Box the widget: Widget field of WidgetInstance (#3506)

Box the `pub widget: Box<Widget>` field of `WidgetInstance`

Author: Keavon

editor/src/dispatcher.rs

@@ -594,7 +594,7 @@ mod test {
 				if let FrontendMessage::UpdateDialogColumn1 { diff } = response {
 					if let DiffUpdate::Layout(sub_layout) = &diff[0].new_value {
 						if let LayoutGroup::Row { widgets } = &sub_layout.0[0] {
-							if let Widget::TextLabel(TextLabel { value, .. }) = &widgets[0].widget {
+							if let Widget::TextLabel(TextLabel { value, .. }) = &*widgets[0].widget {
 								print_problem_to_terminal_on_failure(value);
 							}
 						}

editor/src/messages/layout/layout_message_handler.rs

@@ -71,7 +71,7 @@ impl LayoutMessageHandler {
 							return Some((widget, widget_path));
 						}
 
-						if let Widget::PopoverButton(popover) = &widget.widget {
+						if let Widget::PopoverButton(popover) = &*widget.widget {
 							stack.extend(
 								popover
 									.popover_layout
@@ -97,7 +97,7 @@ impl LayoutMessageHandler {
 								return Some((cell, widget_path));
 							}
 
-							if let Widget::PopoverButton(popover) = &cell.widget {
+							if let Widget::PopoverButton(popover) = &*cell.widget {
 								stack.extend(
 									popover
 										.popover_layout
@@ -126,7 +126,7 @@ impl LayoutMessageHandler {
 			return;
 		};
 
-		match &mut widget_instance.widget {
+		match &mut *widget_instance.widget {
 			Widget::BreadcrumbTrailButtons(breadcrumb_trail_buttons) => {
 				let callback_message = match action {
 					WidgetValueAction::Commit => (breadcrumb_trail_buttons.on_commit.callback)(&()),

editor/src/messages/layout/utility_types/layout_widget.rs

@@ -229,13 +229,13 @@ impl<'a> Iterator for WidgetIter<'a> {
 			Some(first)
 		});
 
-		if let Some(item) = widget {
-			if let WidgetInstance { widget: Widget::PopoverButton(p), .. } = item {
-				self.stack.extend(p.popover_layout.0.iter());
+		if let Some(instance) = widget {
+			if let Widget::PopoverButton(popover_button) = &*instance.widget {
+				self.stack.extend(popover_button.popover_layout.0.iter());
 				return self.next();
 			}
 
-			return Some(item);
+			return Some(instance);
 		}
 
 		match self.stack.pop() {
@@ -279,13 +279,15 @@ impl<'a> Iterator for WidgetIterMut<'a> {
 			Some(first)
 		});
 
-		if let Some(widget) = widget {
-			if let WidgetInstance { widget: Widget::PopoverButton(p), .. } = widget {
-				self.stack.extend(p.popover_layout.0.iter_mut());
-				return self.next();
+		if let Some(instance) = widget {
+			// We have to check that we're not a popover and return first, then extract the popover with an unreachable else condition second, to satisfy the borrow checker.
+			// After Rust's Polonius is stable, we can reverse that order of steps to avoid the redundancy and unreachable statement.
+			if !matches!(*instance.widget, Widget::PopoverButton(_)) {
+				return Some(instance);
 			}
-
-			return Some(widget);
+			let Widget::PopoverButton(popover_button) = &mut *instance.widget else { unreachable!() };
+			self.stack.extend(popover_button.popover_layout.0.iter_mut());
+			return self.next();
 		}
 
 		match self.stack.pop() {
@@ -362,7 +364,7 @@ impl LayoutGroup {
 		};
 		let description = description.into();
 		for widget in &mut widgets {
-			let val = match &mut widget.widget {
+			let val = match &mut *widget.widget {
 				Widget::CheckboxInput(x) => &mut x.tooltip_description,
 				Widget::ColorInput(x) => &mut x.tooltip_description,
 				Widget::CurveInput(x) => &mut x.tooltip_description,
@@ -552,7 +554,7 @@ impl Diffable for LayoutGroup {
 pub struct WidgetInstance {
 	#[serde(rename = "widgetId")]
 	pub widget_id: WidgetId,
-	pub widget: Widget,
+	pub widget: Box<Widget>,
 }
 
