Fix multiple root ProviderScopes

fixes #3124
fixes #3118

packages/flutter_riverpod/CHANGELOG.md

@@ -1,3 +1,7 @@
+## Unreleased fix
+
+Fix exceptions when using multiple root `ProviderContainers`/`ProviderScopes`.
+
 ## 2.4.7 - 2023-11-20
 
 - Fix `ProviderObserver.didUpdateProvider` being called with an incorrect

packages/flutter_riverpod/lib/src/framework.dart

@@ -8,7 +8,7 @@ import 'package:meta/meta.dart';
 
 import 'internals.dart';
 
-/// {@template riverpod.providerscope}
+/// {@template riverpod.provider_scope}
 /// A widget that stores the state of providers.
 ///
 /// All Flutter applications using Riverpod must contain a [ProviderScope] at
@@ -78,7 +78,7 @@ import 'internals.dart';
 /// {@endtemplate}
 @sealed
 class ProviderScope extends StatefulWidget {
-  /// {@macro riverpod.providerscope}
+  /// {@macro riverpod.provider_scope}
   const ProviderScope({
     super.key,
     this.overrides = const [],
@@ -305,7 +305,7 @@ class _UncontrolledProviderScopeElement extends InheritedElement {
       debugCanModifyProviders ??= _debugCanModifyProviders;
     }
 
-    flutterVsyncs.add(_flutterVsync);
+    _containerOf(widget).scheduler.flutterVsyncs.add(_flutterVsync);
     super.mount(parent, newSlot);
   }
 
@@ -380,7 +380,7 @@ To fix this problem, you have one of two solutions:
       debugCanModifyProviders = null;
     }
 
-    flutterVsyncs.remove(_flutterVsync);
+    _containerOf(widget).scheduler.flutterVsyncs.remove(_flutterVsync);
 
     super.unmount();
   }

packages/flutter_riverpod/test/framework_test.dart

@@ -47,6 +47,48 @@ void main() {
     );
   });
 
+  testWidgets('Supports multiple ProviderScope roots in the same tree',
+      (tester) async {
+    final a = StateProvider((_) => 0);
+    final b = Provider((ref) => ref.watch(a));
+
+    await tester.pumpWidget(
+      // No root scope. We want to test cases where there are multiple roots
+      Column(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          for (var i = 0; i < 2; i++)
+            SizedBox(
+              width: 100,
+              height: 100,
+              child: ProviderScope(
+                child: Consumer(
+                  builder: (context, ref, _) {
+                    ref.watch(a);
+                    ref.watch(b);
+                    return Container();
+                  },
+                ),
+              ),
+            ),
+        ],
+      ),
+    );
+
+    final containers = tester.allElements
+        .where((e) => e.widget is Consumer)
+        .map(ProviderScope.containerOf)
+        .toList();
+
+    expect(containers, hasLength(2));
+
+    for (final container in containers) {
+      container.read(a.notifier).state++;
+    }
+
+    await tester.pump();
+  });
+
   testWidgets('ref.invalidate can invalidate a family', (tester) async {
     final listener = Listener<String>();
     final listener2 = Listener<String>();
@@ -284,8 +326,9 @@ void main() {
   testWidgets('UncontrolledProviderScope gracefully handles vsync',
       (tester) async {
     final container = createContainer();
+    final container2 = createContainer(parent: container);
 
-    expect(flutterVsyncs, isEmpty);
+    expect(container.scheduler.flutterVsyncs, isEmpty);
 
     await tester.pumpWidget(
       UncontrolledProviderScope(
@@ -294,18 +337,21 @@ void main() {
       ),
     );
 
-    expect(flutterVsyncs, hasLength(1));
+    expect(container.scheduler.flutterVsyncs, hasLength(1));
+    expect(container2.scheduler.flutterVsyncs, isEmpty);
 
     await tester.pumpWidget(
       UncontrolledProviderScope(
         container: container,
-        child: ProviderScope(
+        child: UncontrolledProviderScope(
+          container: container2,
           child: Container(),
         ),
       ),
     );
 
