Re: Emacs freezes again when I try to open a file including only one very long line.

[Eli Zaretskii <eliz@gnu.org>]

> From: Hongyi Zhao <hongyi.zhao@gmail.com>
> Date: Tue, 28 Jun 2022 20:56:56 +0800
> 
> > > In scratch buffer, `C-x C-e` the following setting:
> > >
> > > (setq max-redisplay-ticks 3000000000000000)
> > >
> > > `C-x C-f` to open the file discussed here. If I drag the scroll bar on
> > > the right side of the window with the mouse, Emacs will lose response,
> > > as shown in the attached file.
> >
> > Why did you set the variable to such a large value?  That effectively
> > disables the feature.  I told you what value I recommend; why didn't
> > you use that?  What were you trying to accomplish by using the value
> > 3000000000000000?
> 
> It's picked from the following relevant discussion:
> 
> https://mail.gnu.org/archive/html/bug-gnu-emacs/2022-06/msg01690.html

Why did you think that value was relevant?

This variable is documented, and its documentation tells you how to
use it.  Please follow the documentation instead of some random
discussion on the bug list.

> Anyway, I tried with your suggested configuration:
> 
> (setq max-redisplay-ticks 250000)
> 
> But the problem remains, as shown in the attached file.

Which problem "remains"?  Don't you see that message at the bottom,
telling you

  Window showing buffer __tmp.symbols takes too long to redisplay

?  It is clearly seen in the screenshot you posted.

If you now type "C-x b RET" or "M-x", doesn't Emacs respond normally,
not after a very long time?

This is what this feature does: it interrupts a too-long redisplay and
lets you use Emacs regardless -- you can switch to another buffer, or
kill the problematic buffer, or do something else to remedy the
unexpected slowness, instead of having to wait forever for any
response to any Emacs command, which basically makes the session
unusable.