Re: mark_object crash in 22.1 and latest CVS (as of tonight)

[Stefan Monnier]

>     The `evaporate' option is inherently dangerous since it reclaims the
>     marker object forcefully without checking that nobody else is holding on
>     to it, even tho it comes from a plain normal argument and the caller may
>     very well have kept another ref to it somewhere.

> There are low-level constructs in Emacs that can crash Emacs if misused.
> This mere fact is not enough reason to get rid of it.

It's an "optimization" and nothing more.  In my book, if an optimization
is unsafe, it had better make a good case for itself.  As it stands
I see no evidence that this optimization is ever useful.  As long as
nobody can show us numbers that demonstrate a measurable performance
impact, I think we're better off without this optimization.


        Stefan