lock file not removed when trap is inside an "if"

Question

I put my trap inside an if, run the script, and after that second execution, it warns that lock file is held (ok). But when I kill -9 the running PID, the lockfile is not removed.

When I move trap before the if (what you can see now commented below):

1. then when I kill -9 PID, lockfile is deleted (ok)
2. but when I run additional executions the scripts, only first one warns because after this first-additional run, the lockfile is removed by trap on EXIT!

How to get the trap inside if to remove the lockfile on kill -9 of the script?

lockfile=/tmp/localfile
#trap 'rm -f "$lockfile"; exit $?' INT TERM EXIT KILL
if ( set -o noclobber; echo "$$" > "$lockfile") 2> /dev/null;
then
    trap 'rm -f "$lockfile"; exit $?' INT TERM EXIT KILL
    while true
    do
        ls -ld ${lockfile}
        sleep 1
    done
    rm -f "$lockfile"
    trap - INT TERM EXIT
else
    echo "Failed to acquire lockfile: $lockfile."
    echo "Held by $(cat $lockfile)"
fi

Answer 1

kill -KILL (or kill -9) kills the process without it being able to clean up. The SIGKILL signal is non-trappable by design.

Use a plain kill (sends TERM by default) instead.

See also: Why should I not use 'kill -9' / SIGKILL