(set-visited-file-name): Rename the old auto save file.

1 files changed, 15 insertions, 11 deletions

diff --git a/lisp/files.el b/lisp/files.el
index 3782a794727..66adbba5f20 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -1093,17 +1093,21 @@ if you wish to pass an empty string as the argument."
        (progn
          (make-local-variable 'backup-inhibited)
          (setq backup-inhibited t)))
-  ;; If auto-save was not already on, turn it on if appropriate.
-  (if (not buffer-auto-save-file-name)
-      (and buffer-file-name auto-save-default
-           (auto-save-mode t))
-    ;; If auto save is on, start using a new name.
-    ;; We deliberately don't rename or delete the old auto save
-    ;; for the old visited file name.  This is because perhaps
-    ;; the user wants to save the new state and then compare with the
-    ;; previous state from the auto save file.
-    (setq buffer-auto-save-file-name
-          (make-auto-save-file-name)))
+  (let ((oauto buffer-auto-save-file-name))
+    ;; If auto-save was not already on, turn it on if appropriate.
+    (if (not buffer-auto-save-file-name)
+        (and buffer-file-name auto-save-default
+             (auto-save-mode t))
+      ;; If auto save is on, start using a new name.
+      ;; We deliberately don't rename or delete the old auto save
+      ;; for the old visited file name.  This is because perhaps
+      ;; the user wants to save the new state and then compare with the
+      ;; previous state from the auto save file.
+      (setq buffer-auto-save-file-name
+            (make-auto-save-file-name)))
+    ;; Rename the old auto save file if any.
+    (and oauto buffer-auto-save-file-name
+         (rename-file oauto buffer-auto-save-file-name t)))
   (if buffer-file-name
       (set-buffer-modified-p t)))