international/mule-cmds.el (prefer-coding-system): Show a warning message if the default value of file-name-coding-system was not changed.

2 files changed, 10 insertions, 1 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 37286d0780c..f900c7dfa50 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2011-12-30  Kenichi Handa  <handa@m17n.org>
+
+        * international/mule-cmds.el (prefer-coding-system): Show a
+        warning message if the default value of file-name-coding-system
+        was not changed.
+
 2011-12-29  Michael Albinus  <michael.albinus@gmx.de>
 
         * net/tramp-sh.el (tramp-find-shell): Set "remote-shell" property
diff --git a/lisp/international/mule-cmds.el b/lisp/international/mule-cmds.el
index 0d3f079866e..94b5724c016 100644
--- a/lisp/international/mule-cmds.el
+++ b/lisp/international/mule-cmds.el
@@ -418,7 +418,10 @@ To prefer, for instance, utf-8, say the following:
     (if (memq eol-type '(0 1 2))
         (setq base
               (coding-system-change-eol-conversion base eol-type)))
-    (set-default-coding-systems base)))
+    (set-default-coding-systems base)
+    (if (called-interactively-p 'interactive)
+        (or (eq base default-file-name-coding-system)
+            (message "The default value of `file-name-coding-system' was not changed because the specified coding system is not suitable for file names.")))))
 
 (defvar sort-coding-systems-predicate nil
   "If non-nil, a predicate function to sort coding systems.