[release/10.0] Fix ComponentStatePersistenceManager iteration to prevent AntiforgeryValidationException in Blazor WASM (#63694)

* Initial plan * Fix ComponentStatePersistenceManager to iterate backwards in InferRenderModes Co-authored-by: javiercn <6995051+javiercn@users.noreply.github.com> * Add unit test for ComponentStatePersistenceManager callback removal during iteration Co-authored-by: javiercn <6995051+javiercn@users.noreply.github.com> --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: javiercn <6995051+javiercn@users.noreply.github.com>

Author: 3 people

src/Components/Components/src/PersistentState/ComponentStatePersistenceManager.cs

@@ -172,7 +172,13 @@ public void SetPlatformRenderMode(IComponentRenderMode renderMode)
 
  private void InferRenderModes(Renderer renderer)
  {
- for (var i = 0; i < _registeredCallbacks.Count; i++)
+ // We are iterating backwards to allow the callbacks to remove themselves from the list.
+ // Otherwise, we would have to make a copy of the list to avoid running into situations
+ // where we don't run all the callbacks because the count of the list changed while we
+ // were iterating over it.
+ // It is not allowed to register a callback while we are persisting the state, so we don't
+ // need to worry about new callbacks being added to the list.
+ for (var i = _registeredCallbacks.Count - 1; i >= 0; i--)
  {
  var registration = _registeredCallbacks[i];
  if (registration.RenderMode != null)

src/Components/Components/test/PersistentState/ComponentStatePersistenceManagerTest.cs

@@ -353,6 +353,53 @@ public async Task PersistStateAsync_InvokesAllCallbacksEvenIfACallbackIsRemovedA
  Assert.Equal(4, executionSequence.Count);
  }
 
+ [Fact]
+ public async Task PersistStateAsync_InvokesAllCallbacksWhenFirstCallbackUnregistersItself()
+ {
+ // Arrange
+ var state = new Dictionary<string, byte[]>();
+ var store = new TestStore(state);
+ var persistenceManager = new ComponentStatePersistenceManager(
+ NullLogger<ComponentStatePersistenceManager>.Instance,
+ CreateServiceProvider());
+ var renderer = new TestRenderer();
+
+ var executionSequence = new List<int>();
+
+ // Register the first callback that will unregister itself - this is the key test case
+ // where the first callback removes itself from the collection during iteration
+ PersistingComponentStateSubscription firstSubscription = default;
+ firstSubscription = persistenceManager.State.RegisterOnPersisting(() =>
+ {
+ executionSequence.Add(1);
+ firstSubscription.Dispose(); // Remove itself from the collection
+ return Task.CompletedTask;
+ }, new TestRenderMode());
+
+ // Register additional callbacks to ensure they still get executed
+ persistenceManager.State.RegisterOnPersisting(() =>
+ {
+ executionSequence.Add(2);
+ return Task.CompletedTask;
+ }, new TestRenderMode());
+
+ persistenceManager.State.RegisterOnPersisting(() =>
+ {
+ executionSequence.Add(3);
+ return Task.CompletedTask;
+ }, new TestRenderMode());
+
+ // Act
+ await persistenceManager.PersistStateAsync(store, renderer);
+
+ // Assert
+ // All callbacks should be executed even though the first one removed itself
+ Assert.Contains(1, executionSequence);
+ Assert.Contains(2, executionSequence);
+ Assert.Contains(3, executionSequence);
+ Assert.Equal(3, executionSequence.Count);
+ }
+
  [Fact]
  public async Task RestoreStateAsync_ValidatesOnlySupportUpdatesWhenRestoreContextValueUpdate()
  {