Containerfile: how to prevent missing build argument warning from spamming the console?

[GrabbenD]

Question

I have multiple static variables which are repeating a lot between stages and I'd like to declare them in one place to make the code easier to follow.

What I've tried

My current approach to copying variables between stages is ARG as seen in this example:

ARG BUILDDIR=/mnt

FROM archlinux:base AS rootfs
ARG BUILDDIR
RUN echo Result: $BUILDDIR
# Result: /mnt

FROM scratch AS host
ARG BUILDDIR
COPY --from=rootfs / /
RUN echo Result: ${BUILDDIR}
# Result: /mnt

However, this spams a lot of warning messages about missing build args:

WARN[0000] missing "BUILDDIR" build argument. Try adding "--build-arg BUILDDIR=" to the command line
WARN[0000] missing "BUILDDIR" build argument. Try adding "--build-arg BUILDDIR=" to the command line

I've also tried ENV but the value isn't copied between stages:

FROM archlinux:base AS rootfs
ENV BUILDDIR=/mnt
RUN echo Result: $BUILDDIR
# Result: /mnt

FROM scratch AS host
COPY --from=rootfs / /
RUN echo Result: ${BUILDDIR}
# Result: 

I know it's just a warning but I'd like to keep messages which needs attention to minimal (warnings/errors/..)

Is there any other way of copying variables between stages without producing warning messages?

[Luap99]

@flouthoc PTAL

[flouthoc]

Thanks this is fixed with: containers/buildah#4983, once recent buildah is vendored you will not see this warnings on globally decalared args.