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

buffer visiting this file.

1 files changed, 5 insertions, 0 deletions

diff --git a/lisp/files.el b/lisp/files.el
index 309410ba992..b06e5a62f38 100644
--- 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))