Re: [gentoo-dev] [GLEP56] USE flag descriptions in metadata

[Marius Mauch]

On Thu, 05 Jun 2008 17:01:00 -0400
Doug Goldstein <cardoe@g.o> wrote:

> Marius Mauch wrote:
> > On Thu, 05 Jun 2008 15:42:24 -0400
> > Doug Goldstein <cardoe@g.o> wrote:
> >
> >
> >> All,
> >>
> >> Here's a GLEP for the addition of USE flag descriptions to package
> >> metadata. It does not address any future ideas that others may have
> >> had or suggested. It merely gives developers the necessary "tools"
> >> to document their USE flag usage it better detail on a per package
> >> basis.
> >>
> >> An clearly motivation explanation that I didn't add, which I'm
> >> going to add once I send this is the fact that as per the QA
> >> Project, use.local.desc can not contain a USE flag that already
> >> appears globally in use.desc. This would allow a description for
> >> that USE flag to be contained in the metadata.
> >>
> >> http://www.gentoo.org/proj/en/glep/glep-0056.html
> >>
> >> I encourage any and all _technical_ feedback.
> >>
> >
> > Doesn't include any statement about compability with existing tools
> > or how it's related to use.local.desc (replacement, extension, ...)
> >
> > Marius
> >
> It purposefully does not. XML is an extensible language that allows
> for this type of expandability. Current tools should be able to
> validate that adding these tags are valid if they appear in the DTD.
> However, if those tools do not handle those tags they should not do
> anything with them, hence the nature of XML.

I was more talking about tools that process use flag information
(equery, euse, ufed, ...).

> The replacement of use.local.desc would necessitate a change to any
> and all tools which use that file and require them to support the new
> XML data. This of course introduces a chicken/egg issue. I have
> mentioned to infra the possibility of having a pre-rsync process that
> condensed all metadata.xml's into a use.local.desc that would be part
> of rsync data but not part of CVS. This could be written as a CVS
> hook to see when a metadata.xml was touched and run the utility
> appropriately.
>
> But again, this is outside the scope of this GLEP, whose purpose
> merely is to provide a way to document this.

I disagree. At the very least state that the GLEP does not replace
use.local.desc if that's the intention, and which location is
supposed to take priority if a flag is defined in both. Otherwise
different tools will use different rules and generating inconsistent
results. And there are many tools affected by this ...

Marius

PS: I like the general idea, but as long as compability issues are
completely ignored by the GLEP I have to oppose it.
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