Deprecate using "mode:" to enable minor modes (bug#8613)

* lisp/files.el (hack-one-local-variable-eval-safep):
Consider "eval: (foo-mode)" to be safe.

* doc/emacs/custom.texi (Specifying File Variables):
Deprecate using mode: for minor modes.

* etc/NEWS: Mention this.

* lisp/doc-view.el, lisp/net/soap-client.el:
Change "mode:" minor-mode file local variables to use "eval:".

7 files changed, 43 insertions, 24 deletions

diff --git a/doc/emacs/ChangeLog b/doc/emacs/ChangeLog
index b417e806245..d3521dcd524 100644
--- a/doc/emacs/ChangeLog
+++ b/doc/emacs/ChangeLog
@@ -1,3 +1,8 @@
+2011-05-10  Glenn Morris  <rgm@gnu.org>
+
+        * custom.texi (Specifying File Variables):
+        Deprecate using mode: for minor modes.
+
 2011-05-07  Glenn Morris  <rgm@gnu.org>
 
         * cal-xtra.texi (Sexp Diary Entries): Mention diary-hebrew-birthday.
diff --git a/doc/emacs/custom.texi b/doc/emacs/custom.texi
index 7a696df319b..d7a99d49d60 100644
--- a/doc/emacs/custom.texi
+++ b/doc/emacs/custom.texi
@@ -1085,9 +1085,8 @@ first line:
 You can specify any number of variable/value pairs in this way, each
 pair with a colon and semicolon as shown above.  The special
 variable/value pair @code{mode: @var{modename};}, if present,
-specifies a major or minor mode; if you use this to specify a major
-mode, it should come first in the line.  The @var{value}s are used
-literally, and not evaluated.
+specifies a major mode, and should come first in the line.  The
+@var{value}s are used literally, and not evaluated.
 
 @findex add-file-local-variable-prop-line
 @findex delete-file-local-variable-prop-line
@@ -1186,7 +1185,7 @@ list:
 
 @itemize
 @item
-@code{mode} enables the specified major or minor mode.
+@code{mode} enables the specified major mode.
 
 @item
 @code{eval} evaluates the specified Lisp expression (the value
@@ -1213,10 +1212,11 @@ variables as part of their initialization.
   You can use the @code{mode} ``variable'' to enable minor modes as
 well as the major modes; in fact, you can use it more than once, first
 to set the major mode and then to enable minor modes which are
-specific to particular buffers.
+specific to particular buffers.  Using @code{mode} for minor modes
+is deprecated, though---instead, use @code{eval: (minor-mode)}. 
 
-  Often, however, it is a mistake to enable minor modes this way.
-Most minor modes, like Auto Fill mode, represent individual user
+  Often, however, it is a mistake to enable minor modes in file local
+variables.  Most minor modes, like Auto Fill mode, represent individual user
 preferences.  If you want to use a minor mode, it is better to set up
 major mode hooks with your init file to turn that minor mode on for
 yourself alone (@pxref{Init File}), instead of using a local variable
diff --git a/etc/NEWS b/etc/NEWS
index 9e9778c6ac1..7da456dfc3d 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -267,6 +267,10 @@ default, all themes included in Emacs are treated as safe.
 ** The user option `remote-file-name-inhibit-cache' controls whether
 the remote file-name cache is used for read access.
 
++++
+** The use of a "mode: minor" specification in a file local variables section
+to enable a minor-mode is deprecated.  Instead, use "eval: (minor-mode)".
+
 ** The standalone programs lib-src/digest-doc and sorted-doc have been
 replaced with Lisp commands `doc-file-to-man' and `doc-file-to-info'.
 
diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index cbb03baa3bf..50c3022ba0a 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,4 +1,10 @@
 2011-05-10  Glenn Morris  <rgm@gnu.org>
+           Stefan Monnier  <monnier@iro.umontreal.ca>
+
+        * files.el (hack-one-local-variable-eval-safep):
+        Consider "eval: (foo-mode)" to be safe.  (Bug#8613)
+
+2011-05-10  Glenn Morris  <rgm@gnu.org>
 
         * calendar/diary-lib.el (diary-list-entries-hook)
         (diary-mark-entries-hook, diary-nongregorian-listing-hook)
diff --git a/lisp/doc-view.el b/lisp/doc-view.el
index ab0d6bf837b..7bd1a55011e 100644
--- a/lisp/doc-view.el
+++ b/lisp/doc-view.el
@@ -1549,7 +1549,7 @@ See the command `doc-view-mode' for more information on this mode."
 (provide 'doc-view)
 
 ;; Local Variables:
-;; mode: outline-minor
+;; eval: (outline-minor-mode)
 ;; End:
 
 ;;; doc-view.el ends here
diff --git a/lisp/files.el b/lisp/files.el
index 72cfc89ef8c..336a0a436f9 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -3327,21 +3327,25 @@ It is dangerous if either of these conditions are met:
       ;; Certain functions can be allowed with safe arguments
       ;; or can specify verification functions to try.
       (and (symbolp (car exp))
-           (let ((prop (get (car exp) 'safe-local-eval-function)))
-             (cond ((eq prop t)
-                    (let ((ok t))
-                      (dolist (arg (cdr exp))
-                        (unless (hack-one-local-variable-constantp arg)
-                          (setq ok nil)))
-                      ok))
-                   ((functionp prop)
-                    (funcall prop exp))
-                   ((listp prop)
-                    (let ((ok nil))
-                      (dolist (function prop)
-                        (if (funcall function exp)
-                            (setq ok t)))
-                      ok)))))))
+           ;; Allow (minor)-modes calls with no arguments.
+           ;; This obsoletes the use of "mode:" for such things.  (Bug#8613)
+           (or (and (null (cdr exp))
+                    (string-match "-mode\\'" (symbol-name (car exp))))
+               (let ((prop (get (car exp) 'safe-local-eval-function)))
+                 (cond ((eq prop t)
+                        (let ((ok t))
+                          (dolist (arg (cdr exp))
+                            (unless (hack-one-local-variable-constantp arg)
+                              (setq ok nil)))
+                          ok))
+                       ((functionp prop)
+                        (funcall prop exp))
+                       ((listp prop)
+                        (let ((ok nil))
+                          (dolist (function prop)
+                            (if (funcall function exp)
+                                (setq ok t)))
+                          ok))))))))
 
 (defun hack-one-local-variable (var val)
   "Set local variable VAR with value VAL.
diff --git a/lisp/net/soap-client.el b/lisp/net/soap-client.el
index b5453733d1d..9862332bf3f 100644
--- a/lisp/net/soap-client.el
+++ b/lisp/net/soap-client.el
@@ -1745,7 +1745,7 @@ operations in a WSDL document."
 
 
 ;;; Local Variables:
-;;; mode: outline-minor
+;;; eval: (outline-minor-mode)
 ;;; outline-regexp: ";;;;+"
 ;;; End: