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

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

On Mon, 2025-09-15 at 19:49 +0200, Andreas Naumann wrote:
> Hi Felix,
> 
> 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.
> > +    # This special handling for DPKG_ARCH=all packages is left to the
> > +    # multiarch_virtclass_handler
> > +    if archDiffers:
> >           d.appendVar('BBCLASSEXTEND', ' native')
> >       else:
> >           extend_provides(pn, 'native', d)
> > @@ -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')
> 
> I have now done some more testing and unfortunately find that this 
> causes failures when building the -native variant of some dpkg-raw 
> packages we have.
> 

Hi, do you have an example for such a package? Just to be clear: There
is no "native" variant of a dpkg-raw package. The dpkg-raw packages are
always build on the host architecture (in bitbake terms) and of Debian
arch=all.

> We use them for certain config files and they are 
> intended for the target.
> 

Do these configs contain data that is not the same on all
architectures? If so, DPKG_ARCH="all" is wrong.

> I dont know why exactly they fail and I'm sure 
> this could be fixed, but actually there is no need to build those 
> packages in the native environment.
> 

There is need to do so, as otherwise we emulate the build process which
is super slow.

> So I'm somewhat surprised to see 
> that and could image that this causes confusion for others that dont 
> know about the "all" intricacies as well.

Probably, but in the end we are building a debian system and by that
the users should be aware of the debian architecture specifiers.

> 
> Another observation that I see is that dpkg-prebuilt "any" packages, 
> which are probably in the dependency chain of an "all" package, now are 
> always also built as -native, even though they are needed for the target 
> only.

Same here, even if bitbake tells you that they are build as "-native",
there is no difference in the output, as the binary is simply copied.

Best regards,
Felix

> 
> best,
> Andras
> 
> >   }
> >   addhandler multiarch_virtclass_handler
> >   multiarch_virtclass_handler[eventmask] = "bb.event.RecipePreFinalise"
> 
> -- 
> Andreas Naumann
> 
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