bug#36591: 26.2; Term's pager seems broken

[Eli Zaretskii <eliz@gnu.org>]

> From: Noam Postavsky <npostavs@gmail.com>
> Cc: Lars Ingebrigtsen <larsi@gnus.org>,  abliss@gmail.com,  36591@debbugs.gnu.org
> Date: Wed, 24 Jul 2019 20:55:38 -0400
> 
> > I would like to leave connect_network_socket alone on the release
> > branch, and just fix the problem with set-process-filter.  I think the
> > easiest way is simply not to call set_process_filter_masks in
> > set-process-filter, and instead restore the way that code worked
> > before 9755b753, i.e. let it test the argument FILTER _before_ that
> > filter is installed.  Do you see any problems with this fix?
> 
> I think that makes sense, patch attached.

Thanks, this patch is OK for the emacs-26 branch.

> > On the master branch we should clean up the confusing set of if
> > clauses, both in set-process-filter and in connect_network_socket.
> > Perhaps Lars could describe his reasoning for making the change which
> > introduced set_process_filter_masks and what problem it tried to
> > solve.  (Btw, the log message for that change seems to imply that
> > set-process-filter should not have called set_process_filter_masks,
> > something that the change itself disagrees with.  An omission?)
> 
> Hmm, true, I didn't pay that close attention to the log message.
> Maybe "we may not have a socket yet" refers to the already existing
> 'if (p->infd >= 0)' check?

Let's see what Lars remembers, and let's then take it from there.