 impl PartialEq for WidgetInstance {
@@ -566,7 +568,7 @@ impl WidgetInstance {
 	pub fn new(widget: Widget) -> Self {
 		Self {
 			widget_id: WidgetId(generate_uuid()),
-			widget,
+			widget: Box::new(widget),
 		}
 	}
 }
@@ -584,7 +586,7 @@ impl Diffable for WidgetInstance {
 		}
 
 		// Special handling for PopoverButton: recursively diff nested layout if only the layout changed
-		if let (Widget::PopoverButton(button1), Widget::PopoverButton(button2)) = (&mut self.widget, &new.widget) {
+		if let (Widget::PopoverButton(button1), Widget::PopoverButton(button2)) = (&mut *self.widget, &*new.widget) {
 			// Check if only the popover layout changed (all other fields are the same)
 			if self.widget_id == new.widget_id
 				&& button1.disabled == button2.disabled
@@ -614,7 +616,7 @@ impl Diffable for WidgetInstance {
 	}
 
 	fn collect_checkbox_ids(&self, layout_target: LayoutTarget, widget_path: &mut Vec<usize>, checkbox_map: &mut HashMap<CheckboxId, CheckboxId>) {
-		match &self.widget {
+		match &*self.widget {
 			Widget::CheckboxInput(checkbox) => {
 				// Compute stable ID based on position and insert mapping
 				let checkbox_id = checkbox.for_label;
@@ -644,7 +646,7 @@ impl Diffable for WidgetInstance {
 		self.widget_id = compute_widget_id(layout_target, widget_path, &self.widget);
 
 		// 2. Replace CheckboxIds if present
-		match &mut self.widget {
+		match &mut *self.widget {
 			Widget::CheckboxInput(checkbox) => {
 				let old_id = checkbox.for_label;
 				if let Some(&new_id) = checkbox_map.get(&old_id) {
@@ -744,7 +746,7 @@ impl DiffUpdate {
 		// Go through each widget to convert `ActionShortcut::Action` to `ActionShortcut::Shortcut` and append the key combination to the widget tooltip
 		let convert_tooltip = |widget_instance: &mut WidgetInstance| {
 			// Handle all the widgets that have tooltips
-			let tooltip_shortcut = match &mut widget_instance.widget {
+			let tooltip_shortcut = match &mut *widget_instance.widget {
 				Widget::BreadcrumbTrailButtons(widget) => widget.tooltip_shortcut.as_mut(),
 				Widget::CheckboxInput(widget) => widget.tooltip_shortcut.as_mut(),
 				Widget::ColorInput(widget) => widget.tooltip_shortcut.as_mut(),
@@ -775,7 +777,7 @@ impl DiffUpdate {
 			}
 
 			// Handle RadioInput separately because its tooltips are children of the widget
-			if let Widget::RadioInput(radio_input) = &mut widget_instance.widget {
+			if let Widget::RadioInput(radio_input) = &mut *widget_instance.widget {
 				for radio_entry_data in &mut radio_input.entries {
 					// Convert `ActionShortcut::Action` to `ActionShortcut::Shortcut`
 					if let Some(tooltip_shortcut) = radio_entry_data.tooltip_shortcut.as_mut() {
@@ -827,7 +829,7 @@ impl DiffUpdate {
 		};
 
 		// Apply shortcut conversions to all widgets that have menu lists
-		let convert_menu_lists = |widget_instance: &mut WidgetInstance| match &mut widget_instance.widget {
+		let convert_menu_lists = |widget_instance: &mut WidgetInstance| match &mut *widget_instance.widget {
 			Widget::DropdownInput(dropdown_input) => {
 				apply_action_shortcut_to_menu_lists(&mut dropdown_input.entries);
 				dropdown_input.entries_hash = hash_menu_list_entry_sections(&dropdown_input.entries);