[yocto] Undefining a variable in a recipe?

[Alex J Lennon]

On 02/05/2014 14:07, Otavio Salvador wrote:
> On Fri, May 2, 2014 at 10:01 AM, Alex J Lennon
> <ajlennon at dynamicdevices.co.uk> wrote:
>> On 02/05/2014 13:56, Otavio Salvador wrote:
>>> On Fri, May 2, 2014 at 2:24 AM, Alex J Lennon
>>> <ajlennon at dynamicdevices.co.uk> wrote:
>>> ...
>>>> So I guess I'm at the point where I'm wondering if a getVar() with a
>>>> flag is behaving as you would expect it to,
>>>> or how I might go about ensuring either UBOOT_MACHINE or UBOOT_CONFIG
>>>> isn't defined?
>>>>
>>>> Thanks in advance for any advice,
>>> I think we have a simple error error. You are mixing a recipe, which
>>> is old and a metadata layer with new concepts.
>>>
>>> The u-boot-imx, in 2009.08 recipe, used to set the UBOOT_MACHINE in
>>> the recipe as it was left as a fallback in case user needed it and the
>>> value was different from newer releases.
>>>
>>> In your case, the easier is to make a new yourmachine.conf and use the
>>> UBOOT_CONFIG or UBOOT_MACHINE setting there so it will work just fine.
>>>
>> If I have to do that, then I have to do that.
>>
>> However if I could just undefine one of the two variables defined in the
>> meta-fsl-arm
>> layer then I could continue with what I am doing without having to spend
>> the time
>> right now to rework the configuration, which is wasted effort for me, as
>> I will be moving
>> up to the new version of u-boot in the near future.
>>
>> Is there no simple way to undefine a variable in a recipe?
> You can change the recipe byhand. This is ugly and I wouldn't do it. I
> do think you are wasting more time trying to 'workaround' it than
> fixing it.

Or indeed, would be not be reasonable to modify the uboot-config.bbclass
such that
it tested for and discarded empty strings in UBOOT_MACHINE / UBOOT_CONFIG
which would seem to be a more complete test and would eliminate the
problem ?

> Comment the UBOOT_MACHINE setting in the u-boot-imx recipe and move
> on. The log is clear you're not setting the PREFERRED_VERSION
> accordingly and you should.
>

You've lost me. Why am I not setting PREFERRED_VERSION accordingly? I have
two recipes in the checkout and I have configured prefer the older one,
which
seems entirely reasonable.