It also reproduces in the current devel branch.
$ bash-dev -c 'declare -a arr=(""); declare -p arr'
declare -a arr=()
$ bash-5.0 -c 'declare -a arr=(""); declare -p arr'
declare -a arr=([0]="")
2020-08-05 3:33 andy_bash <andy_b...@objectmail.com>:
> Sorry, the colors got messed up on the last email
It's still messed up. I reformatted:
> Configuration Information [Automatically generated, do not change]:
> Machine: x86_64OS: linux-musl
> Compiler: gcc
> Compilation CFLAGS: -g -O2 -Wno-parentheses -Wno-format-security
> uname output: Linux 37b7613044c1 5..5.7-200.fc31.x86_64 #1 SMP Fri Feb
> 28 17:18:37 UTC 2020 x86_64 GNU/Linux
> Machine Type: x86_64-pc-linux-musl
> Bash Version: 5.1Patch Level: 0
> Release Status: alpha
>
> Description:
>
> Declaring an array and setting it with empty strings ("") in one
> line is bugged in bash 5.1 alpha. This has worked in bash
> 3.2-5.0 without issue.
>
> I first discovered this through a piece of indirection code I
> have:
>
> x=("")
> y="x[@]"
> local z=(${!y+"${!y}"})
>
> Repeat-By:
>
> docker run -it --rm bash:5.1-alpha bash -c '
> function foo(){
> local bug=("" "5" "" 1 "");
> declare -a bug2=("");
> declare -ga bug3=("" "5" "" 1 "");
> local not_bug=("no" "nulls");
> local workaround; workaround=("");
> declare -p bug bug2 bug3 not_bug workaround;
> };
> declare -a bug4=("" "5" "" 1 ""); declare -p bug4; foo'
>
> Results:
> declare -a bug4=([0]="5" [1]="1")
> declare -a bug=([0]="5" [1]="1")
> declare -a bug2=()
> declare -a bug3=([0]="5" [1]="1")
> declare -a not_bug=([0]="no" [1]="nulls")
> declare -a workaround=([0]="")
>
> As you can see, all the empty strings (null strings) are
> missing, except in the workaround
>
> Fix:
>
> Declaring an array with empty strings ("") in one line should
> work, just like it did in bash 3.2-5.0
>
> This original piece of code should also work the same as
> versions 3.2-5.0 too
>
> $ docker run -it --rm bash:5.0 bash -euc '
> > function foo(){
> > local name="${1}[@]";
> > local copy=(${!name+"${!name}"});
> > declare -p copy;
> > };
> > x=("" 5 ""); foo x; foo undeclared_x'
> declare -a copy=([0]="" [1]="5" [2]="")
> declare -a copy=()
> $ docker run -it --rm bash:5.1-alpha bash -euc '
> > function foo(){
> > local name="${1}[@]";
> > local copy=(${!name+"${!name}"});
> > declare -p copy;
> > };
> > x=("" 5 ""); foo x; foo undeclared_x'
> declare -a copy=([0]="5")
> declare -a copy=()
>
> Thanks,-Andy
--
Koichi
