(make-auto-save-file-name): Make name always end in #,

i.e. overwrite third char in extension if required.

1 files changed, 10 insertions, 4 deletions

diff --git a/lisp/files.el b/lisp/files.el
index dadf9c95a4b..969da941f89 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -2342,10 +2342,16 @@ Does not consider `auto-save-visited-file-name' as that variable is checked
 before calling this function.  You can redefine this for customization.
 See also `auto-save-file-name-p'."
   (if buffer-file-name
-      (concat (file-name-directory buffer-file-name)
-              "#"
-              (file-name-nondirectory buffer-file-name)
-              "#")
+      (if (eq system-type 'ms-dos)
+          (let ((fn (file-name-nondirectory buffer-file-name)))
+                (string-match "\\`\\([^.]+\\)\\(\\.\\(..?\\)?.?\\|\\)\\'" fn)
+            (concat (file-name-directory buffer-file-name)
+                    "#" (match-string 1 fn) 
+                    "." (match-string 3 fn) "#"))
+        (concat (file-name-directory buffer-file-name)
+                "#"
+                (file-name-nondirectory buffer-file-name)
+                "#"))
 
     ;; Deal with buffers that don't have any associated files.  (Mail
     ;; mode tends to create a good number of these.)