[oe] Why PREFERRED_VERSION setting of <distro>.conf overrules local.conf setting ?

[Mike Westerhof]

Frans Meulenbroeks wrote:
> 2010/8/10 Graham Gower <graham.gower at gmail.com>:
>> On 10 August 2010 04:31, Frans Meulenbroeks <fransmeulenbroeks at gmail.com> wrote:
>>> 2010/8/9 Chris Larson <clarson at kergoth.com>:
>>>> On Mon, Aug 9, 2010 at 6:26 AM, Hauser, Wolfgang (external) <
>>>> Wolfgang.Hauser.external at eads.com> wrote:
> 
>>>> PREFERRED_VERSION_<package>_local = "xxx" is how you use the override.
>>> The real solution woud be to either temporary store the
>>> PREFERRED_VERSION and apply it later on.
>>> Alternately we could parse local.conf twice, the first time ignoring
>>> the PREFERRED lines, and the 2nd time only looking at these.
>>> Yet another solution could be to split local.conf into two pieces, one
>>> with settings like MACHINE and DISTRO, the other one with the
>>> overrides.
>> Wouldn't it be far simpler to fix the distro conf file(s)? E.g. apply
>> something like this:
>> s/^PREFERRED_VERSION_\([a-z]*\) =/PREFERRED_VERSION_\1 ?=/
> 
> Yeah.
> Didn't really think about that one, but if distro's want to change and
> adhere to it, that would be the simplest solution
> Machines that pin something should probably also use weak binding.
> Conceptually it is probably marginally less desirable than a solution
> where local.conf has *always* control.
> 
> What do the distro's think about this?

I think it is the decision of EACH DISTRO to make, and not something to
be dictated by OE in general.

Mind you, I appreciate the general recommendation -- it's a sound idea
to make it so that a knowledgeable developer's local.conf overrides most
distro preferred version settings.  I use the technique frequently.

But on the other hand, I appreciate the ability to lock down some
preferred versions where I feel that it simply doesn't make sense to let
local.conf override.  For example, there's usually a LOT more to
changing the kernel version for SlugOS than just setting
PREFERRED_VERSION.  By the time a developer has figured out OE well
enough so they can find the distro conf files and understand how they
work, then I expect they also understand what extra stuff they need to
do for the kernel as well.  (Not to mention that I could - and should -
add some comments in the distro conf file to explain how that all works,
which is something I can't do in a generic local.conf file quite so well.)

It's a trivial point; if the community wants to begin to dictate such
little nuances to distros, it's not important enough to me to argue.
But you asked what the distros think, so I answered. :)

-Mike (mwester)