master 9a2c723f1bc 3/3: VC: Allow `vc-default-revert' (and CVS) to revert a missing file

[Dmitry Gutov]

branch: master
commit 9a2c723f1bc592fdd28763c8ec67129c5c5d91f1
Author: Olivier Certner <olce.emacs@certner.fr>
Commit: Dmitry Gutov <dmitry@gutov.dev>

    VC: Allow `vc-default-revert' (and CVS) to revert a missing file
    
    * lisp/vc/vc.el (vc-default-revert): Fix reverting a missing file case
    by not trying to create a backup through `copy-file'.  Notably impacts
    CVS, where `vc-cvs-revert' calls `vc-default-revert'.
---
 lisp/vc/vc.el | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lisp/vc/vc.el b/lisp/vc/vc.el
index 32b0d5d7556..91d3f6f70d3 100644
--- a/lisp/vc/vc.el
+++ b/lisp/vc/vc.el
@@ -3604,7 +3604,8 @@ to provide the `find-revision' operation instead."
           (file-buffer (or (get-file-buffer file) (current-buffer))))
       (message "Checking out %s..." file)
       (let ((failed t)
-            (backup-name (car (find-backup-file-name file))))
+            (backup-name (when (file-exists-p file)
+                           (car (find-backup-file-name file)))))
         (when backup-name
           (copy-file file backup-name 'ok-if-already-exists 'keep-date)
           (unless (file-writable-p file)