vc-revert-file: Support reverting directories

* lisp/vc/vc.el (vc-revert-file): Support reverting directories
by calling vc-responsible-backend instead of vc-backend when
FILE is a directory (bug#37310, bug#43464).  Based on an
approach by Dmitry Gutov <dmitry@gutov.dev>.
(vc-rename-file): Add a FIXME to support reverting directories.
* etc/NEWS: Document the new functionality.

2 files changed, 21 insertions, 3 deletions

diff --git a/etc/NEWS b/etc/NEWS
index a0d81608103..12d7bd4f41f 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1161,6 +1161,10 @@ cloning, or prompts for that, too.
 When the argument is non-nil, the function switches to a buffer visiting
 the directory into which the repository was cloned.
 
+---
+*** C-x v u ('vc-revert') now works on directories listed in VC-Dir.
+Reverting a directory means reverting changes to all files inside it.
+
 ** Package
 
 +++
diff --git a/lisp/vc/vc.el b/lisp/vc/vc.el
index 551a053b9a8..d66f95578fa 100644
--- a/lisp/vc/vc.el
+++ b/lisp/vc/vc.el
@@ -3381,14 +3381,19 @@ its name; otherwise return nil."
           backup-file)))))
 
 (defun vc-revert-file (file)
-  "Revert FILE back to the repository working revision it was based on."
+  "Revert FILE back to the repository working revision it was based on.
+If FILE is a directory, revert all files inside that directory."
   (with-vc-properties
    (list file)
-   (let ((backup-file (vc-version-backup-file file)))
+   (let* ((dir (file-directory-p file))
+          (backup-file (and (not dir) (vc-version-backup-file file))))
      (when backup-file
        (copy-file backup-file file 'ok-if-already-exists)
        (vc-delete-automatic-version-backups file))
-     (vc-call revert file backup-file))
+     (vc-call-backend (if dir
+                          (vc-responsible-backend file)
+                        (vc-backend file))
+                      'revert file backup-file))
    `((vc-state . up-to-date)
      (vc-checkout-time . ,(file-attribute-modification-time
                            (file-attributes file)))))
@@ -3542,6 +3547,15 @@ buffer's file name if it's under version control."
   "Rename file OLD to NEW in both work area and repository.
 If called interactively, read OLD and NEW, defaulting OLD to the
 current buffer's file name if it's under version control."
+  ;; FIXME: Support renaming whole directories.
+  ;; The use of `vc-call' will need to change to something like
+  ;;
+  ;;     (vc-call-backend (if dir
+  ;;                          (vc-responsible-backend file)
+  ;;                        (vc-backend file))
+  ;;                      'rename-file old new)
+  ;;
+  ;; as was done in `vc-revert-file'; see bug#43464.  --spwhitton
   (interactive (list (read-file-name "VC rename file: " nil
                                      (when (vc-backend buffer-file-name)
                                        buffer-file-name) t)