On Thu, Jul 11, 2024 at 15:39:41 -0400, Lawrence Velázquez wrote:
> I won't speculate about the issue, but your subject goes too far.
> The variable really is unset here:
>
> % cat /tmp/x.bash
> x() {
> local x=y
> declare -p x
> echo "x is ${x-unset}"
> unset x
> declare -p x
> echo "x is ${x-unset}"
> }
>
> x
> % bash /tmp/x.bash
> declare -- x="y"
> x is y
> declare -- x
> x is unset
It looks like newer versions of bash retain *some* memory of the unset
local variable's name, but not its flags or prior contents.
hobbit:~$ f() { local -i x=0; declare -p x; unset x; declare -p x; }
hobbit:~$ f
declare -i x="0"
declare -- x
Lawrence is spot on with the semantics, though. The unset variable
behaves exactly like a variable that was never set.
hobbit:~$ g() { local -i x=0; unset x; echo "plus:${x+plus} minus:${x-minus}";}
hobbit:~$ g
plus: minus:minus
So the question is why Werner's associate cares enough about the output
of declare -p to call this a bug, rather than a simple change of internal
implementation.
Is there some actual semantic difference in behavior between bash versions
that we need to be concerned about here?
