[bitbake-devel] DEPENDS vs RDEPENDS from bitbake PoV

Masahiro Yamada masahiroy at kernel.org
Sat Dec 28 17:14:45 UTC 2019


On Sat, Dec 28, 2019 at 9:16 PM Richard Purdie
<richard.purdie at linuxfoundation.org> wrote:
>
> On Wed, 2019-12-25 at 16:33 +0900, Masahiro Yamada wrote:
> > So, DEPENDS and RDEPENDS are fundamentally the same
> > from the bitbake point of view.
> > Is my understanding correct?
>
> From that perspective, yes, they both have the same dependency
> behaviour.
>
> > I know there is slight difference between them.
> > For the RDEPENDS variant, the form RDEPENDS_<pkg> is also supported.
> > (<pkg> is the element in ${PACKAGES}, or ${PN} if ${PACKAGES} is
> > empty).
> >
> > Other than that, the functionality looks the same between
> > DEPENDS and RDEPENDS.
>
> The namespace difference is key, deptask works off DEPENDS, rdeptask of
> RDEPENDS and as you mention, RDEPENDS has a relationship with PACKAGES
> and RDEPENDS_<pkg>.
>
> Cheers,
>
> Richard


Thanks, it helped me a lot.


If bitbake had been implemented as a really generic task scheduler,
perhaps it would have chosen more sophisticated syntax than DEPENDS/RDEPENDS.

As a new learner, I think one of the most difficult parts to understand
is the boundary/interface between bitbake and meta data.

The metadata-level specification is nibbling at bitbake.
I decided to convince myself that it is how this project goes...


-- 
Best Regards
Masahiro Yamada


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