"Locked narrowing" added in Emacs 29 cannot be (temporarily) canceled by code called inside. This in particular breaks Logview (
https://github.com/doublep/logview), because this narrowing is in effect during fontification and causes Logview to fall down into an infinite loop. Moreover, variable `restrictions-locked' appears to be not exposed to Elisp, meaning that this cannot be cleared even with an explicit let-bind.
The mode simply cannot work without an ability to temporarily widen the text. Macro `logview--std-temporarily-widening' is used 35 times in its code:
(defmacro logview--std-temporarily-widening (&rest body)
(declare (indent 0) (debug t))
`(save-restriction
(let ((logview--point-min (logview--point-min))
(logview--point-max (logview--point-max)))
(widen)
,@body)))
To make it even harder to debug, Emacs sometimes hangs completely with even C-g not aborting faulty code (in this case "faulty" because of incompatible changes in Emacs itself).
Paul