ci: set -u in cirrus.sh to treat unset variables as an error #1154

for loop and without echo -n which is not POSIX (I don't think we really care in CI but so far we tried to stick to POSIX)

    for var in CC CFLAGS AR NM; do
        eval "isset=\${$var+x}"
        if [ -n "$isset" ]; then
            eval "val=\${$var}"
            # shellcheck disable=SC2154
            printf '%s="%s" ' "$var" "$val"
        fi
    done

Can't find the point where shellcheck is called... Did I miss a script in CI?

With the suggested loop, why do separate CC, CFLAGS, AR and NM variables from others? A tiny overhead for a check seems an acceptable tradeoff for the succinct code, no?

With the suggested loop, why do separate CC, CFLAGS, AR and NM variables from others? A tiny overhead for a check seems an acceptable tradeoff for the succinct code, no?

Oh indeed. If we have a working loop that handles arbitrary variables, we should use it for all variables. Actually this makes me more convinced of my suggestion than I was before (the eval is somehwat ugly but having one piece of code for all env variables is probably a good idea.) @jonasnick What do you think?

Can't find the point where shellcheck is called... Did I miss a script in CI?

Sorry, I called it locally on my machine. :D I've seen it being very useful a few times in Core, and so I thought it doesn't hurt to add the shellcheck comment here (even if maintainers use locally). Perhaps we want to add it in the future. If @jonasnick picks up this suggestion at all, I'll let him decide if the comment is appropriate / consistent without running shellcheck in CI. ;)

I've seen it being very useful a few times in Core,

Indeed.

Thanks @real-or-random, with your snippet I was able to merge these variables with the loop above. I'd keep the shellcheck directive, since I'm using shellcheck locally.