Another way to solve this according https://github.com/koalaman/shellcheck/wiki/SC2086:

Quoting this doesn't work, since in the default case, "$debug" would expand to one empty argument while $debug would expand into zero arguments. In this case, you can use an array with zero or one elements as outlined above, or you can use an unquoted expansion with an alternate value:

debug=""
[[ $1 == "--trace-commands" ]] && debug="yes"
bash ${debug:+"-x"} script

This is better than an unquoted value because the alternative value can be properly quoted, e.g. wget ${output:+ -o "$output"}.

Regression introduced in rOPSbf659c5728cbfeab65c1fba8772f2037278000b5:

Ok, but typo to fix.

Could be presented in January as "one year of open source :: 2020 retrospective" with added insights?

Imported from https://github.com/nasqueron/docker-openfire/pull/1