From 6e00e5e6e7c7bab6c2ba408b528e1bdee8f17239 Mon Sep 17 00:00:00 2001
From: Robert Mader <robert.mader@posteo.de>
Date: Fri, 16 Apr 2021 19:38:40 +0200
Subject: [PATCH] wayland/subsurface: Avoid placement ops for detached
 subsurfaces

If a subsurface first gets reordered and afterwards detached from
the parent before the parent surface got commited, we currently
would end up reattaching the subsurface to its previous parent.

While clients should avoid this behaviour, it's legit according
to the spec.

We already prevent similar cases where the subsurface is destroyed -
extend that check to detaching, which includes the destroy case.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1831>
---
 src/wayland/meta-wayland-subsurface.c | 16 ++++++++--------
 src/wayland/meta-wayland-subsurface.h |  2 +-
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/wayland/meta-wayland-subsurface.c b/src/wayland/meta-wayland-subsurface.c
index 27bd91f0c..d7f56b66e 100644
--- a/src/wayland/meta-wayland-subsurface.c
+++ b/src/wayland/meta-wayland-subsurface.c
@@ -355,11 +355,11 @@ is_valid_sibling (MetaWaylandSurface *surface,
 }
 
 static void
-subsurface_handle_pending_surface_destroyed (struct wl_listener *listener,
-                                             void               *data)
+subsurface_handle_pending_subsurface_destroyed (struct wl_listener *listener,
+                                                void               *data)
 {
   MetaWaylandSubsurfacePlacementOp *op =
-    wl_container_of (listener, op, surface_destroy_listener);
+    wl_container_of (listener, op, subsurface_destroy_listener);
 
   op->surface = NULL;
 }
@@ -378,7 +378,7 @@ void
 meta_wayland_subsurface_placement_op_free (MetaWaylandSubsurfacePlacementOp *op)
 {
   if (op->surface)
-    wl_list_remove (&op->surface_destroy_listener.link);
+    wl_list_remove (&op->subsurface_destroy_listener.link);
   if (op->sibling)
     wl_list_remove (&op->sibling_destroy_listener.link);
   g_free (op);
@@ -396,12 +396,12 @@ queue_subsurface_placement (MetaWaylandSurface             *surface,
   op->placement = placement;
   op->surface = surface;
   op->sibling = sibling;
-  op->surface_destroy_listener.notify =
-    subsurface_handle_pending_surface_destroyed;
+  op->subsurface_destroy_listener.notify =
+    subsurface_handle_pending_subsurface_destroyed;
   op->sibling_destroy_listener.notify =
     subsurface_handle_pending_sibling_destroyed;
-  wl_resource_add_destroy_listener (surface->resource,
-                                    &op->surface_destroy_listener);
+  wl_resource_add_destroy_listener (surface->wl_subsurface,
+                                    &op->subsurface_destroy_listener);
   wl_resource_add_destroy_listener (sibling->resource,
                                     &op->sibling_destroy_listener);
 
diff --git a/src/wayland/meta-wayland-subsurface.h b/src/wayland/meta-wayland-subsurface.h
index 7ea6bc5ae..45dbf8626 100644
--- a/src/wayland/meta-wayland-subsurface.h
+++ b/src/wayland/meta-wayland-subsurface.h
@@ -40,7 +40,7 @@ typedef struct
   MetaWaylandSubsurfacePlacement placement;
   MetaWaylandSurface *surface;
   MetaWaylandSurface *sibling;
-  struct wl_listener surface_destroy_listener;
+  struct wl_listener subsurface_destroy_listener;
   struct wl_listener sibling_destroy_listener;
 } MetaWaylandSubsurfacePlacementOp;