-    expect(flutterVsyncs, hasLength(2));
+    expect(container.scheduler.flutterVsyncs, hasLength(1));
+    expect(container2.scheduler.flutterVsyncs, hasLength(1));
 
     await tester.pumpWidget(
       UncontrolledProviderScope(
@@ -314,11 +360,13 @@ void main() {
       ),
     );
 
-    expect(flutterVsyncs, hasLength(1));
+    expect(container.scheduler.flutterVsyncs, hasLength(1));
+    expect(container2.scheduler.flutterVsyncs, isEmpty);
 
     await tester.pumpWidget(Container());
 
-    expect(flutterVsyncs, isEmpty);
+    expect(container.scheduler.flutterVsyncs, isEmpty);
+    expect(container2.scheduler.flutterVsyncs, isEmpty);
   });
 
   testWidgets('When there are multiple vsyncs, rebuild providers only once',
@@ -625,7 +673,7 @@ void main() {
     await tester.pumpWidget(
       ProviderScope(
         overrides: [
-          provider.overrideWithValue('rootoverride'),
+          provider.overrideWithValue('rootOverride'),
         ],
         child: ProviderScope(
           child: Consumer(
@@ -643,7 +691,7 @@ void main() {
     );
 
     expect(find.text('root root2'), findsNothing);
-    expect(find.text('rootoverride root2'), findsOneWidget);
+    expect(find.text('rootOverride root2'), findsOneWidget);
   });
 
   testWidgets('ProviderScope throws if ancestorOwner changed', (tester) async {

packages/hooks_riverpod/CHANGELOG.md

@@ -1,3 +1,7 @@
+## Unreleased fix
+
+Fix exceptions when using multiple root `ProviderContainers`/`ProviderScopes`.
+
 ## 2.4.7 - 2023-11-20
 
 - Fix `ProviderObserver.didUpdateProvider` being called with an incorrect

packages/riverpod/CHANGELOG.md

@@ -1,3 +1,7 @@
+## Unreleased fix
+
+Fix exceptions when using multiple root `ProviderContainers`/`ProviderScopes`.
+
 ## 2.4.7 - 2023-11-20
 
 - Fix `ProviderObserver.didUpdateProvider` being called with an incorrect

packages/riverpod/lib/riverpod.dart

@@ -24,9 +24,8 @@ export 'src/common.dart' hide AsyncTransition;
 
 export 'src/framework.dart'
     hide
+        ProviderScheduler,
         debugCanModifyProviders,
-        vsync,
-        flutterVsyncs,
         Vsync,
         ValueProviderElement,
         ValueProvider,

packages/riverpod/lib/src/framework/auto_dispose.dart

@@ -37,7 +37,7 @@ mixin AutoDisposeProviderElementMixin<State> on ProviderElementBase<State>
 
     // ignore: deprecated_member_use_from_same_package
     if (!maintainState && !hasListeners && (links == null || links.isEmpty)) {
-      _container._scheduler.scheduleProviderDispose(this);
+      _container.scheduler.scheduleProviderDispose(this);
     }
   }
 

packages/riverpod/lib/src/framework/container.dart

@@ -157,8 +157,8 @@ class ProviderContainer implements Node {
   void Function(void Function() task)? vsyncOverride;
 
   /// The object that handles when providers are refreshed and disposed.
-  late final _ProviderScheduler _scheduler =
-      _parent?._scheduler ?? _ProviderScheduler();
+  @internal
+  late final ProviderScheduler scheduler = ProviderScheduler();
 
   /// How deep this [ProviderContainer] is in the graph of containers.
   ///
@@ -214,7 +214,13 @@ class ProviderContainer implements Node {
 
   /// Awaits for providers to rebuild/be disposed and for listeners to be notified.
   Future<void> pump() async {
-    return _scheduler.pendingFuture;
+    final a = scheduler.pendingFuture;
+    final b = _parent?.scheduler.pendingFuture;
+
+    await Future.wait<void>([
+      if (a != null) a,
+      if (b != null) b,
+    ]);
   }
 
