Re: Should write-contents-functions be permanent-local?

[Eli Zaretskii]

> From: Joseph Turner <joseph@breatheoutbreathe.in>
> Date: Mon, 14 Aug 2023 23:35:44 -0700
> 
> WDYT about making write-contents-functions permanent-local?

That cannot be done, sorry.  Some modes set this to mode-specific
values, you can find this even in the Emacs source tree.  But even
without those examples, a variable that were not permanent-local for
so long cannot be suddenly made permanent-local, because it will
almost certainly break something somewhere.

In any case, if you are okay with making the variable permanent-local,
then why not just

  (put 'write-contents-functions 'permanent-local t)

in your package, and be done with it?  The effect of the above is the
same global effect as if we would do that by default in Emacs, right?