Re: for loop over parameter expansion of array can miss resulted empty list

[Alexey]

nullglob is not applicable in this situation, because no 'Pathname 
Expansion' is occur.

On 2022-03-21 14:40, Alex fxmbsw7 Ratchev wrote:

> i solve this by shopt -s nullglob
>
> On Sun, Mar 20, 2022, 22:07 Alexey via Bug reports for the GNU Bourne 
> Again SHell <bug-bash@gnu.org> wrote:
>
> > Hello.
> >
> > Machine: x86_64
> > OS: linux-gnu
> > Compiler: gcc
> > Compilation CFLAGS: -g -O2 -fstack-protector-strong -Wformat
> > -Werror=format-security -Wall
> > uname output: Linux alex 5.16.0-3-amd64 #1 SMP PREEMPT Debian 
> > 5.16.11-1
> > (2022-02-25) x86_64 GNU/Linux
> > Machine Type: x86_64-pc-linux-gnu
> >
> > Bash Version: 5.1
> > Patch Level: 16
> > Release Status: release
> >
> > Description:
> > If use 'Parameter Expansion', for example 'Remove matching suffix
> > pattern', on array and try to iterate over expansion result with for
> > loop, may occur that loop body will not be executed at all.
> >
> > Repeat-By:
> > Code: x=("/"); for i in "${x[@]%/}"; do echo "i is '$i'"; done
> > Result: none
> > Expected result: i is ''
> >
> > Expected behavior:
> > like for an array with empty element
> > Code: x=(""); for i in "${x[@]}"; do echo "i is '$i'"; done
> > Result: i is ''
> >
> > another example, show that problems occurs only with empty resulted
> > list
> > Code: x=("/" "//"); for i in "${x[@]%/}"; do echo "i is '$i'"; done
> > Result: i is ''
> > i is '/'
> >
> > Regards,
> > Alexey