outline.el fix for bug#7619.

It turns out the use of nil in the :type of outline regexp was for
very hysterical raisons.  Prior to 2001-09-12T20:42:08Z!rms@gnu.org, the
default value was nil, then it was initialized afterwards.
Everywhere in the code assumes it cannot be nil, so no need to allow
that any more.

* lisp/outline.el (outline-regexp): No longer allow nil.
(outline-heading-end-regexp): Add safety predicate.

2 files changed, 6 insertions, 2 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index c550cd4e852..094143343fb 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,5 +1,8 @@
 2011-03-04  Glenn Morris  <rgm@gnu.org>
 
+        * outline.el (outline-regexp): No longer allow nil.
+        (outline-heading-end-regexp): Add safety predicate.  (Bug#7619)
+
         * net/browse-url.el (browse-url):
         Handle deleted default-directory.  (Bug#6077)
 
diff --git a/lisp/outline.el b/lisp/outline.el
index d43afd94a3c..cedc55b3336 100644
--- a/lisp/outline.el
+++ b/lisp/outline.el
@@ -50,9 +50,9 @@ Note that Outline mode only checks this regexp at the start of a line,
 so the regexp need not (and usually does not) start with `^'.
 The recommended way to set this is with a Local Variables: list
 in the file it applies to.  See also `outline-heading-end-regexp'."
-  :type '(choice regexp (const nil))
+  :type 'regexp
   :group 'outlines)
-;;;###autoload(put 'outline-regexp 'safe-local-variable 'string-or-null-p)
+;;;###autoload(put 'outline-regexp 'safe-local-variable 'stringp)
 
 (defcustom outline-heading-end-regexp "\n"
   "Regular expression to match the end of a heading line.
@@ -62,6 +62,7 @@ The recommended way to set this is with a `Local Variables:' list
 in the file it applies to."
   :type 'regexp
   :group 'outlines)
+;;;###autoload(put 'outline-heading-end-regexp 'safe-local-variable 'stringp)
 
 (defvar outline-mode-prefix-map
   (let ((map (make-sparse-keymap)))