From 6225bea261c5647477e76f19ca1f3741c548d56d Mon Sep 17 00:00:00 2001
From: chunhtai <47866232+chunhtai@users.noreply.github.com>
Date: Thu, 4 Aug 2022 10:21:06 -0700
Subject: [PATCH] Can call ChangeNotifier.hasListeners after disposed (#108931)

---
 .../lib/src/foundation/change_notifier.dart        |  7 +++----
 .../test/foundation/change_notifier_test.dart      | 14 ++++++++++++++
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/packages/flutter/lib/src/foundation/change_notifier.dart b/packages/flutter/lib/src/foundation/change_notifier.dart
index f79fb7b2da6..71c7fc230b9 100644
--- a/packages/flutter/lib/src/foundation/change_notifier.dart
+++ b/packages/flutter/lib/src/foundation/change_notifier.dart
@@ -170,11 +170,10 @@ class ChangeNotifier implements Listenable {
   /// [notifyListeners]; and similarly, by overriding [removeListener], checking
   /// if [hasListeners] is false after calling `super.removeListener()`, and if
   /// so, stopping that same work.
+  ///
+  /// This method returns false if [dispose] has been called.
   @protected
-  bool get hasListeners {
-    assert(ChangeNotifier.debugAssertNotDisposed(this));
-    return _count > 0;
-  }
+  bool get hasListeners => _count > 0;
 
   /// Register a closure to be called when the object changes.
   ///
diff --git a/packages/flutter/test/foundation/change_notifier_test.dart b/packages/flutter/test/foundation/change_notifier_test.dart
index cfdf4aa59f2..8ff4e29a89b 100644
--- a/packages/flutter/test/foundation/change_notifier_test.dart
+++ b/packages/flutter/test/foundation/change_notifier_test.dart
@@ -349,6 +349,20 @@ void main() {
     expect(error, isNull);
   });
 
+  test('Can check hasListener on a disposed ChangeNotifier', () {
+    final HasListenersTester<int> source = HasListenersTester<int>(0);
+    source.addListener(() { });
+    expect(source.testHasListeners, isTrue);
+    FlutterError? error;
+    try {
+      source.dispose();
+      expect(source.testHasListeners, isFalse);
+    } on FlutterError catch (e) {
+      error = e;
+    }
+    expect(error, isNull);
+  });
+
   test('Value notifier', () {
     final ValueNotifier<double> notifier = ValueNotifier<double>(2.0);