Notification fixups

CHANGELOG.md

@@ -24,6 +24,7 @@ You can find its changes [documented below](#070---2021-01-01).
 - Shell: IME API and macOS IME implementation ([#1619] by [@lord])
 - Scroll::content_must_fill and a few other new Scroll methods ([#1635] by [@cmyr])
 - New `TextBox` widget with IME integration ([#1636] by [@cmyr])
+- `Notification`s can be submitted while handling other `Notification`s ([#1640] by [@cmyr])
 - Added ListIter implementations for OrdMap ([#1641] by [@Lejero])
 
 ### Changed
@@ -39,6 +40,8 @@ You can find its changes [documented below](#070---2021-01-01).
 ### Removed
 
 ### Fixed
+- `Notification`s will not be delivered to the widget that sends them ([#1640] by [@cmyr])
+
 
 - Fixed docs of derived Lens ([#1523] by [@Maan2003])
 - Use correct fill rule when rendering SVG paths ([#1606] by [@SecondFlight])
@@ -638,6 +641,7 @@ Last release without a changelog :(
 [#1634]: https://github.com/linebender/druid/pull/1634
 [#1635]: https://github.com/linebender/druid/pull/1635
 [#1636]: https://github.com/linebender/druid/pull/1636
+[#1640]: https://github.com/linebender/druid/pull/1640
 [#1641]: https://github.com/linebender/druid/pull/1641
 [#1647]: https://github.com/linebender/druid/pull/1647
 

druid/src/core.rs

@@ -858,35 +858,33 @@ impl<T: Data, W: Widget<T>> WidgetPod<T, W> {
             notifications: parent_notifications,
             ..
         } = ctx;
-        let mut sentinal = VecDeque::new();
+        let self_id = self.id();
         let mut inner_ctx = EventCtx {
             state,
-            notifications: &mut sentinal,
+            notifications: parent_notifications,
             widget_state: &mut self.state,
             is_handled: false,
             is_root: false,
         };
 
-        for _ in 0..notifications.len() {
-            let notification = notifications.pop_front().unwrap();
-            let event = Event::Notification(notification);
-            self.inner.event(&mut inner_ctx, &event, data, env);
-            if inner_ctx.is_handled {
-                inner_ctx.is_handled = false;
-            } else if let Event::Notification(notification) = event {
-                // we will try again with the next parent
-                parent_notifications.push_back(notification);
+        for notification in notifications.drain(..) {
+            // skip notifications that were submitted by our child
+            if notification.source() != self_id {
+                let event = Event::Notification(notification);
+                self.inner.event(&mut inner_ctx, &event, data, env);
+                if inner_ctx.is_handled {
+                    inner_ctx.is_handled = false;
+                } else if let Event::Notification(notification) = event {
+                    // we will try again with the next parent
+                    inner_ctx.notifications.push_back(notification);
+                } else {
+                    // could be unchecked but we avoid unsafe in druid :shrug:
+                    unreachable!()
+                }
             } else {
-                unreachable!()
+                inner_ctx.notifications.push_back(notification);
             }
         }
-
-        if !inner_ctx.notifications.is_empty() {
-            warn!(
-                "A Notification was submitted while handling another \
-            notification; the submitted notification will be ignored."
-            );
-        }
     }
 
     /// Propagate a [`LifeCycle`] event.