Mention which exact file is already registered

* lisp/vc/vc.el (vc-register):
Mention which exact file is already registered (bug#44420).

diff --git a/lisp/vc/vc.el b/lisp/vc/vc.el
index 8def7da3776e275afa6c2a30262209fe1b2e23ce..32664bcd256dadeaff9434ccc80aa2da57197b82 100644 (file)
--- a/lisp/vc/vc.el
+++ b/lisp/vc/vc.el
@@ -1391,7 +1391,7 @@ first backend that could register the file is used."
        (unless fname
          (setq fname buffer-file-name))
        (when (vc-call-backend backend 'registered fname)
-         (error "This file is already registered"))
+         (error "This file is already registered: %s" fname))
        ;; Watch out for new buffers of size 0: the corresponding file
        ;; does not exist yet, even though buffer-modified-p is nil.
        (when bname