[oe] [Bitbake-dev] A new bitbake extension: .bbappend files

[Frans Meulenbroeks]

2010/7/16 Richard Purdie <rpurdie at rpsys.net>

> On Fri, 2010-07-16 at 11:46 -0400, Michael Smith wrote:
> > Richard Purdie wrote:
> > > The idea is that if bitbake finds any X.bbappend files, when it loads
> > > X.bb, it will also include these files after it parses the base .bb
> file
> > > (but before finalise and the anonymous methods run). This means that
> > > the .bbappend file can poke around and do whatever it might want to the
> > > recipe to customise it.
> >
> > Does this do anything different than amendrecipes.bbclass?
>
> Several people have mentioned the amend bbclass. This implements
> something very similar in quite a different way as part of the bitbake
> tool itself. There are advantages and disadvantages to doing this.
>
> The features I liked about the bbappend approach was the small amount of
> code change required to bitbake compared to the functionality it offers
> and also the overhead of the bbappend code is minimal.
>
> I also feel the bbappend format is slightly easier for users to
> comprehend but that is subjective.
>
> A downside is that the .bbappend applies to specific versions, not all
> versions as amend.bbclass can be setup. There are ways that could be
> changed.
>
> The amend class has a greater degree of flexibility in that you can make
> changes to the class and it could be argued not changing the core is an
> advantage too.
>
> Cheers,
>
> Richard,

Looks like a fine idea to me (although I must say I was unaware of the amend
class, so I cannot really compare).

An alternative I was thinking of was to have a mechanism in an overlayed
recipe that would allow you to include whatever version was in a lower
priority overlay, but your prososal looks also quite sound.

+1

Frans