master d727d3d: Check that the buffer in diff-buffer-with-file is visiting a file

[Lars Ingebrigtsen]

branch: master
commit d727d3dad649d1569a6babaf398439d101e282d4
Author: Daniel Martín <mardani29@yahoo.es>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Check that the buffer in diff-buffer-with-file is visiting a file
    
    * lisp/vc/diff.el (diff-buffer-with-file): Signal a specific error
    when the buffer passed to diff-buffer-with-file is not visiting a
    file (bug#43401).
---
 lisp/vc/diff.el | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lisp/vc/diff.el b/lisp/vc/diff.el
index 4698880..b7f17bf 100644
--- a/lisp/vc/diff.el
+++ b/lisp/vc/diff.el
@@ -258,6 +258,8 @@ This requires the external program `diff' to be in your 
`exec-path'."
   (interactive "bBuffer: ")
   (let ((buf (get-buffer (or buffer (current-buffer)))))
     (with-current-buffer (or (buffer-base-buffer buf) buf)
+      (unless buffer-file-name
+        (error "Buffer is not visiting a file"))
       (diff buffer-file-name (current-buffer) nil 'noasync))))
 
 ;;;###autoload