Subject: bug#57207: 29.0.50; Fontification is slow after e7b5912b23 (Improvements to long lines handling)

From: Lars Ingebrigtsen <[email-masked]>
Date: Sun, 21 Aug 2022 15:27:36 +0200

Gregory Heytings <[email-masked]> writes:

> I cannot reproduce that here: after evalling the recipe, typing "bar"
> and then doing M-< bar works as expected.

Here's a full test case.

emacs -Q and then:

(progn
  (pop-to-buffer "foo.txt")
  (flyspell-mode)
  (insert "\n\n"
	  (propertize (make-string 20000 ?x) 'display "foo")
	  "\n\nbar\nzot\n")
  (goto-char (point-min)))
 
Then type `d'.  Everything after "foo" disappears.