[oe] additional bitbake test

[Frans Meulenbroeks]

2010/5/28 Chris Larson <clarson at kergoth.com>:
> On Thu, May 27, 2010 at 11:36 PM, Frans Meulenbroeks <
> fransmeulenbroeks at gmail.com> wrote:
>
>> Hi,
>>
>> I'd like to propose to add a test in bitbake to see if an overlay dir
>> exists when specifying overlays.
>>
>> In the past I bumped into a problem where BBFILE_PATTERN_local =
>> "^${OE_TOPDIR}/myoverlay/recipes" was not processed properly because
>> OE_TOPDIR was not passed using BB_ENV_EXTRAWHITE, resulting in the
>> regexp match with the dir always returning false due to OE_TOPDIR not
>> being expanded.
>> A simple test could warn users against errors like this one.
>>
>
> Hmm, I'm not sure how best to implement the warning.  I'd rather not grep,
> and we don't currently have a way to determine what variables a given value
> references.  I guess we could notice if a given pattern didn't match any
> files in BBFILES, and warn on that.  Does that sound reasonable?

That sounds quite good to me.
>
> Aside: the fact that a nonexistant var is left as is, to be expanded in
> shell, is horrible, imo.  They should expand to the empty string when unset,
> or error, or something.

I'm inclined to say error. If a default it wanted an assignment can be
done somewhere.
Better make the problem explicit

Frans