Allow observer callback code to unsubscribe from action notifications (Fixes #84)

Author: mrpmorris

Docs/releases.md

@@ -1,5 +1,10 @@
 # Releases
 
+### New in 3.7
+ * Fix for ([#84](https://github.com/mrpmorris/Fluxor/issues/84) - 
+   Allow observer to unsubscribe from all subscriptions whilst executing
+   the callback from a previous subscription
+
 ### New in 3.6
  * Ensure synchronous effects are executed synchronously ([#76](https://github.com/mrpmorris/fluxor/issues/76)) -
      Reverts changes for [(#74) Endless loop redirects](https://github.com/mrpmorris/Fluxor/issues/74) as

Source/Fluxor/ActionSubscriber.cs

@@ -34,7 +34,8 @@ public void Notify(object action)
 					SubscriptionsForType
 						.Where(x => x.Key.IsAssignableFrom(action.GetType()))
 						.SelectMany(x => x.Value)
-						.Select(x => x.Callback);
+						.Select(x => x.Callback)
+						.ToArray();
 				foreach (Action<object> callback in callbacks)
 					callback(action);
 			});

Tests/Fluxor.UnitTests/ActionSubscriberTests/UnsubscribeFromAllActionsTests.cs

@@ -38,5 +38,24 @@ public void WhenExecuted_ThenOnlyUnsubscribesTheSpecifiedSubscriber()
 			Assert.Null(actionReceivedBySubscriber1);
 			Assert.Same(dispatchedAction, actionReceivedBySubscriber2);
 		}
+
+		[Fact]
+		public void WhenExecutedFromSubscriptionCallback_ThenDoesNotThrowAnError()
+		{
+			int executionCount = 0;
+			var subscriber = new object();
+			var dispatchedAction = new TestAction();
+
+			Subject.SubscribeToAction<TestAction>(subscriber, x =>
+			{
+				executionCount++;
+				Subject.UnsubscribeFromAllActions(subscriber);
+			});
+
+			Subject.Dispatch(dispatchedAction);
+			Subject.Dispatch(dispatchedAction);
+
+			Assert.Equal(1, executionCount);
+		}
 	}
 }