bug#9820: 24.0.90; Behaviour of add-file-local-variable

[Juri Linkov <juri@jurta.org>]

> How about -
> "Local Variables section updated.

That's exactly what these commands purposely do,
and users see as a result, so there is no need
to reiterate the obvious fact in the message.

> To update actual variable values, revisit the file"

If it's more clear, we could change:

  "Revisit file to make this change take effect"

to

  "Revisit file to update actual variable values"

> This way a (message ...) can be issued as soon as any modifications -
> add-or-replace or delete - happen on the buffer.  I think the extra
> intelligence of checking for new value against the old value could be
> dropped altogether. The message is merely meant as a warning, so being
> paranoid and issuing a warning ALWAYS will also serve the purpose well.

After moving this message to modify-file-local-variable,
checking for new value against the old value really makes less sense
because it's unclear what to do for the `delete' operations,
so I removed this check below.

> Would you like to give me a new patch with the warning message pushed to
> modify-* routines (as Stefan suggested).

Please try a new patch:

=== modified file 'lisp/files-x.el'
--- lisp/files-x.el	2011-04-19 13:44:55 +0000
+++ lisp/files-x.el	2011-10-22 15:34:12 +0000
@@ -115,7 +115,7 @@ (defun read-file-local-variable-mode ()
      ((and (stringp mode) (fboundp (intern mode))) (intern mode))
      (t mode))))
 
-(defun modify-file-local-variable (variable value op)
+(defun modify-file-local-variable (variable value op &optional interactive)
   "Modify file-local VARIABLE in Local Variables depending on operation OP.
 
 If OP is `add-or-replace' then delete all existing settings of
@@ -198,10 +198,13 @@ (defun modify-file-local-variable (varia
 	   ((eq variable 'mode) (goto-char beg))
 	   ((null replaced-pos) (goto-char end))
 	   (replaced-pos (goto-char replaced-pos)))
-	  (insert (format "%s%S: %S%s\n" prefix variable value suffix)))))))
+	  (insert (format "%s%S: %S%s\n" prefix variable value suffix)))
+
+	(when interactive
+	  (message "Revisit file to make this change take effect"))))))
 
 ;;;###autoload
-(defun add-file-local-variable (variable value)
+(defun add-file-local-variable (variable value &optional interactive)
   "Add file-local VARIABLE with its VALUE to the Local Variables list.
 
 This command deletes all existing settings of VARIABLE (except `mode'
@@ -213,17 +216,17 @@ (defun add-file-local-variable (variable
 `Local Variables:' and the last line containing the string `End:'."
   (interactive
    (let ((variable (read-file-local-variable "Add file-local variable")))
-     (list variable (read-file-local-variable-value variable))))
-  (modify-file-local-variable variable value 'add-or-replace))
+     (list variable (read-file-local-variable-value variable) t)))
+  (modify-file-local-variable variable value 'add-or-replace interactive))
 
 ;;;###autoload
-(defun delete-file-local-variable (variable)
+(defun delete-file-local-variable (variable &optional interactive)
   "Delete all settings of file-local VARIABLE from the Local Variables list."
   (interactive
-   (list (read-file-local-variable "Delete file-local variable")))
-  (modify-file-local-variable variable nil 'delete))
+   (list (read-file-local-variable "Delete file-local variable") t))
+  (modify-file-local-variable variable nil 'delete interactive))
 
-(defun modify-file-local-variable-prop-line (variable value op)
+(defun modify-file-local-variable-prop-line (variable value op &optional interactive)
   "Modify file-local VARIABLE in the -*- line depending on operation OP.
 
 If OP is `add-or-replace' then delete all existing settings of
@@ -320,10 +323,13 @@ (defun modify-file-local-variable-prop-l
 	      (insert ";"))
 	  (unless (eq (char-before) ?\s) (insert " "))
 	  (insert (format "%S: %S;" variable value))
-	  (unless (eq (char-after) ?\s) (insert " "))))))))
+	  (unless (eq (char-after) ?\s) (insert " "))))))
+
+    	(when interactive
+	  (message "Revisit file to make this change take effect"))))
 
 ;;;###autoload
-(defun add-file-local-variable-prop-line (variable value)
+(defun add-file-local-variable-prop-line (variable value &optional interactive)
   "Add file-local VARIABLE with its VALUE to the -*- line.
 
 This command deletes all existing settings of VARIABLE (except `mode'
@@ -334,15 +340,15 @@ (defun add-file-local-variable-prop-line
 then this function adds it."
   (interactive
    (let ((variable (read-file-local-variable "Add -*- file-local variable")))
-     (list variable (read-file-local-variable-value variable))))
-  (modify-file-local-variable-prop-line variable value 'add-or-replace))
+     (list variable (read-file-local-variable-value variable) t)))
+  (modify-file-local-variable-prop-line variable value 'add-or-replace interactive))
 
 ;;;###autoload
-(defun delete-file-local-variable-prop-line (variable)
+(defun delete-file-local-variable-prop-line (variable &optional interactive)
   "Delete all settings of file-local VARIABLE from the -*- line."
   (interactive
-   (list (read-file-local-variable "Delete -*- file-local variable")))
-  (modify-file-local-variable-prop-line variable nil 'delete))
+   (list (read-file-local-variable "Delete -*- file-local variable") t))
+  (modify-file-local-variable-prop-line variable nil 'delete interactive))
 
 (defvar auto-insert) ; from autoinsert.el