switch away from handles to refs that must be upgraded once

core/src/ui/mod.rs

@@ -7,7 +7,7 @@ use crate::{
 use image::DynamicImage;
 use std::{
     ops::{Index, IndexMut},
-    sync::mpsc::{Receiver, Sender, channel},
+    sync::mpsc::{Receiver, channel},
 };
 
 mod active;
@@ -38,7 +38,6 @@ pub struct Ui {
     pub root: Option<WidgetHandle>,
     old_root: Option<WidgetId>,
     recv: Receiver<WidgetId>,
-    send: Sender<WidgetId>,
     resized: bool,
 }
 
@@ -73,24 +72,20 @@ impl Ui {
         &self.widgets.data(id.id()).unwrap().label
     }
 
-    pub fn add_widget<W: Widget>(&mut self, w: W) -> WidgetHandle<W> {
-        WidgetHandle::new(self.widgets.add(w), self.send.clone())
-    }
-
     pub fn new() -> Self {
         Self::default()
     }
 
     pub fn get<I: IdLike>(&self, id: &I) -> Option<&I::Widget>
     where
-        I::Widget: Sized,
+        I::Widget: Sized + Widget,
     {
         self.widgets.get(id)
     }
 
     pub fn get_mut<I: IdLike>(&mut self, id: &I) -> Option<&mut I::Widget>
     where
-        I::Widget: Sized,
+        I::Widget: Sized + Widget,
     {
         self.widgets.get_mut(id)
     }
@@ -105,6 +100,20 @@ impl Ui {
     }
 
     pub fn update(&mut self, events: &mut dyn EventsLike) {
+        if !self.widgets.waiting.is_empty() {
+            let len = self.widgets.waiting.len();
+            let all: Vec<_> = self
+                .widgets
+                .waiting
+                .iter()
+                .map(|&w| format!("'{}' ({w:?})", self.label(w)))
+                .collect();
+            panic!(
+                "{len} widget(s) were never upgraded\n\
+                this is likely a memory leak; consider upgrading to strong if you plan on using it later\n\
+                weak widgets: {all:#?}"
+            );
+        }
         if self.root_changed() {
             DrawState::new(self, events).redraw_all();
             self.old_root = self.root.as_ref().map(|r| r.id());
@@ -169,7 +178,7 @@ impl Ui {
 
 impl<I: IdLike> Index<I> for Ui
 where
-    I::Widget: Sized,
+    I::Widget: Sized + Widget,
 {
     type Output = I::Widget;
 
@@ -180,7 +189,7 @@ where
 
 impl<I: IdLike> IndexMut<I> for Ui
 where
-    I::Widget: Sized,
+    I::Widget: Sized + Widget,
 {
     fn index_mut(&mut self, id: I) -> &mut Self::Output {
         self.get_mut(&id).unwrap()
@@ -191,7 +200,7 @@ impl Default for Ui {
     fn default() -> Self {
         let (send, recv) = channel();
         Self {
-            widgets: Default::default(),
+            widgets: Widgets::new(send),
             active: Default::default(),
             layers: Default::default(),
             masks: Default::default(),
@@ -201,7 +210,6 @@ impl Default for Ui {
             output_size: Vec2::ZERO,
             root: None,
             old_root: None,
-            send,
             recv,
             resized: false,
         }