bug#43714: 28.1: auto-revert code improvements [PATCH]

[Eli Zaretskii]

> Date: Wed, 30 Sep 2020 11:28:27 -0400
> From: Boruch Baum <boruch_baum@gmx.com>
> Cc: Lars Ingebrigtsen <larsi@gnus.org>, 43714@debbugs.gnu.org
> 
> On 2020-09-30 17:25, Eli Zaretskii wrote:
> > >     (auto-revert-buffers): Use save-match-data.
> >
> > It could be due to remote files (and file-handlers)?
> 
> But I don't see anywhere in the code itself being evaluated in
> auto-revert.el that would produce its own match-data to potentially
> disturb the pre-existing state.

That's what I meant: it could be hidden from plain sight.

Why is that a problem to leave save-match-data alone?  Does it do any
harm?