From: Po Lu <luangruo@yahoo.com>
Date: Mon, 6 Jun 2022 04:48:40 +0000 (+0800)
Subject: Signal an error XdndSelection was lost during drag-and-drop
X-Git-Tag: emacs-29.0.90~1910^2~199
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=31bc62b6adeee5aa1539b1b527f52b85ea153d26;p=emacs.git

Signal an error XdndSelection was lost during drag-and-drop

* src/xselect.c (x_handle_selection_clear): Signal an error if
ownership of XdndSelection was lost during drag-and-drop.
---

diff --git a/src/xselect.c b/src/xselect.c
index 6e693c25884..b920540620b 100644
--- a/src/xselect.c
+++ b/src/xselect.c
@@ -928,6 +928,12 @@ x_handle_selection_clear (struct selection_input_event *event)
   /* Run the `x-lost-selection-functions' abnormal hook.  */
   CALLN (Frun_hook_with_args, Qx_lost_selection_functions, selection_symbol);
 
+  /* If Emacs lost ownership of XdndSelection during drag-and-drop,
+     there is no point in continuing the drag-and-drop session.  */
+  if (x_dnd_in_progress
+      && EQ (selection_symbol, QXdndSelection))
+    error ("Lost ownership of XdndSelection");
+
   redisplay_preserve_echo_area (20);
 }