Re: [PATCH] tag: support --sort=version

[Jeff King <peff@peff.net>]

On Wed, Feb 19, 2014 at 08:39:27PM +0700, Nguyễn Thái Ngọc Duy wrote:

> --sort=version sorts tags as versions. GNU extension's strverscmp is
> used and no real compat implementation is provided so this is Linux only.

Sounds like a good goal.

I wonder, if we were to merge the for-each-ref and tag
implementations[1], how this would integrate with for-each-ref's
sorting. It can sort on arbitrary fields like "--sort=-*authordate". I
think given the syntax you provide, this would fall out naturally as
just another key (albeit a slightly magical one, as it is building on
the %(refname:short) field but using a different comparator).

Would we ever want to version-sort any other field? Perhaps
%(content:subject) for a tag? I'm not sure what would be the most
natural way to specify that. Maybe "--sort=version:content:subject",
with just "--version" as a synonym for "version:refname:short".

We don't need to do any of that immediately.  This is mostly just me
thinking aloud, to make sure we do not paint ourselves into a corner
compatibility-wise.

-Peff

[1] I have patches which I really need to polish and send out that
    combine the ref-selection code (so tag, branch, and for-each-ref all
    know "--merged", "--contains", etc). I'd really like to combine the
    sorting and formatting code, too, so everybody can use "--sort" and
    "--format" with all of the associated fields.