Avoid invalid regexp in wide docstring check

* lisp/emacs-lisp/bytecomp.el (byte-compile--wide-docstring-p):
Avoid constructing an invalid regexp during byte-compilation by
limiting the number of columns to the current RE_DUP_MAX of 65535.
This protects against pathological values of fill-column, for
example (bug#49426).

diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index 70999648d47eb43461837623c221a906b216b489..6970c8a5055e8eedc6daea35012f5d63547cb071 100644 (file)
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -1627,7 +1627,7 @@ the `\\\\=[command]' ones that are assumed to be of length
 `byte-compile--wide-docstring-substitution-len'.  Also ignore
 URLs."
   (string-match
-   (format "^.\\{%s,\\}$" (int-to-string (1+ col)))
+   (format "^.\\{%d,\\}$" (min (1+ col) #xffff)) ; Heed RE_DUP_MAX.
    (replace-regexp-in-string
     (rx (or
          ;; Ignore some URLs.