accepts_input_at rejects buffer-less surfaces

src/ifs/wl_surface.rs

@@ -318,7 +318,7 @@ pub struct WlSurface {
     pub content_type: Cell<Option<ContentType>>,
     pub drm_feedback: CopyHashMap<ZwpLinuxDmabufFeedbackV1Id, Rc<ZwpLinuxDmabufFeedbackV1>>,
     syncobj_surface: CloneCell<Option<Rc<WpLinuxDrmSyncobjSurfaceV1>>>,
-    destroyed: Cell<bool>,
+    pub destroyed: Cell<bool>,
     commit_timeline: CommitTimeline,
     alpha_modifier: CloneCell<Option<Rc<WpAlphaModifierSurfaceV1>>>,
     alpha: Cell<Option<f32>>,
@@ -1019,6 +1019,7 @@ impl WlSurfaceRequestHandler for WlSurface {
         self.unset_dnd_icons();
         self.unset_cursors();
         self.ext.get().on_surface_destroy()?;
+        self.destroyed.set(true);
         self.destroy_node();
         {
             let mut children = self.children.borrow_mut();
@@ -1029,6 +1030,19 @@ impl WlSurfaceRequestHandler for WlSurface {
             }
             *children = None;
         }
+        // Capture a close-animation snapshot if the client is destroying the
+        // surface while it still has a buffer (i.e. without a clean null-attach
+        // commit first — typical for crash/disconnect paths).
+        if self.buffer.is_some()
+            && let Some(tl) = self.toplevel.get()
+            && let Some(snap) = crate::animation::capture_snapshot(&self.client.state, &tl)
+        {
+            self.client
+                .state
+                .close_snapshots
+                .borrow_mut()
+                .push(Rc::new(snap));
+        }
         self.buffer.set(None);
         self.reset_shm_textures();
         if let Some(xwayland_serial) = self.xwayland_serial.get() {
@@ -1041,7 +1055,6 @@ impl WlSurfaceRequestHandler for WlSurface {
         self.client.remove_obj(self)?;
         self.idle_inhibitors.clear();
         self.constraints.take();
-        self.destroyed.set(true);
         Ok(())
     }
 
@@ -1238,8 +1251,24 @@ impl WlSurface {
         let mut buffer_changed = false;
         let mut old_raw_size = None;
         let (mut dx, mut dy) = mem::take(&mut pending.offset);
+        let mut buffer_presence_changed = false;
         if let Some(buffer_change) = pending.buffer.take() {
             buffer_changed = true;
+            buffer_presence_changed = buffer_change.is_some() != self.buffer.is_some();
+            // If the client just attached a null buffer to the main surface of
+            // a mapped toplevel, capture a snapshot before we drop the buffer
+            // so the close animation has something to render after teardown.
+            if buffer_change.is_none()
+                && self.buffer.is_some()
+                && let Some(tl) = self.toplevel.get()
+                && let Some(snap) = crate::animation::capture_snapshot(&self.client.state, &tl)
+            {
+                self.client
+                    .state
+                    .close_snapshots
+                    .borrow_mut()
+                    .push(Rc::new(snap));
+            }
             if let Some(buffer) = self.buffer.take() {
                 old_raw_size = Some(buffer.buffer.buf.rect);
             }
@@ -1408,6 +1437,16 @@ impl WlSurface {
             };
             self.is_opaque.set(is_opaque);
         }
+        if buffer_abs_pos_size_changed || buffer_presence_changed {
+            // Pointer focus depends on whether this surface accepts input.
+            // It just changed (size shrank/grew, or buffer went from null to
+            // non-null or vice versa — the latter happens when a client
+            // dismisses a subsurface by null-attaching while keeping its
+            // wp_viewport destination). Force a re-evaluation so the pointer
+            // stack doesn't keep a now-invisible surface focused until the
+            // next motion event.
+            self.client.state.tree_changed();
+        }
         let mut tearing_changed = false;
         if let Some(tearing) = pending.tearing.take()
             && self.tearing.replace(tearing) != tearing
@@ -1597,6 +1636,13 @@ impl WlSurface {
     }
 
     fn accepts_input_at(&self, mut x: i32, mut y: i32) -> bool {
+        // Per the wayland spec, a surface without a buffer is invisible and
+        // cannot receive input. Without this check, a client that null-buffers
+        // but keeps a wp_viewport destination set (as foot does for its
+        // fractional-scaling subsurfaces) would keep an invisible hit-rect.
+        if self.buffer.is_none() {
+            return false;
+        }
         let rect = self.buffer_abs_pos.get().at_point(0, 0);
         if !rect.contains(x, y) {
             return false;