Re: [gentoo-dev] RFD: EAPI specification in ebuilds

[Rich Freeman <rich0@gentoo.org>]

On Fri, Mar 9, 2012 at 12:47 PM, Zac Medico <zmedico@gentoo.org> wrote:
> Anyway, lets focus on our main goal, which is to decide on a way to
> obtain the EAPI _without_ sourcing the ebuild.

Agreed.  Plus, an approach that either uses the filename or something
like a comment line is also going to be much more flexible if bash
syntax changes substantially, or if we want to support
ebuilds-in-python or some other approach.

That is the main merit I see to the shebang approach - you could
define some kind of API that actually involves executing the ebuild.
Sticking the EAPI in the filename is a little less complicated and it
gives you the same flexibility - I'm not aware of any file format that
is fussy about the content of the filename.

Even approaches like putting EAPI=5 in the file (even inside a
comment) might break if the file is meant to be generally interpreted
by some program that has rigid syntax rules.    Most scripting
languages could probably handle this somehow, but if you ever wanted
ELF ebuilds that wouldn't be so likely to fly unless you could embed
\nEAPI=ELF8\n in something near the start of the file.

Sure, I doubt we'll ever want ELF ebuilds (I'd consider
non-programatic ebuilds for more trivial packages more likely), but
the point is that we should prefer options that offer more flexibility
down the road over ones that solve the immediate need but just leave
us with the same debate two years from now.

Rich