Re: [docs] [PATCH] ref-manual: clarify use of "PACKAGE_ARCH" in a packagegroup

On Fri, 19 Jun 2026, Quentin Schulz wrote:

> Hi Robert,
>
> On 6/16/26 6:46 PM, Robert P. J. Day via lists.yoctoproject.org wrote:
> >
> > Warn the developer that if they need to set "PACKAGE_ARCH" in a
> > custom packagegroup file, that setting must precede the "inherit
> > packagegroup" line in the packagegroup recipe file.
> >
> > Signed-off-by: Robert P. J. Day <[email protected]>
> >
> > ---
> >
> > diff --git a/documentation/ref-manual/classes.rst
> > b/documentation/ref-manual/classes.rst
> > index 95e07f85a..839a89d4b 100644
> > --- a/documentation/ref-manual/classes.rst
> > +++ b/documentation/ref-manual/classes.rst
> > @@ -2130,6 +2130,18 @@ section in the Yocto Project Development Tasks
> > Manual.
> >
> >   Previously, this class was called the ``task`` class.
> >
> > +.. note::
> > +
> > +   If you're defining a packagegroup and need to set::
> > +
> > +      PACKAGE_ARCH = ${MACHINE_ARCH}
> > +
>
> OK so reading this I was like "but who would need to do this? packagegroups
> are only supposed to include other packages and not compile anything!
>
> Then I looked in OE-Core, and there are as many packagegroups with
> PACKAGE_ARCH set than without. It seems that the need comes from using
> MACHINE_FEATURES or other knobs that depend on some configuration variable.
>
> I think it'd be nice to document this (if not already, but since you're
> scouring the docs now maybe you'd come across something like that?).
>
> I'm thinking this is a big enough footgun that we may want to document the
> order in the variable glossary as well.

  amusingly, the current packagegroup-core-base-utils.bb opens with
the duplication:

  PACKAGE_ARCH = "${MACHINE_ARCH}"

  inherit packagegroup

  VIRTUAL-RUNTIME_vim ?= "vim-tiny"

  PACKAGE_ARCH = "${MACHINE_ARCH}"       <==== ????

"git blame" shows that second line added 2019-07-23:

    packagegroup-core-base-utils: Make it machine specific

    Recipe makes use of the variable MACHINE_FEATURES, which is machine
    specific:

      ${@bb.utils.contains("MACHINE_FEATURES", "keyboard", "kbd", "", d)}

then two days later, from the same person, the first line being added
with the same commit message.

  i'm guessing that second assignment to PACKAGE_ARCH is unnecessary.

rday