[bitbake-devel] [RFC] Do postfiles make sense?

[Daniel Lazzari]

>-----Original Message-----
>Date: Thu, 11 Aug 2011 16:27:34 -0700
>From: Joshua Lock <josh at linux.intel.com>
>Subject: [bitbake-devel] [RFC] Do postfiles make sense?
>To: bitbake-devel at lists.openembedded.org
>Message-ID: <1313105254.2506.8.camel at 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.