   /// Reads a provider without listening to it and returns the currently
@@ -630,7 +636,7 @@ final b = Provider((ref) => ref.watch(a), dependencies: [a]);
       element.dispose();
     }
 
-    if (_root == null) _scheduler.dispose();
+    if (_root == null) scheduler.dispose();
   }
 
   /// Traverse the [ProviderElementBase]s associated with this [ProviderContainer].

packages/riverpod/lib/src/framework/element.dart

@@ -296,7 +296,7 @@ abstract class ProviderElementBase<State> implements Ref<State>, Node {
 
     _mustRecomputeState = true;
     runOnDispose();
-    _container._scheduler.scheduleProviderRefresh(this);
+    _container.scheduler.scheduleProviderRefresh(this);
 
     // We don't call this._markDependencyMayHaveChanged here because we voluntarily
     // do not want to set the _dependencyMayHaveChanged flag to true.

packages/riverpod/lib/src/framework/scheduler.dart

@@ -5,48 +5,49 @@ part of '../framework.dart';
 @internal
 typedef Vsync = void Function(void Function());
 
-/// A way to override [vsync], used by Flutter to synchronize a container
-/// with the widget tree.
-@internal
-final flutterVsyncs = <Vsync>{};
-
 void _defaultVsync(void Function() task) {
   Future(task);
 }
 
-/// A function that controls the refresh rate of providers.
-///
-/// Defaults to refreshing providers at the end of the next event-loop.
-@internal
-void Function(void Function()) get vsync {
-  if (flutterVsyncs.isNotEmpty) {
-    // Notify all InheritedWidgets of a possible rebuild.
-    // At the same time, we only execute the task once, in whichever
-    // InheritedWidget that rebuilds first.
-    return (task) {
-      var invoked = false;
-      void invoke() {
-        if (invoked) return;
-        invoked = true;
-        task();
-      }
-
-      for (final flutterVsync in flutterVsyncs) {
-        flutterVsync(invoke);
-      }
-    };
-  }
-
-  return _defaultVsync;
-}
-
 /// The object that handles when providers are refreshed and disposed.
 ///
 /// Providers are typically refreshed at the end of the frame where they
 /// notified that they wanted to rebuild.
 ///
 /// Providers are disposed if they spent at least one full frame without any listener.
-class _ProviderScheduler {
+@internal
+class ProviderScheduler {
+  /// A way to override [vsync], used by Flutter to synchronize a container
+  /// with the widget tree.
+  @internal
+  final flutterVsyncs = <Vsync>{};
+
+  /// A function that controls the refresh rate of providers.
+  ///
+  /// Defaults to refreshing providers at the end of the next event-loop.
+  @internal
+  void Function(void Function()) get vsync {
+    if (flutterVsyncs.isNotEmpty) {
+      // Notify all InheritedWidgets of a possible rebuild.
+      // At the same time, we only execute the task once, in whichever
+      // InheritedWidget that rebuilds first.
+      return (task) {
+        var invoked = false;
+        void invoke() {
+          if (invoked) return;
+          invoked = true;
+          task();
+        }
+
+        for (final flutterVsync in flutterVsyncs) {
+          flutterVsync(invoke);
+        }
+      };
+    }
+
+    return _defaultVsync;
+  }
+
   final _stateToDispose = <AutoDisposeProviderElementMixin<Object?>>[];
   final _stateToRefresh = <ProviderElementBase<Object?>>[];
 

packages/riverpod/test/framework/provider_container_test.dart

@@ -399,7 +399,7 @@ void main() {
 
     group('.pump', () {
       test(
-          'waits for providers to rebuild or get disposed, no matter from which container they are associated in the graph',
+          'Waits for providers associated with this container and its parents to rebuild',
           () async {
         final dep = StateProvider((ref) => 0);
         final a = Provider((ref) => ref.watch(dep));
@@ -417,7 +417,7 @@ void main() {
         verifyOnly(bListener, bListener(null, 0));
 
         root.read(dep.notifier).state++;
-        await root.pump();
+        await scoped.pump();
 
         verifyOnly(aListener, aListener(0, 1));
         verifyOnly(bListener, bListener(0, 1));