(set-visited-file-name): Query if there's already another

buffer visiting this file.

diff --git a/lisp/files.el b/lisp/files.el
index 309410ba9923f080f8c1c4633ef75ab14d72ef67..b06e5a62f3851e00fcc41b3bc6a7a10648327923 100644 (file)
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -1422,6 +1422,11 @@ if you wish to pass an empty string as the argument."
          (setq truename (file-truename filename))
          (if find-file-visit-truename
              (setq filename truename))))
+    (let ((buffer (find-buffer-visiting filename)))
+      (and buffer (not (eq buffer (current-buffer)))
+          (not (y-or-n-p (message "A buffer is visiting %s; proceed? "
+                                  filename)))
+          (error "Aborted")))
     (or (equal filename buffer-file-name)
        (progn
          (and filename (lock-buffer filename))