Re: functions can fully unset local vars in other scopes

[Robert E. Griffith]

I just finished reading that 2018 discussion and the current discussion.

Its hard for me to understand why this is an issue. kre's use case was

   unset X
   y=$X

He called it 'braindead' for it to do anything expect to assign 
NULL/empty to Y but I think that is far from true. If he's thinking of 
'unset X' as assigning a NULL value to X (distinct from ""), 'local X' 
(with no initialize) seems to be a much clearer way to do that.

What are people trying to accomplish by unsetting a variable in a 
function that did not first declare it? (besides upVar which 
specifically exploits the long standing behavior).

--BobG

On 8/1/22 09:58, Chet Ramey wrote:
> On 7/30/22 8:05 AM, Kerin Millar wrote:
>
> > > What consideration was given to creating “local --unset *VAR*” or 
> > > “unset
> > > --local *VAR*” or some other equivalent that doesn't overload any 
> > > existing
> > > command form?
> >
> > Obviously, only Chet can meaningfully respond to this. I mentioned 
> > the existence of the option because it appeared likely that Emanuele 
> > was unaware of it, not to attempt to obviate any of his suggestions, 
> > nor endorse the status quo.
>
> Sometimes it's useful to read the discussion that prompted the change.
>
> https://lists.gnu.org/archive/html/bug-bash/2018-02/msg00065.html
>
> In this case, the primary requirement was to enable scripts that wanted a
> wholesale behavior change, while not breaking backwards compatibility by
> making that option the default. Enabling these semantics on a 
> per-variable
> basis wasn't part of the discussion (kre was, however, very vocal about
> making localvar_unset the default).