Re: [PATCH 2/2] handle DPKG_ARCH=all case for transitive deps

["'MOESSBAUER, Felix' via isar-users" <isar-users@googlegroups.com>]

On Wed, 2025-09-10 at 13:00 +0200, Andreas Naumann wrote:
> Hi Felix, all,
> 
> Am 20.08.25 um 14:41 schrieb 'Felix Moessbauer' via isar-users:
> > Arch=all packages might build depend on other arch=all packages, hence we
> > need to correctly model the dependency chain. Otherwise the transitive
> > dependencies are built for the distro arch instead of the native arch.
> > 
> > We implement this by dispatching the non-native variant of DPKG_ARCH=all
> > packages to the -native variant by adding a dependency. We further
> > replace the non-native do_deploy_dep task with a noop to preserve the
> > dependency chain.
> > 
> > Co-developed-by: Adriaan Schmidt <adriaan.schmidt@siemens.com>
> > Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
> > ---
> >   meta/classes/multiarch.bbclass | 18 +++++++++++++++++-
> >   1 file changed, 17 insertions(+), 1 deletion(-)
> > 
> > diff --git a/meta/classes/multiarch.bbclass b/meta/classes/multiarch.bbclass
> > index babdfbd4..c2bba21f 100644
> > --- a/meta/classes/multiarch.bbclass
> > +++ b/meta/classes/multiarch.bbclass
> > @@ -29,7 +29,11 @@ python() {
> >               d.appendVar('BBCLASSEXTEND', ' compat')
> >   
> >       # build native separately only when it differs from the target variant
> > -    if not archIsAll and archDiffers:
> > +    # We must not short-circuit for DPKG_ARCH=all packages, as they might
> > +    # have transitive dependencies which need to be built for -native.
> 
> Funny enough i suspected to have the same problem yesterday, but it 
> turned out to
> be different: When a package is single architecture only, e.g. arm64, it 
> should not be
> extended as native if HOST_ARCH is amd64.
> 
> So I added a check to BBCLASSEXTEND only if DPKG_ARCH != HOST_ARCH.

Good catch. This case is currently not handled. But I would like to
have it in a separate patch, as it tackles another issue.

> 
> > +    # This special handling for DPKG_ARCH=all packages is left to the
> > +    # multiarch_virtclass_handler
> > +    if archDiffers:
> >           d.appendVar('BBCLASSEXTEND', ' native')
> Now, seeing your patch to remove the not-"all" case also, I wonder if 
> that could be used
> as the sole check before BBCLASSEXTEND. Like e.g.
> archIsNative = d.getVar('DPKG_ARCH') == d.getVar('HOST_ARCH')
> if isNative:
>     d.appendVar('BBCLASSEXTEND', ' native')
> >       else:
> >           extend_provides(pn, 'native', d)
> 
> but now I wonder what the extend_provides is needed for. If HOST_ARCH == 
> DISTRO_ARCH, what's
> the use of providing a native variant?

If we are building for the native arch, we can just add the -native
variants to the PROVIDES, so dependencies of packages depending
explicitly on <foo>-native can be resolved (without the need for extra
recipe variants).

> 
> But back to your Patch: Is it possible that -compat "all" packages also have
> dependencies on other "all" packages, which in turn have dependencies on
> architecture specific packages?

Good question. In general, package dependencies are resolved for the
native architecture (or the requested one). AFAIK this selection is
propagated down the dependency tree. By that, A:i386 -> B:all -> C:x
should always resolve C as either :all or i386 (except if there is a
explicit cross-arch dependency specifier like :any, which we don't
model in bitbake). Anyways, The A:i386 -> B:all -> C:i386 chain should
already be resolved correctly with this patch.

Tested by's are welcome :)

Felix

> 
> regards,
> Andreas
> 
> 
> > @@ -86,6 +90,8 @@ python multiarch_virtclass_handler() {
> >               d.setVar(var, ' '.join(multiarch_var))
> >   
> >       pn = e.data.getVar('PN')
> > +    archDiffers = d.getVar('HOST_ARCH') != d.getVar('DISTRO_ARCH')
> > +    archIsAll = d.getVar('DPKG_ARCH') == 'all'
> >       if pn.endswith('-compat'):
> >           e.data.setVar('BPN', pn[:-len('-compat')])
> >           e.data.appendVar('OVERRIDES', ':class-compat')
> > @@ -96,6 +102,16 @@ python multiarch_virtclass_handler() {
> >           e.data.appendVar('OVERRIDES', ':class-native')
> >           fixup_pn_in_vars(e.data)
> >           fixup_depends('-native', e.data)
> > +    elif archIsAll and archDiffers:
> > +        # Arch=all packages might build depend on other arch=all packages,
> > +        # hence we need to correctly model the dependency chain.
> > +        # We implement this by dispatching the non-native variant to the -native
> > +        # variant by adding a dependency. We further replace the non-native
> > +        # do_deploy_dep task with a noop to preserve the dependency chain.
> > +        e.data.setVar('do_deploy_deb', '')
> > +        bb.build.deltask('deploy_deb', e.data)
> > +        bb.build.addtask('deploy_deb', 'do_build', '', e.data)
> > +        e.data.setVarFlag('do_deploy_deb', 'depends', f'{pn}-native:do_deploy_deb')
> >   }
> >   addhandler multiarch_virtclass_handler
> >   multiarch_virtclass_handler[eventmask] = "bb.event.RecipePreFinalise"
> 
> -- 
> Andreas Naumann
> 
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