bug#44818: 27.0.91; wedged

[Eli Zaretskii <eliz@gnu.org>]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: Devon Sean McCullough <Devon2020@jovi.net>,  44818@debbugs.gnu.org
> Date: Tue, 24 Nov 2020 08:04:16 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > When you visit such a long file in Emacs 27.1, you should see a
> > suggestion to visit it literally; take it.
> >
> > A more general solution is to turn on so-long mode.
> 
> This is such a general problem that people bump into all the time that I
> think Emacs should have an even more general solution, and it should be
> on by default.

We generally intended to turn on so-long-mode by default.  We just
didn't get our act together in time for Emacs 27, as there are a few
bits to get straight before we could make it the default.

> The long-file warning isn't sufficient -- there's plenty of smaller
> files that have this problem, too.

so-long-mode is supposed to detect those cases reliably, not just by
file size, but also by line size and other indications.

> Why doesn't Emacs just check for long lines (in the C code, for speed)
> when opening files, and offer the "visit literally?" if it detects them?

That's what so-long-mode does, AFAIR.  It was designed to solve these
use cases, and AFAIR it does that well enough to not need to invent
yet another similar wheel.

We should try to finish the bits that aren't yet finalized, and turn
it on by default as soon as we can.