bug#60346: VC refresh error "Recursive load"

[Eli Zaretskii]

> Date: Mon, 26 Dec 2022 13:26:17 -0800
> From:  Joseph Turner via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> I wanted to ignore byte-compiled files because edebug was refusing to
> step into byte-compiled functions.
> 
> I ran the following:
> 
> emacs -Q --eval="(setq load-suffixes '(\".el\"))"
> 
> This broke basic functionality, throwing a "Recursive load" error. For
> example, `M-x find-file ~/.emacs.d/init.el` gives:
> 
> VC refresh error: (error "Recursive load" 
> "/gnu/store/x8nykb09aqmp2j6k74dpgc4jvbk8c2bl-emacs-next-29.0.50-3.22e8a77/share/emacs/29.0.50/lisp/jka-compr.el.gz"
>  
> "/gnu/store/x8nykb09aqmp2j6k74dpgc4jvbk8c2bl-emacs-next-29.0.50-3.22e8a77/share/emacs/29.0.50/lisp/jka-compr.el.gz"
>  
> "/gnu/store/x8nykb09aqmp2j6k74dpgc4jvbk8c2bl-emacs-next-29.0.50-3.22e8a77/share/emacs/29.0.50/lisp/jka-compr.el.gz"
>  
> "/gnu/store/x8nykb09aqmp2j6k74dpgc4jvbk8c2bl-emacs-next-29.0.50-3.22e8a77/share/emacs/29.0.50/lisp/jka-compr.el.gz"
>  
> "/gnu/store/x8nykb09aqmp2j6k74dpgc4jvbk8c2bl-emacs-next-29.0.50-3.22e8a77/share/emacs/29.0.50/lisp/jka-compr.el.gz"
>  
> "/gnu/store/x8nykb09aqmp2j6k74dpgc4jvbk8c2bl-emacs-next-29.0.50-3.22e8a77/share/emacs/29.0.50/lisp/vc/vc-git.el.gz")
> load-with-code-conversion: Recursive load: 
> "/gnu/store/x8nykb09aqmp2j6k74dpgc4jvbk8c2bl-emacs-next-29.0.50-3.22e8a77/share/emacs/29.0.50/lisp/jka-compr.el.gz",
>  
> "/gnu/store/x8nykb09aqmp2j6k74dpgc4jvbk8c2bl-emacs-next-29.0.50-3.22e8a77/share/emacs/29.0.50/lisp/jka-compr.el.gz",
>  
> "/gnu/store/x8nykb09aqmp2j6k74dpgc4jvbk8c2bl-emacs-next-29.0.50-3.22e8a77/share/emacs/29.0.50/lisp/jka-compr.el.gz",
>  
> "/gnu/store/x8nykb09aqmp2j6k74dpgc4jvbk8c2bl-emacs-next-29.0.50-3.22e8a77/share/emacs/29.0.50/lisp/jka-compr.el.gz",
>  
> "/gnu/store/x8nykb09aqmp2j6k74dpgc4jvbk8c2bl-emacs-next-29.0.50-3.22e8a77/share/emacs/29.0.50/lisp/jka-compr.el.gz",
>  
> "/gnu/store/x8nykb09aqmp2j6k74dpgc4jvbk8c2bl-emacs-next-29.0.50-3.22e8a77/share/emacs/29.0.50/lisp/vc/vc-git.el.gz"
> 
> Emacs also breaks when load-suffixes are reordered:
> 
> emacs -Q --eval="(setq load-suffixes '(\".el\" \".so\" \".elc\"))"
> 
> I am running Guix on a foreign distro Debian Bullseye. Shall I send this
> issue to the Guix mailing list instead?

I'm not sure we want to support this kind of changes in the order or
contents of load-suffixes.  It sounds to me like the order is there
for as reason, and no part of Emacs expects these lists to be
reordered, let alone have some extensions removed from them.  I think
the only valid changes are adding extensions to the end.

Stefan, WDYT?