bug#55832: 28.1; Emacs crashes when using tramp from helm in emacs-29

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: Thierry Volpiatto <thievol@posteo.net>,  55832@debbugs.gnu.org
> Date: Wed, 08 Jun 2022 20:17:05 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Sounds like C stack overflow trying to print a too-long variable-arg
> > list? 
> 
> If that's the problem, then perhaps this problem is fixed in Emacs 29 --
> Mattias has reimplemented the printer to not be recursive (because
> printing certain very deep structures will segfault Emacs versions
> before 29).

The non-recursive implementation of the printer AFAIU only helps when
we need to print a deeply-recursive Lisp structure.  Here, if I'm
right, the problem is that the va_arg argument list is too long -- and
all of them are pushed onto the C stack.

So Mattias's changes could only help in this case if the complete
backtrace will show recursive calls to print_object etc.