not one single build/run construct, think it can 
vary python:2.7  Any/all sane resolver already do collapsing and 
stabilization of common nodes across dep phases (and if paludis 
doesn't, well, that's their mess to sort; we're not getting any 
PROPERTIES=funky-slots hacks to work around their brain dead 
breakage here).

The same situation can occur w/ labels via eclass dep manipulation; 
this is an artificial example, but anyone who has done deps know this 
sort of thing can/does occur via eclasses injecting common deps in:

encode? ( build: dev-lang/python:2.7= )
build,run: dev-lang/python:2.7=

Oh noes.  How ever will the resolver know that it shouldn't vary the 
micro version of dev-lang/python:2.7 between build and run in that 
case!  You just *know* it wants to vary the micro version because, 
such a completely fucking worthless thing for the resolver, it must do 
because it can, right?

Etc.  It's a pure bullshit argument, potentially derived from 
implementation issues for his own code, or just academic wankery; 
unsure of which, don't care which since the core argument is a 
new level of cracked out.

~harring

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