Re: question about, why does my code work in normal bash but not bash devel

[Chet Ramey]

On 4/24/22 5:08 PM, alex ratchev wrote:
> the mkmenu in the script
> and the printf menustr .. it prints a wanted menu by bash 5.1.16 , but on
> 5.2b from ~ a week ago it prints empty

You're not going to get the variable expansion you want in the subscript:

 mkmenu() {
declare var
menustr=
  for var in $( compgen -A function ) ; do
 [[ -v help[\$var] ]] ||
continue
menustr+="$var <- ${help[$var]}"$'\n'
  done
 }

because you quoted it too much. This is what this CHANGES entry means:

k. Bash attempts to expand indexed array subscripts only once when executing
   shell constructs and word expansions.

though it should say `indexed and associative'. In bash-5.2, bash tries to
behave as if `assoc_expand_once' is set when expanding associative array
subscripts for shell compound commands and parameter expansions. You can
set BASH_COMPAT=51 to get the behavior you want.

There was a pretty spirited discussion about this last year:

https://lists.gnu.org/archive/html/bug-bash/2021-03/msg00056.html

and the bash-5.2 behavior -- which is much safer -- can be reverted with
the compatibility mode.

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/