Re: why can't we use "vared" in a subshell in interactive shells?

[Bart Schaefer <schaefer@brasslantern.com>]

On Sat, Feb 8, 2020 at 11:37 AM Stephane Chazelas <stephane@chazelas.org> wrote:
>
> $ (vared -c var)
> vared: ZLE not enabled
>
> Why?

Looks like an overlooked side-effect to me.  The assumption being made
is that in interactive mode, if USEZLE is false then it's because the
user has explicitly unsetopt'd it, not because it was temporarily
disabled on entry to a subshell.

There are two ways we could go here:
1) Assume that if the user has invoked vared, then it's OK to run ZLE
even if it was otherwise turned off, and just remove that test
entirely.  (The check for TERM == emacs is mostly obsolete anyway, if
we're attempting to do that we should be looking for [absense of]
certain terminfo values, not a specific terminal type.)
2) Figure out some way to remember the old state of USEZLE when
entering the subshell, and check that in bin_vared instead of checking
the current state.