Partial fix for bug #12989 with buffer-file-type annoyances.

 lisp/subr.el (buffer-file-type): Declare with defvar-local.  Doc fix.
 lisp/dos-w32.el (find-file-not-found-set-buffer-file-coding-system):
 Don't set buffer-file-type.  Return nil.

3 files changed, 14 insertions, 6 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 54997776eff..e264746c691 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,10 @@
+2012-11-26  Eli Zaretskii  <eliz@gnu.org>
+
+        * subr.el (buffer-file-type): Declare with defvar-local.  Doc fix.
+
+        * dos-w32.el (find-file-not-found-set-buffer-file-coding-system):
+        Don't set buffer-file-type.  (Bug#12989)
+
 2012-11-26  Glenn Morris  <rgm@gnu.org>
 
         * hippie-exp.el (hippie-expand-try-functions-list):
diff --git a/lisp/dos-w32.el b/lisp/dos-w32.el
index 4839d6b9239..cb043ce8559 100644
--- a/lisp/dos-w32.el
+++ b/lisp/dos-w32.el
@@ -210,7 +210,7 @@ set to the appropriate coding system, and the value of
                      (untranslated-file-p (buffer-file-name))))
         (setq coding (coding-system-change-eol-conversion coding 0))
         (setq buffer-file-coding-system coding))
-      (setq buffer-file-type (eq buffer-file-coding-system 'no-conversion)))))
+      nil)))
 
 ;;; To set the default coding system on new files.
 (add-hook 'find-file-not-found-functions
diff --git a/lisp/subr.el b/lisp/subr.el
index 2088c7887b3..aeaab20bd47 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -2632,13 +2632,14 @@ When the hook runs, the temporary buffer is current.
 This hook is normally set up with a function to put the buffer in Help
 mode.")
 
-;; Avoid compiler warnings about this variable,
-;; which has a special meaning on certain system types.
-(defvar buffer-file-type nil
+(defvar-local buffer-file-type nil
   "Non-nil if the visited file is a binary file.
-This variable is meaningful on MS-DOG and Windows NT.
+This variable is meaningful on MS-DOG and MS-Windows.
 On those systems, it is automatically local in every buffer.
-On other systems, this variable is normally always nil.")
+On other systems, this variable is normally always nil.
+
+WARNING: This variable is obsolete and will disapper Real Soon Now.
+Don't use it!")
 
 ;; The `assert' macro from the cl package signals
 ;; `cl-assertion-failed' at runtime so always define it.