bug#29648: BUG in zless and similar scripts?

[Paul Eggert]

On 12/10/2017 01:26 AM, Michele Venturi wrote:
> As you can see here:https://pastebin.com/Q7fcrYhp
> there is an error in the parameters expansion syntax.
>
> It should be "${LESSMETACHARS:+set}" and not just
> "${LESSMETACHARS+set}". zdiff, zgrep and zmore
> miss a colon in the source code in the same way.

Why is this a bug? I don't see the problem. Can you give an example of 
misbehavior because of the bug?

Perhaps the simplest fix for the bug, once we know what it is, would be 
to remove the workaround for less 394 and earlier, as I doubt whether 
anyone would combine a 'less' that old with new 'gzip'.