fix: rebuild RearchElement when its widget updates (#164)

Fixes #163

packages/flutter_rearch/lib/src/widgets/consumer.dart

@@ -69,6 +69,15 @@ class _RearchElement extends ComponentElement {
     );
   }
 
+  // NOTE: for some reason, Flutter doesn't rebuild an Element automatically
+  // when its Widget changes; thus, we need to override this method.
+  // See https://github.com/GregoryConrad/rearch-dart/issues/163
+  @override
+  void update(RearchConsumer newWidget) {
+    super.update(newWidget);
+    rebuild(force: true);
+  }
+
   @override
   void deactivate() {
     for (final listener in deactivateListeners) {

packages/flutter_rearch/test/widgets_test.dart

@@ -0,0 +1,42 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_rearch/flutter_rearch.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:rearch/rearch.dart';
+
+void main() {
+  testWidgets('RearchConsumer rebuilds when constructor params change (#163)',
+      (tester) async {
+    await tester.pumpWidget(
+      const RearchBootstrapper(
+        child: MaterialApp(home: Scaffold(body: ParentConsumer())),
+      ),
+    );
+    expect(find.text('0'), findsOneWidget);
+    expect(find.text('1'), findsNothing);
+    await tester.tap(find.byType(TextButton));
+    await tester.pumpAndSettle();
+    expect(find.text('0'), findsNothing);
+    expect(find.text('1'), findsOneWidget);
+  });
+}
+
+class ParentConsumer extends RearchConsumer {
+  const ParentConsumer({super.key});
+  @override
+  Widget build(BuildContext context, WidgetHandle use) {
+    final value = use.data(0);
+    return TextButton(
+      onPressed: () => value.value++,
+      child: ChildConsumer(value.value),
+    );
+  }
+}
+
+class ChildConsumer extends RearchConsumer {
+  const ChildConsumer(this.i, {super.key});
+  final int i;
+  @override
+  Widget build(BuildContext context, WidgetHandle use) {
+    return Text('$i');
+  }
+}