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

[Khem Raj]

On Tue, Aug 10, 2010 at 1:56 PM, Chris Larson <clarson at kergoth.com> wrote:
> On Tue, Aug 10, 2010 at 1:50 PM, Koen Kooi <k.kooi at student.utwente.nl>wrote:
>
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>> On 10-08-10 01:15, Graham Gower wrote:
>> > 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:
>> >>>
>> >>>> Hello,
>> >>>>
>> >>>> I want to change some used versions of packages, so I added a
>> >>>> PREFERRED_VERSION_<package>="xxx" for the packages I want to have a
>> >>>> special(newer) version to be used.
>> >>>>
>> >>>> But e. g. for busybox the version defined in the used <distro>.conf is
>> >>>> used instead of my setting in local.conf.
>> >>>>
>> >>>> Should local.conf not overrule <distro/machine>.conf ??
>> >>>
>> >>>
>> >>> Conceptually, local should override everything, as it's the "most
>> specific"
>> >>> information available, but from a technical standpoint, we can't parse
>> the
>> >>> machine and distro configs until local.conf is parsed, as that's
>> usually
>> >>> where the MACHINE and DISTRO are set.  You can use a 'local' override
>> to get
>> >>> around it, or you can ask the distro/machine maintainer to use ?=
>> >>> assignments (set only if unset).
>> >>>
>> >>> 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 ?=/
>>
>> What's the point of setting a preferred version at all if you make it a
>> weak assignment?
>> The distro nearly always knows better and if you want to use a different
>> version, sending a patch to change that version for review isn't exactly
>> rocket science.
>
>
> How about having decent usability?  The user asking for something and not
> getting it is completely unintuitive.  If the user doesn't know what they
> want, they won't request a specific version.  If they do request it, they
> should get it, anything else is an OE usability issue.

why not use _local override and I think if user want to alter
a distro choice I consider that user to be not a beginner.

> --
> Christopher Larson
> clarson at kergoth dot com
> Founder - BitBake, OpenEmbedded, OpenZaurus
> Maintainer - Tslib
> Senior Software Engineer, Mentor Graphics
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