When sending a bash file to dpaste.org, bash scripts are seen as "python".
#!/bin/bash
shopt -s extglob
case $1 in
[a-z])
echo indent OK. Case '[a-z]'
;;
+([1-9]))
echo indent NOK. Case '+([1-9])', extended pattern.
;;
*)
echo indent still NOK. Case '*', after extended pattern
;;
esac # indent still NOK
The buffer is correct (sh-mode), and shebang is correct. I did not test this behavior for other providers.