Bug: buffer local variables handled wrong [9.0.5 (release_9.0.5-497-g5bc540 @ /home/hs/.emacs.d/lib/org-mode/lisp/)]

["Stefan-W. Hahn" <stefan.hahn@s-hahn.de>]

Good day,

Emacs  : GNU Emacs 26.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.18.9)
 of 2017-05-20
Package: Org mode version 9.0.5 (release_9.0.5-497-g5bc540 @ /home/hs/.emacs.d/lib/org-mode/lisp/)

I use a minor mode (moccur-edit-mode, seems a little bit old) which
initializes one variable in this way:

,----
| (defvar moccur-edit-old-content)
| (make-local-variable 'moccur-edit-old-content)
`----

This leads to following result in (buffer-local-variables):

,----
| ... (moccur-edit-file-overlays) moccur-edit-old-content (company-prefix) ...
`----

I think this is correct and happens not only by the used minor-mode.

When doing org-capture now I got a lisp error:

Debugger entered--Lisp error: listp moccur-edit-old-content

This error comes from org-clone-local-variables, because there the
prediction for local variables is always to be a list.

I traced all other code points where (buffer-local-variables) is used:

,----
| grep --color -nH -e buffer-local-var *.el
| 1. org-agenda.el:2158:	 (let ((save (buffer-local-variables)))
| 2. org.el:9401:	   (buffer-local-variables)))))
| 3. org.el:9406:  (dolist (pair (buffer-local-variables from-buffer))
| 4. org-element.el:4091:   (t (let ((local-variables (buffer-local-variables)))
| 5. ox.el:2646:	     (dolist (entry (buffer-local-variables (buffer-base-buffer)) vars)
`----

The code 2., 4. and 5. are correct, they use (consp v) or (symbolp v) to
decide what to do.

The code 1. and 3. are wrong. They both work directly with (car v) or
(cdr v).

For 1. and 3. I would like to suggest the following corrections:

modified   lisp/org-agenda.el
@@ -2159,11 +2159,12 @@ org-agenda-mode
 	   (kill-all-local-variables)
 	   (mapc 'make-local-variable org-agenda-local-vars)
 	   (dolist (elem save)
-	     (let ((var (car elem))
-		   (val (cdr elem)))
-	       (when (and val
-			  (member var org-agenda-local-vars))
-		 (set var val)))))
+	     (if (consp elem)
+		 (let ((var (car elem))
+		       (val (cdr elem)))
+		   (when (and val
+			      (member var org-agenda-local-vars))
+		     (set var val))))))
 	 (setq-local org-agenda-this-buffer-is-sticky t))
 	(org-agenda-sticky
 	 ;; Creating a sticky Agenda buffer for the first time
modified   lisp/org.el
@@ -9404,11 +9404,12 @@ org-clone-local-variables
   "Clone local variables from FROM-BUFFER.
 Optional argument REGEXP selects variables to clone."
   (dolist (pair (buffer-local-variables from-buffer))
-    (let ((name (car pair)))
-      (when (and (symbolp name)
-		 (not (memq name org-unique-local-variables))
-		 (or (null regexp) (string-match regexp (symbol-name name))))
-	(set (make-local-variable name) (cdr pair))))))
+    (if (consp pair)
+	(let ((name (car pair)))
+	  (when (and (symbolp name)
+		     (not (memq name org-unique-local-variables))
+		     (or (null regexp) (string-match regexp (symbol-name name))))
+	    (set (make-local-variable name) (cdr pair)))))))
 
 ;;;###autoload
 (defun org-run-like-in-org-mode (cmd)


With kind regards,
Stefan

-- 
Stefan-W. Hahn                          It is easy to make things.
                                        It is hard to make things simple.