Re: bracket needs to be escaped in variable substitution?

[Antoine]

Issue is not reproduced when using a variable as pattern, and it's not 
related the space character in the pattern:

$ ./bash --norc
bash-5.2$ var="abcd efgh ijkl mnop qrst"
bash-5.2$ pattern=" "
bash-5.2$ string="_"

bash-5.2$ echo "${var//${pattern}/${string}[${string}}"
abcd_[_efgh_[_ijkl_[_mnop_[_qrst

bash-5.2$ echo "${var// /${string}[${string}}"
bash: bad substitution: no closing `}' in ${var// /${string}[${string}}

bash-5.2$ echo "${var//a/${string}[${string}}"
bash: bad substitution: no closing `}' in ${var//a/${string}[${string}}


On 06/10/2022 16:52, Antoine wrote:
> Configuration Information [Automatically generated, do not change]:
> Machine: x86_64
> OS: linux-gnu
> Compiler: gcc
> Compilation CFLAGS: -g -O2
> uname output: Linux z390 5.10.0-16-amd64 #1 SMP Debian 5.10.127-2 
> (2022-07-23) x86_64 GNU/Linux
> Machine Type: x86_64-pc-linux-gnu
>
> Bash Version: 5.2
> Patch Level: 0
> Release Status: release
>
> Description:
>
> Hello,
>
> When using substitution with variables and opening bracket as string 
> "target", the bracket has to be escaped if there is no closing bracket 
> and only when a variable is already used in the string.
>
> It wasn't the behavior or previous bash version.
>
> Repeat-By:
>
> $ ./bash --norc
> bash-5.2$ var1="qwertyuiop asdfghjkl"
> bash-5.2$ var2="_"
> bash-5.2$ echo "${var1// /${var2}[${var2}}"
> bash: bad substitution: no closing `}' in ${var1// /${var2}[${var2}}
>
> # but the following work as expected (escaped bracket):
> bash-5.2$ echo "${var1// /${var2}\[${var2}}"
> qwertyuiop_[_asdfghjkl
>
> # also working as expected (with closing bracket):
> bash-5.2$ echo "${var1// /${var2}[${var2}]}"
> qwertyuiop_[_]asdfghjkl
>
> # also working as expected (no variable before the bracket):
> bash-5.2$ echo "${var1// /[${var2}}"
> qwertyuiop[_asdfghjkl
>
>
> --
> Antoine