(backup-buffer-copy): Try to overwrite old backup first.

2 files changed, 21 insertions, 12 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index a7cbdf407cb..76a6a7c4726 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2007-08-30  Martin Rudalics  <rudalics@gmx.at>
+
+        * files.el (backup-buffer-copy): Try to overwrite old backup
+        first.
+
 2007-08-29  Martin Rudalics  <rudalics@gmx.at>
 
         * repeat.el (repeat): Use last-repeatable-command instead of
diff --git a/lisp/files.el b/lisp/files.el
index 69ebf460781..bc482c8f37b 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -3127,18 +3127,22 @@ BACKUPNAME is the backup file name, which is the old file renamed."
           ;; loosen them later, whereas it's impossible to close the
           ;; time-window of loose permissions otherwise.
           (set-default-file-modes ?\700)
-          (while (condition-case ()
-                     (progn
-                       (and (file-exists-p to-name)
-                            (delete-file to-name))
-                       (copy-file from-name to-name nil t)
-                       nil)
-                   (file-already-exists t))
-            ;; The file was somehow created by someone else between
-            ;; `delete-file' and `copy-file', so let's try again.
-            ;; rms says "I think there is also a possible race
-            ;; condition for making backup files" (emacs-devel 20070821).
-            nil))
+          (when (condition-case nil
+                    ;; Try to overwrite old backup first.
+                    (copy-file from-name to-name t t)
+                  (error t))
+            (while (condition-case nil
+                       (progn
+                         (when (file-exists-p to-name)
+                           (delete-file to-name))
+                         (copy-file from-name to-name nil t)
+                         nil)
+                     (file-already-exists t))
+              ;; The file was somehow created by someone else between
+              ;; `delete-file' and `copy-file', so let's try again.
+              ;; rms says "I think there is also a possible race
+              ;; condition for making backup files" (emacs-devel 20070821).
+              nil)))
       ;; Reset the umask.
       (set-default-file-modes umask)))
   (and modes