bug#25156: 26.0.50; `describe-text-properties' hangs with 100% cpu usage when property is a char-table

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Peter Wang <ptr.wang@gmail.com> writes:

> BTW, I also found that `describe-variable' has the same problem.
>
> (describe-variable 'lisp-mode-syntax-table)
>
> I have not looked into this yet, it could be the same bug.
>
> On Sat, Dec 10, 2016 at 11:03 PM, Peter Wang <ptr.wang@gmail.com> wrote:
>
>  A simplest test case is like:
>
>  (describe-property-list (list 'syntax-table lisp-mode-syntax-table))
>
>  evaluating this Elisp expression will hang with 100% CPU usage.

Neither of these hang for me from emacs -Q, using latest master (fc0fd24c105b)

(benchmark 1 '(describe-variable 'lisp-mode-syntax-table)) ;=> "Elapsed time: 
1.272053s (0.161946s in 6 GCs)"
(benchmark 1 '(describe-property-list (list 'syntax-table 
lisp-mode-syntax-table))) ;=> "Elapsed time: 1.165824s (0.139516s in 5 GCs)"