bug#57804: An infinite loop in a `fontify-region' function causes Emacs to hang indefinitely

[Eli Zaretskii <eliz@gnu.org>]

> From: Paul Pogonyshev <pogonyshev@gmail.com>
> Date: Wed, 14 Sep 2022 19:25:09 +0200
> Cc: 57804@debbugs.gnu.org
> 
> > >   (while t
> > >     "whoopsie")
> 
> It is no wonder that Emacs is in such a poor state with 2 out 3
> responding developers failing to make _one_ mental step from "while t"
> to "this could be a 100-line loop that accidentally falls into
> infinite recursion".  And even because of incompatible change in Emacs
> itself.

Emacs gives Lisp programmers enough rope to hang themselves, and
expects them to be wise enough not to do so.  Our own sources should
not use so much rope, so if there are such loops in our code, please
point them out, or show a recipe that uncovers them, and we will
certainly fix them.

But preventing programmers from writing infinite loops for the benefit
of writing infinite loops, and in font-lock functions on top of that,
is not my idea of good investment of our resources.  It is much easier
to fix such infinite loops so they aren't there in the first place.

> Just wish I didn't get accustomed to this pile of crap 20 years ago
> and just used a normal IDE like every smart person.

You are welcome.