SC2249.md

Pattern: Missing default case

Issue: -

Description

Found case statement may not be considering all possible cases. This may mean that only the happy paths are accounted for. Consider adding a default case to handle other values. If you don't know what to do or don't believe it'll ever happen, exiting with an error is good, fail-fast practice.

The example is adapted from a real world Debian init script, which due to a missing default case reports success on any misspelled command (here with underscore instead of dash):

$ /etc/init.d/screen-cleanup force_reload && echo success
success

Example of incorrect code:

case "$1" in
  start) start_service ;;
  stop)  stop_service ;;
  restart|reload|force-reload)
    stop_service;
    start_service;;
esac

Example of correct code:

case "$1" in
  start) start_service ;;
  stop)  stop_service ;;
  restart|reload|force-reload)
    stop_service;
    start_service;;
  *)
    echo >&2 "Invalid choice: $1"
    exit 1
esac

Further Reading

• ShellCheck - SC2249