Re: [Buildroot] [PATCH next v4 1/1] utils/docker-run: mount and pass BR2_EXTERNAL dirs

["Yann E. MORIN via buildroot" <buildroot@buildroot.org>]

Fiona, All,

On 2026-04-05 17:48 +0200, Fiona Klute spake thusly:
> Am 31.08.24 um 21:19 schrieb Fiona Klute via buildroot:
> > From: "Fiona Klute (WIWA)" <fiona.klute@gmx.de>
> > The BR2_EXTERNAL environment variable is passed into the container,
> > and each path listed in it mounted. This allows using external trees
> > when running a build using utils/docker-run. Testing the existence of
> > the variable instead of a non-empty value allows passing an empty
> > BR2_EXTERNAL variable to disable currently set external trees.
[--SNIP--]
> > diff --git a/utils/docker-run b/utils/docker-run
> > index 1adb02d74e..9579f83ce2 100755
> > --- a/utils/docker-run
> > +++ b/utils/docker-run
> > @@ -90,6 +90,13 @@ if [ "${BR2_DL_DIR}" ]; then
> >       docker_opts+=( --env BR2_DL_DIR )
> >   fi
> > 
> > +if [ -v BR2_EXTERNAL ]; then

As this is a bit unusual (but perfectly legit!), maybe a little comment
above the code to explain the intent:

    # Test the variable exists, not just that it is non-empty,
    # to be able to propagate an empty BR2_EXTERNAL.

But -v is a bashism (that's OK, we're using bash in the shabang), but
the more usual (and POSIXly correct [0]) way is to use something like:

    if [ "${BR2_EXTERNAL+set}" ]; then

(an empty string evaluates to false).

I prefer we use standard constructs when they exist, and are not too
cumbersome to use, rather than bashisms that do not provie that much of
an improvement.

> > +    docker_opts+=( --env BR2_EXTERNAL )
> > +    for br2_ext in ${BR2_EXTERNAL//:/ }; do
> > +        mountpoints+=( "${br2_ext}" )
> > +    done

Why the loop? You can just append-assign the expansion:

    mountpoints+=( ${BR2_EXTERNAL//:/ } )

[0] https://pubs.opengroup.org/onlinepubs/9799919799/utilities/V3_chap02.html#tag_19_06_02

Regards,
Yann E. MORIN.

> > +fi
> > +
> >   # shellcheck disable=SC2013 # can't use while-read because of the assignment
> >   for dir in $(printf '%s\n' "${mountpoints[@]}" |LC_ALL=C sort -u); do
> >       docker_opts+=( --mount "type=bind,src=${dir},dst=${dir}" )
> > --
> > 2.45.2
> > 
> > _______________________________________________
> > buildroot mailing list
> > buildroot@buildroot.org
> > https://lists.buildroot.org/mailman/listinfo/buildroot
> 

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