[OE-core] why does sysfsutils-2.1.0.bb set S = "${WORKDIR}/sysfsutils-${PV}"?

[Paul Eggleton]

On Friday 23 October 2015 08:57:39 Robert P. J. Day wrote:
> On Fri, 23 Oct 2015, Paul Eggleton wrote:
> > Hi Robert,
> > 
> > On Friday 23 October 2015 08:02:11 Robert P. J. Day wrote:
> > >   side note: the first in a small set of posts where i simply want to
> > > 
> > > clarify minor oddities i run across in oe-core, not because they have
> > > any desperate need to be fixed, but more because when i'm teaching
> > > courses in oe/yocto, i run across the occasional weirdness that
> > > puzzles students, and forces me to try to explain it, and sometimes
> > > the explanation is, "that's just silly." so here's the first one.
> > > 
> > >   as i read in bitbake.conf, the default source directory for any
> > > 
> > > recipe is defined as:
> > >   S = "${WORKDIR}/${BP}"
> > > 
> > > which suggests that, as long as processing a recipe ends up using that
> > > value as the source directory, there is no need for a recipe to
> > > redefine S. kind of obvious, no?
> > > 
> > >   in the case of sysfsutils-2.1.0.bb, one sees the line:
> > > S = "${WORKDIR}/sysfsutils-${PV}"
> > > 
> > > which, given the standard definitions for variables BP and PV, seems
> > > to expand into precisely the default value given in bitbake.conf.
> > > 
> > >   so, unless i'm missing something, is there any actual need for that
> > > 
> > > line in the sysfsutils recipe file? is there something more subtle
> > > going on here that i don't understand?
> > 
> > I don't think so, it appears that line goes way back to the initial
> > population of the repository. Looks like we could just drop it.
> 
>   thanks for the clarification. i realize that stuff like this is
> annoyingly pedantic for developers and expert users, but it's
> *exactly* the kind of thing students in my classes occasionally point
> out and ask me to explain, and i stand there looking kind of baffled,
> muttering, "what the hell ..."

Indeed, having recently been in a classroom situation at the Yocto Project Dev 
Day (standing at the back helpling/heckling the presenter rather than teaching 
;) I know what you mean.

>   i'm about to update all my courseware so i'll just collect as many
> of those as i can find and submit as a single patch.

Great, thanks!

Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre