Re: [OE-core] [PATCH v3 2/4] meta: Support opting out of any distro features

[Paul Barker <paul@pbarker.dev>]

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On Wed, 2026-04-22 at 21:26 +0100, Jose Quaresma wrote:
> Jose Quaresma via lists.openembedded.org <quaresma.jose=
> gmail.com@lists.openembedded.org> escreveu (quarta, 22/04/2026 à(s) 15:45):
> 
> > Hi Paul,
> > 
> > I think I found a bug that is somehow related to DISTRO_FEATURES_DEFAULTS.
> > I don't understand why, but the variables in
> > DISTRO_FEATURES_DEFAULTS cannot
> > be used in inherit or inherit_defer.
> > 
> > Let's use the following recipe as an example:
> > 
> > -------------------------------------------------------------------------------------------------------------------
> > mkdir -p recipes-test/inherit
> > cat <<'EOF' >recipes-test/inherit/inherit.bb
> > 
> > LICENSE = "MIT"
> > 
> > # FAIL
> > PACKAGECONFIG ??= " \
> >         ${@bb.utils.contains('DISTRO_FEATURES',
> > 'gobject-introspection-data', 'ccache', '', d)} \
> >         ${@bb.utils.contains('DISTRO_FEATURES',
> > 'gobject-introspection-data', 'vala', '', d)} \
> > "
> > 
> > # OK
> > #PACKAGECONFIG ??= " \
> > #        ${@bb.utils.contains('DISTRO_FEATURES', 'systemd', 'ccache', '',
> > d)} \
> > #        ${@bb.utils.contains('DISTRO_FEATURES', 'systemd', 'vala', '',
> > d)} \
> > #"
> > 
> > # get PACKAGECONFIG
> > # bitbake-getvar -r inherit PACKAGECONFIG
> > 
> > # get CCACHE_TOP_DIR
> > # bitbake-getvar -r inherit CCACHE_TOP_DIR
> > inherit_defer ${@bb.utils.filter('PACKAGECONFIG', 'ccache', d)}
> > 
> > # get VALADEPENDS
> > # bitbake-getvar -r inherit VALADEPENDS
> > inherit_defer ${@bb.utils.filter('PACKAGECONFIG', 'vala', d)}
> > EOF
> > 
> > -------------------------------------------------------------------------------------------------------------------
> > 
> 
> A clearer way to replicate the problem:
> 
> #
> -------------------------------------------------------------------------------------------------------------------
> mkdir -p recipes-test/inherit
> cat <<'EOF' >recipes-test/inherit/inherit.bb
> LICENSE = "MIT"
> 
> DISTRO_FEATURES_DEFAULTS += "aaa"
> DISTRO_FEATURES += "bbb"
> 
> PACKAGECONFIG = " \
>         ${@bb.utils.contains('DISTRO_FEATURES', 'aaa', 'ccache', '', d)} \
>         ${@bb.utils.contains('DISTRO_FEATURES', 'bbb', 'vala', '', d)} \
> "
> 
> inherit_defer ${@bb.utils.filter('PACKAGECONFIG', 'ccache', d)}
> 
> inherit_defer ${@bb.utils.filter('PACKAGECONFIG', 'vala', d)}
> EOF
> #
> -------------------------------------------------------------------------------------------------------------------
> bitbake-getvar --value -r inherit PACKAGECONFIG
> bitbake-getvar --value -r inherit CCACHE_TOP_DIR
> bitbake-getvar --value -r inherit VALADEPENDS
> #
> -------------------------------------------------------------------------------------------------------------------
> 
> 
> The DISTRO_FEATURES is mapped to inherit/inherit_defer as follows:
>  'aaa' maps to  'ccache'
>  'bbb' maps to  'vala'
> 
> I chose these two classes, but it could be any others. The idea is to see
> if they were inherited by looking at the class variables.
> The ccache.bbclass was not inherit and so the variable 'CCACHE_TOP_DIR' is
> not defined.
> 
> 
> Hence my conclusion that DISTRO_FEATURES_DEFAULTS doesn't work for these
> cases, which in my opinion is not expected.
> 
> I encountered this problem while debugging the patch
> https://lists.openembedded.org/g/openembedded-devel/topic/118939974.
> 
> Best regards,
> Jose
> 

Hi Jose,

We can simplify this even further to demonstrate what bitbake is doing:

    LICENSE = "MIT"

    python () {
        d.setVar('MAYBE_VALA', 'vala')
    }

    inherit_defer ${@bb.utils.filter('MAYBE_VALA', 'vala', d)}

Looking at the output of `bitbake -e`, MAYBE_VALA is set to "vala" but
the vala bbclass is not included.

If we simplify the last line to `inherit_defer ${MAYBE_VALA}` we get a
parse error. It also doesn't work with plain inherit.

This contadicts the example in the bitbake docs [1], which suggests that
a variable assigned in an anonymous Python block can be used with
inherit_defer.

[1]: https://docs.yoctoproject.org/bitbake/dev/bitbake-user-manual/bitbake-user-manual-metadata.html#inherit-defer-directive

I will investigate further!

Best regards,

-- 
Paul Barker


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