Re: [RFC] Do postfiles make sense?

[Joshua Lock <josh@linux.intel.com>]

On Fri, 2011-08-12 at 11:01 -0700, Daniel Lazzari wrote:
> >-----Original Message-----
> >Date: Thu, 11 Aug 2011 16:27:34 -0700
> >From: Joshua Lock <josh@linux.intel.com>
> >Subject: [bitbake-devel] [RFC] Do postfiles make sense?
> >To: bitbake-devel@lists.openembedded.org
> >Message-ID: <1313105254.2506.8.camel@vorpal.jf.intel.com>
> >Content-Type: text/plain; charset="UTF-8"
> >
> >All,
> >
> >Some time ago I added an -R switch to bitbake for configuration files to
> >load after bitbake.conf[1].
> >
> >I'd been happily using this for the UI I've been working on without
> >fully realising that it's not safe to rely on postfiles to set variables
> >which affect the files included by bitbake.conf. For oe-core this
> >includes: BUILD_SYS, TARGET_SYS, MACHINE, SDKMACHINE and DISTRO.
> >
> >In light of this flaw do postfiles make sense?
> >
> >For the UI's purpose I think I'm going to have to switch to a prefile
> >(-r) in the wrapper script and add logic to hob to detect whether the
> >set variables differ from those in hob.local.conf - so that we can warn
> >those with a local.conf that uses = assignment that things won't work...
> >
> >Thoughts? Suggestions?
> >
> >Thanks,
> >Joshua
> >
> >1.
> >http://git.openembedded.org/cgit.cgi/bitbake/commit/?id=a8246ae5400c23df
> >0d3ee29c36f4d9f257d1e6d1
> >--
> >Joshua Lock
> >        Yocto Project "Johannes Factotum"
> >        Intel Open Source Technology Centre
> >
> 
> I actually have a decent use case for a postfile. We have several in
> house recipes that use an SVN repo for their SRC_URI. The URI contains
> a variable that points to what branch to build from. So the recipes
> default to pulling the head revision of trunk. It's nice to be able to
> have a collection of different conf files that we can post load to
> override the branch and revision variables without having to change the
> recipes themselves. So we have like a Release1.1.conf file that when
> post loaded builds Release 1.1 from the correct branches and revisions.
> We can do this with -r by using BRANCH ?= "TRUNK" in the recipes
> (that's how we did it in OE Classic), but when we sometimes forgot the
> question mark, it would end up building TRUNK no matter what was in the
> conf file.

Nice, you've convinced me that the feature should stay.

Thanks for responding,

Joshua
-- 
Joshua Lock
        Yocto Project "Johannes factotum"
        Intel Open Source Technology Centre