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

[Peter Wang]

I came across the problem when I was using `C-u C-x =' on a SLIME

presentation. After some debugging, I found out the cause of the

problem. Here is it:

In a slime REPL buffer, when the evaluation result is rendered, SLIME

adds text properties using `slime-add-presentation-properties'. One

of the text properties is a syntax-table `slime-presentation-syntax-table'.

`C-u C-x =' calls `(describe-char (point))', which in turn calls

`describe-text-properties', which hangs with 100% cpu usage.

I think a possible fix could be done in `describe-property-list', adding

a case in cond to handle the type of syntax-table, something like:

diff --git a/lisp/descr-text.el b/lisp/descr-text.el

index 6c7983a177..926103f35e 100644

--- a/lisp/descr-text.el

+++ b/lisp/descr-text.el

@@ -90,6 +90,7 @@ describe-property-list

       'type 'help-face 'help-args (list value)))

             ((widgetp value)

      (describe-text-widget value))

+            ((syntax-table-p value) (insert "#<syntax table>"))

     (t

      (describe-text-sexp value))))

     (insert "\n")))