Re: Excessive use of `eassert`

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 23 Jan 2024 00:15:03 -0800
> Cc: Alan Mackenzie <acm@muc.de>, Eli Zaretskii <eliz@gnu.org>,
>  emacs-devel@gnu.org
> From: Paul Eggert <eggert@cs.ucla.edu>
> 
> On 2024-01-22 05:20, Stefan Monnier wrote:
> > Compared to the patch I proposed this has the downside that it
> > duplicates the logic between `lisp_h_builtin_lisp_symbol` and
> > `make_lisp_symbol`
> Yes, when --enable-checking is used the tradeoff is: would we rather 
> omit all runtime checking in make_lisp_symbol (the patch you proposed), 
> or omit it only for builtin symbols (the patch I installed)?
> 
> For builtin symbols like Qnil and Qt the runtime checking is not all 
> that useful - if these symbols' data items are improperly aligned Emacs 
> will crash early anyway. For non-builtin symbols the runtime checking is 
> arguably useful, to catch (presumably rare) alignment bugs in the memory 
> allocator.
> 
> If you'd rather have the simpler solution that doesn't catch alignment 
> bugs in non-builtin symbols, I could prepare a patch along those lines. 
> Any such alignment bugs are pretty unlikely, after all.

I think we should settle for builtin symbols, since the other kind is
unlikely to cause any significant slowdown, and the extra level of
testing is valuable in debug builds.

I hope Stefan will agree.