Add `enable-dir-local-variables'

* lisp/files.el (enable-dir-local-variables): New variable.
(hack-dir-local-variables): Respect enable-dir-local-variables.

* lisp/tutorial.el (help-with-tutorial): Ignore directory-local variables.

Fixes: debbugs:11127

3 files changed, 19 insertions, 7 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 5b80c1dbdbe..979c0808b7b 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,5 +1,10 @@
 2013-02-11  Glenn Morris  <rgm@gnu.org>
 
+        * files.el (enable-dir-local-variables): New variable.
+        (hack-dir-local-variables): Respect enable-dir-local-variables.
+        * tutorial.el (help-with-tutorial):
+        Ignore directory-local variables.  (Bug#11127)
+
         * vc/vc-svn.el (vc-svn-command): Move --non-interactive from here...
         (vc-svn-global-switches): ... to here.  (Bug#13513)
 
diff --git a/lisp/files.el b/lisp/files.el
index c9e5d2763fe..890834d4af0 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -507,6 +507,11 @@ and ignores this variable."
                  (other :tag "Query" other))
   :group 'find-file)
 
+(defvar enable-dir-local-variables t
+  "Non-nil means enable use of directory-local variables.
+Some modes may wish to set this to nil to prevent directory-local
+settings being applied, but still respect file-local ones.")
+
 ;; This is an odd variable IMO.
 ;; You might wonder why it is needed, when we could just do:
 ;; (set (make-local-variable 'enable-local-variables) nil)
@@ -3659,8 +3664,12 @@ is found.  Returns the new class name."
 (defun hack-dir-local-variables ()
   "Read per-directory local variables for the current buffer.
 Store the directory-local variables in `dir-local-variables-alist'
-and `file-local-variables-alist', without applying them."
+and `file-local-variables-alist', without applying them.
+
+This does nothing if either `enable-local-variables' or
+`enable-dir-local-variables' are nil."
   (when (and enable-local-variables
+             enable-dir-local-variables
              (or enable-remote-dir-locals
                  (not (file-remote-p (or (buffer-file-name)
                                          default-directory)))))
diff --git a/lisp/tutorial.el b/lisp/tutorial.el
index 011461119fc..39eb9e8b9aa 100644
--- a/lisp/tutorial.el
+++ b/lisp/tutorial.el
@@ -829,10 +829,9 @@ Run the Viper tutorial? "))
             (progn
               (insert-file-contents (tutorial--saved-file))
               (let ((enable-local-variables :safe)
-                    (enable-local-eval nil))
+                    (enable-local-eval nil)
+                    (enable-dir-local-variables nil)) ; bug#11127
                 (hack-local-variables))
-              ;; FIXME?  What we actually want is to ignore dir-locals (?).
-              (setq buffer-read-only nil) ; bug#11118
               (goto-char (point-min))
               (setq old-tut-point
                     (string-to-number
@@ -849,10 +848,9 @@ Run the Viper tutorial? "))
               (setq tutorial--point-before-chkeys (point-marker)))
           (insert-file-contents (expand-file-name filename tutorial-directory))
           (let ((enable-local-variables :safe)
-                (enable-local-eval nil))
+                (enable-local-eval nil)
+                (enable-dir-local-variables nil)) ; bug#11127
             (hack-local-variables))
-          ;; FIXME?  What we actually want is to ignore dir-locals (?).
-          (setq buffer-read-only nil) ; bug#11118
           (forward-line)
           (setq tutorial--point-before-chkeys (point-marker)))