wayland: Avoid automatically decoupling source/offer after grab

In the case that DnD is performed and succeeds, we want to release
the grab early, and let the transfer IPC happen in the back. For
that to happen without a hitch, drag source and offer must be left
related to each other after undoing the grab, even though the default
ungrabbing code does that automatically (indirectly, by unsetting the
drag focus).

In these cases, we used to manually unset the current source, so
this decoupling was skipped. Notably, one missed case is X11 DnD,
so we might end up with the situation there that DnD did succeed,
transfer is ongoing, but the source and offer are already decoupled,
this confused the machinery and missed the finishing XdndFinished
to be emitted to the X11 drag source.

The prior commits prepared for this source/offer decoupling being
a manual operation, this commit avoids doing this automatically
when ungrabbing.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1720>

(cherry picked from commit 698fe3f1a98ae492335cfe718bc8818c14e813de)

1 files changed, 1 insertions, 5 deletions

diff --git a/src/wayland/meta-wayland-data-device.c b/src/wayland/meta-wayland-data-device.c
index 9311fd55d..e40a58c29 100644
--- a/src/wayland/meta-wayland-data-device.c
+++ b/src/wayland/meta-wayland-data-device.c
@@ -352,6 +352,7 @@ drag_grab_motion (MetaWaylandPointerGrab *grab,
 static void
 data_device_end_drag_grab (MetaWaylandDragGrab *drag_grab)
 {
+  meta_wayland_drag_grab_set_source (drag_grab, NULL);
   meta_wayland_drag_grab_set_focus (drag_grab, NULL);
 
   if (drag_grab->drag_origin)
@@ -366,8 +367,6 @@ data_device_end_drag_grab (MetaWaylandDragGrab *drag_grab)
       wl_list_remove (&drag_grab->drag_icon_listener.link);
     }
 
-  meta_wayland_drag_grab_set_source (drag_grab, NULL);
-
   if (drag_grab->feedback_actor)
     {
       clutter_actor_remove_all_children (drag_grab->feedback_actor);
@@ -448,9 +447,6 @@ drag_grab_button (MetaWaylandPointerGrab *grab,
           meta_wayland_data_source_has_target (source) &&
           meta_wayland_data_source_get_current_action (source))
         {
-          /* Detach the data source from the grab, it's meant to live longer */
-          meta_wayland_drag_grab_set_source (drag_grab, NULL);
-
           meta_wayland_surface_drag_dest_drop (drag_grab->drag_focus);
           meta_wayland_data_source_notify_drop_performed (source);