Re: Version numbers for VCS snapshots

[Leo Famulari <leo@famulari.name>]

On Thu, Jan 21, 2016 at 02:51:29PM +1000, Ben Woodcroft wrote:
> 
> 
> On 12/01/16 19:26, Ludovic Courtès wrote:
> >Ricardo Wurmus <rekado@elephly.net> skribis:
> >
> >>Should we also take some time to reconsider how we name unreleased
> >>versions like arbitrary git commits?
> >Let do that!
> Lets.
> >>So far we have been picking the latest release version (or “0.0.0” if
> >>there hasn’t been any release) followed by “.” and either a date or a
> >>guix-internal revision number, then again a “.” followed by part of the
> >>commit hash.
> >>
> >>I’m afraid that we might accidentally introduce conflicts with future
> >>release versions, e.g. when the latest release only uses two digits
> >>(e.g. “0.1”) and we add a revision or a date (e.g. “0.1.1” or
> >>“0.1.20160112”) and the next release and the next official release
> >>switches to three digits (e.g. “0.1.1”).
> >>
> >>Would it make sense to separate our version identifier from the actual
> >>release version with a different character than “.”?  Or should this be
> >>discussed elsewhere as it hasn’t anything to do with how we specify
> >>versions on the command line?
> >Probably.  Debian, for instance, uses “2.0.11-9” where “9” denotes the
> >9th package revision of upstream version “2.0.11”.  We could probably
> >use that convention.
> >
> >In a previous discussion on this topic, I suggested that we should have
> >such a revision number instead of just “x.y.COMMIT”.  The extra
> >monotonically-increasing revision number is needed to allow upgrades to
> >work as expected.
> >
> >So, a Git snapshot’s version number could be:
> >
> >   2.0.11-3.deadbeef
> >     ^    ^    ^
> >     |    |    `— upstream commit ID
> >     |    |
> >     |    `—— 3rd Guix package revision
> >     |
> >   latest upstream version
> >
> >The next snapshot would be:
> >
> >   2.0.11-4.cafeefac
> >
> >WDYT?
> I can't see anything wrong with this myself. Is this accepted policy now?
> 
> Also, is the convention for unreleased software to take 0.0.0 as the version
> as you suggest Ricardo e.g. 0.0.0-1.deadbeef ?

That sounds good to me. There was some discussion of how much of the
hash to keep here:
http://lists.gnu.org/archive/html/guix-devel/2015-12/msg00136.html

I like this method that I've seen in some of the packages, because it
keeps the version tidy while preserving the full hash:

--8<---------------cut here---------------start------------->8---
(define-public hello
  (let ((commit "e8e46123cfe62170a2f7f79db6b471b66ae36947"))
    (package
      (name "hello")
      (version (string-append "2.10-1" (string-take commit 8)))
      (source (origin
                (method git-fetch)
                (uri (git-reference
                       (url "git://git.sv.gnu.org/hello.git")
                       (commit commit)))
                (sha256
                [...]
--8<---------------cut here---------------end--------------->8---

> 
> ta
> ben
>