qa: Ignore shellcheck warning SC2236 #15164

With shellcheck 0.6.0 the warning SC2236 - Use -n instead of ! -z is raised. This change adds that warning to the ignored list.

Thanks. utACK 98584ff548e267a1dc1d5240e560c623c5287424, let's merge if it fixes travis.

BTW, a similar thing was already done before in 908a559f33.

To prevent this from happening over and over again it might make sense to change to a list of checks to include, instead of a list of checks to exclude. (not sure this is easy to do or would require manually going over the list)

@practicalswift ping.

Concept ACK, but please print the version only when shellcheck had something to say by adding:

if [[ $? != 0 ]]; then
    echo
    shellcheck --version
fi

IMO checks should be silent unless deviations are found. That improves the signal to noise in the output when running multiple checks.

The tweak @laanwj is suggestion can be done in a follow-up PR.

@practicalswift what's the problem of showing the version? Then it's easier to compare between green and red builds.

@promag Travis already prints the shellcheck version by default under "Build system information":

shellcheck version
0.6.0

But more generally we should try to keep the signal to noise as high as possible :-)

Travis already prints the shellcheck version by default under "Build system information":

Oh ty! will remove that.

Done.

utACK f652f85d0c88629b4284f69b179362254307fb55