Fix infinite loop in vc-dir-mark-unmark

* lisp/vc/vc-dir.el (vc-dir-mark-unmark): Prevent from getting
stuck on the same line in an infinite loop.  (Bug#24017)

1 files changed, 6 insertions, 2 deletions

diff --git a/lisp/vc/vc-dir.el b/lisp/vc/vc-dir.el
index 41c44e2c24a..52c7d3e658b 100644
--- a/lisp/vc/vc-dir.el
+++ b/lisp/vc/vc-dir.el
@@ -554,11 +554,15 @@ If a prefix argument is given, move by that many lines."
 
 (defun vc-dir-mark-unmark (mark-unmark-function)
   (if (use-region-p)
-      (let (;; (firstl (line-number-at-pos (region-beginning)))
+      (let ((processed-line nil)
             (lastl (line-number-at-pos (region-end))))
         (save-excursion
           (goto-char (region-beginning))
-          (while (<= (line-number-at-pos) lastl)
+          (while (and (<= (line-number-at-pos) lastl)
+                      ;; We make sure to not get stuck processing the
+                      ;; same line in an infinite loop.
+                      (not (eq processed-line (line-number-at-pos))))
+            (setq processed-line (line-number-at-pos))
             (condition-case nil
                 (funcall mark-unmark-function)
               ;; `vc-dir-mark-file' signals an error if we try marking