[OE-core] Weird ALTERNATIVES and staging conflict.

[Richard Purdie]

On Mon, 2014-11-03 at 12:35 +0100, Mike Looijmans wrote:
> On 11/03/2014 11:49 AM, Mike Looijmans wrote:
> > On 11/03/2014 11:04 AM, Richard Purdie wrote:
> >> On Mon, 2014-11-03 at 10:53 +0100, Mike Looijmans wrote:
> >>> On 10/30/2014 06:47 PM, Richard Purdie wrote:
> >>>> On Thu, 2014-10-30 at 15:17 +0100, Mike Looijmans wrote:
> >>>>> I have this base script that builds FPGA bitstreams:
> >>>>>
> >>>>> https://github.com/topic-embedded-products/meta-topic/blob/master/recipes-bsp/fpga/fpga-image.inc
> >>>>>
> >>>>>
> >>>>> Now you can have multiple recipes using it, and as such, it seemed a good
> >>>>> idea
> >>>>> to add these lines to that recipe:
> >>>>>
> >>>>> +ALTERNATIVE_${PN} = "fpga.bin bitstreams"
> >>>>> +ALTERNATIVE_LINK_NAME[fpga.bin] = "${datadir}/fpga.bin"
> >>>>> +ALTERNATIVE_TARGET[fpga.bin] = "${datadir}/fpga.bin"
> >>>>> +ALTERNATIVE_LINK_NAME[bitstreams] = "${datadir}/bitstreams"
> >>>>> +ALTERNATIVE_TARGET[bitstreams] = "${datadir}/bitstreams"
> >>>>>
> >>>>>
> >>>>> This still resulted in staging conflicts.
> >>>>
> >>>> This isn't surprising since update-alternatives only works for target
> >>>> systems. It is not designed for operating on the sysroot.
> >>>
> >>> I don't want these files in sysroot, I want them on target only.
> >>
> >> Ok, that makes things much easier.
> >>
> >>>>> But looking at the contents of the fake packages, the fpga.bin has been
> >>>>> renamed by alternatives (as expected), and the symlink will be created after
> >>>>> installing, so how come I still get this?
> >>>>
> >>>> The "staging" code uses the output of do_install directly and does
> >>>> different things to the packaging code path. We've never had someone
> >>>> with this problem before. Binaries in *bindir only get installed into
> >>>> the sysroot in the -native case.
> >>>>
> >>>> I appreciate that tells you why it doesn't work and not how to fix it
> >>>> but hopefully that helps a bit.
> >>>
> >>> If I understand you correctly, the problem is that the recipe is trying to
> >>> install things in sysroot?
> >>
> >> Correct, by default ${datadir} is staged. The easiest way to handle this
> >> may be to define your own sysroot_stage_all function (or
> >> sysroot_stage_dirs) which just stages what you need, if anything.
> >
> > In other words, make  sysroot_stage_all into a no-op?
> >
> > I've been looking at the staging.bbclass, but that's basically the best I can
> > come up with.
> 
> Ah, slightly better:
> 
> # Prevent bitstreams ending up in sysroot.
> sysroot_stage_dirs_append() {
> 	rm -rf $to${datadir}/fpga.bin $to${datadir}/bitstreams
> }
> 
> This wastes a bit (installing multimegabyte bitstreams only to remove them) 
> but it won't interfere with recipes that do wish to install things in sysroot.
> 
> I've tested with this now, and this appears to do exactly as I wanted.

That is fine and perfectly acceptable. Just to be clear, you can also
do:

sysroot_stage_all() {
	:
}

in your recipe and it will only affect that recipe, not all recipes.

Cheers,

Richard