Subject: bug#56682: Fix the long lines font locking related slowdowns

From: Dmitry Gutov <[email-masked]>
Date: Wed, 3 Aug 2022 03:00:41 +0300

On 02.08.2022 19:19, Gregory Heytings wrote:
> 
>>> Try to open the dictionary.json with Emacs on master a month ago.
>>
>> I believe it can also be done with the current master, just after 
>> setting long-line-threshold to the nil value.  Right?
>>
> 
> Indeed.  With master from one month ago it's even more crystal-clear 
> that you see the statu quo ante.

If I set long-line-threshold to nil, does that also disable the 
redisplay optimizations related to long lines?

Ones that caused scrolling delays even after the buffer has been fully 
fontified.