[oe] Hash based SCMs and OpenEmbedded/Bitbake

[Holger Freyther]

On Thursday 04 September 2008 13:43:23 Phil Blundell wrote:
> On Wed, 2008-09-03 at 15:54 +0200, Holger Freyther wrote:
> > we have a couple of issues with hash based SCMs (like git) and how we
> > handle them.
>
> It's kind of tempting to say that you should just lean on your upstream
> to make proper releases and use them, rather than trying to pull some
> random bag of bits out of the SCM repository.  However, I guess this was
> not the sort of advice you were looking for. :-}
>
> Perhaps more constructively, my preference would be to use "git log" or
> some such to extract the datestamp of the revision in question, and then
> glue it into PV to make a version string that was sortable and hence
> upgradeable.  So, if you had git revision
> 5a5346dfbec459c10d9e61e16e125b83975a1ef1 or whatever, you'd end up with
> PV = "1.0.0+git20080904T123500
> +5a5346dfbec459c10d9e61e16e125b83975a1ef1".  Obviously you still have
> the possibility of losing if you want to upgrade from one revision to
> another one committed in the same second, but I imagine this does not
> arise often in practice.

What is happening is you cherry-pick from another branch and then you have an 
older revision (by commit date) on top and would be able to upgrade. Nice 
idea but I think it will not work. There is the author/comitter separation 
but AFAIK no for the commit date.


z.