wayland: Cancel selection data sources that are set while unfocusedwip/carlosg/cancel-unfocused-sources

If a client is naive enough to assume that it can set the selection while
it has got no surfaces, mutter will simply ignore the request and leave
the selection unchanged.

This is good and the expected behavior, however the poor client that did
this will enter in an inconsistent state where it "claimed" the selection,
but nobody told it that the wl_data_source is not current.

So, when the client is focused the next time, it will receive wl_data_offers
as usual, but it will still think all the time that it is owning the
selection. In the case of GTK, that takes client-side shortcuts, so any
attempted paste will still bring back the client-side aborted selection.

To fix this, cancel the selection right away if it happened while unfocused,
the client will be able to undo its own failed selection, and not assume
that future offers are its own.

Fixes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1469

3 files changed, 15 insertions, 3 deletions

diff --git a/src/wayland/meta-wayland-data-device-primary-legacy.c b/src/wayland/meta-wayland-data-device-primary-legacy.c
index 26d432357..684247e04 100644
--- a/src/wayland/meta-wayland-data-device-primary-legacy.c
+++ b/src/wayland/meta-wayland-data-device-primary-legacy.c
@@ -172,7 +172,11 @@ primary_device_set_selection (struct wl_client   *client,
 
   if (wl_resource_get_client (resource) !=
       meta_wayland_keyboard_get_focus_client (seat->keyboard))
-    return;
+    {
+      if (source)
+        meta_wayland_data_source_cancel (source);
+      return;
+    }
 
   meta_wayland_data_device_primary_legacy_set_selection (data_device, source, serial);
 }
diff --git a/src/wayland/meta-wayland-data-device-primary.c b/src/wayland/meta-wayland-data-device-primary.c
index ef1c5d964..9592e8f77 100644
--- a/src/wayland/meta-wayland-data-device-primary.c
+++ b/src/wayland/meta-wayland-data-device-primary.c
@@ -172,7 +172,11 @@ primary_device_set_selection (struct wl_client   *client,
 
   if (wl_resource_get_client (resource) !=
       meta_wayland_keyboard_get_focus_client (seat->keyboard))
-    return;
+    {
+      if (source)
+        meta_wayland_data_source_cancel (source);
+      return;
+    }
 
   meta_wayland_data_device_primary_set_selection (data_device, source, serial);
 }
diff --git a/src/wayland/meta-wayland-data-device.c b/src/wayland/meta-wayland-data-device.c
index 3e54cfa3c..61b4435d4 100644
--- a/src/wayland/meta-wayland-data-device.c
+++ b/src/wayland/meta-wayland-data-device.c
@@ -938,7 +938,11 @@ data_device_set_selection (struct wl_client *client,
 
   if (wl_resource_get_client (resource) !=
       meta_wayland_keyboard_get_focus_client (seat->keyboard))
-    return;
+    {
+      if (source)
+        meta_wayland_data_source_cancel (source);
+      return;
+    }
 
   /* FIXME: Store serial and check against incoming serial here. */
   meta_wayland_data_device_set_selection (data_device, source, serial);