Making sure that message with a pre-existing sagaId won't start new s…

…aga.

Fixes #2446
Adding failing acpt test for #2446

Making sure that a messages with a sagaid header won't start new sagas

Since they are targeted to a specific saga a new one should not be created
if it can't be found.

Fixes #2446

Adding test to verify that saga type should match

So that other sagas could be started

Conflicts:
	src/NServiceBus.Core/Sagas/SagaPersistenceBehavior.cs

src/NServiceBus.AcceptanceTests/NServiceBus.AcceptanceTests.csproj

@@ -172,6 +172,7 @@
     <Compile Include="Sagas\Issue_2044.cs" />
     <Compile Include="Sagas\When_doing_request_response_between_sagas.cs" />
     <Compile Include="Sagas\Issue_1819.cs" />
+    <Compile Include="Sagas\When_message_has_a_saga_id.cs" />
     <Compile Include="Sagas\When_sending_from_a_saga_timeout.cs" />
     <Compile Include="Sagas\When_sending_from_a_saga_handle.cs" />
     <Compile Include="Sagas\When_an_endpoint_replies_to_a_saga.cs" />

src/NServiceBus.AcceptanceTests/Sagas/When_message_has_a_saga_id.cs

@@ -0,0 +1,95 @@
+namespace NServiceBus.AcceptanceTests.Sagas
+{
+    using System;
+    using NServiceBus.AcceptanceTesting;
+    using NServiceBus.AcceptanceTests.EndpointTemplates;
+    using NServiceBus.Saga;
+    using NUnit.Framework;
+
+    public class When_message_has_a_saga_id : NServiceBusAcceptanceTest
+    {
+        [Test]
+        public void Should_not_start_a_new_saga_if_not_found()
+        {
+            var context = Scenario.Define<Context>()
+                .WithEndpoint<SagaEndpoint>(b => b.Given(bus =>
+                {
+                    var message = new MessageWithSagaId();
+
+                    bus.SetMessageHeader(message, Headers.SagaId, Guid.NewGuid().ToString());
+                    bus.SetMessageHeader(message, Headers.SagaType, typeof(MySaga).AssemblyQualifiedName);
+
+                    bus.SendLocal(message);
+                }))
+                .Done(c => c.NotFoundHandlerCalled && c.OtherSagaStarted)
+                .Run(TimeSpan.FromSeconds(15));
+
+            Assert.True(context.NotFoundHandlerCalled);
+            Assert.True(context.OtherSagaStarted);
+            Assert.False(context.MessageHandlerCalled);
+            Assert.False(context.TimeoutHandlerCalled);
+        }
+
+        class MySaga : Saga<MySaga.SagaData>, IAmStartedByMessages<MessageWithSagaId>,
+            IHandleTimeouts<MessageWithSagaId>,
+            IHandleSagaNotFound
+        {
+            public Context Context { get; set; }
+
+            public class SagaData : ContainSagaData
+            {
+            }
+
+            public void Handle(MessageWithSagaId message)
+            {
+                Context.MessageHandlerCalled = true;
+            }
+
+            public void Handle(object message)
+            {
+                Context.NotFoundHandlerCalled = true;
+            }
+
+            public void Timeout(MessageWithSagaId state)
+            {
+                Context.TimeoutHandlerCalled = true;
+            }
+        }
+
+        class MyOtherSaga : Saga<MyOtherSaga.SagaData>, IAmStartedByMessages<MessageWithSagaId>
+        {
+            public Context Context { get; set; }
+
+            public void Handle(MessageWithSagaId message)
+            {
+                Context.OtherSagaStarted = true;
+            }
+
+            public class SagaData : ContainSagaData
+            {
+            }
+
+        }
+
+
+        class Context : ScenarioContext
+        {
+            public bool NotFoundHandlerCalled { get; set; }
+            public bool MessageHandlerCalled { get; set; }
+            public bool TimeoutHandlerCalled { get; set; }
+            public bool OtherSagaStarted { get; set; }
+        }
+
+        public class SagaEndpoint : EndpointConfigurationBuilder
+        {
+            public SagaEndpoint()
+            {
+                EndpointSetup<DefaultServer>();
+            }
+        }
+
+        public class MessageWithSagaId : IMessage
+        {
+        }
+    }
+}

src/NServiceBus.AcceptanceTests/Sagas/When_sending_from_a_saga_timeout.cs

@@ -85,5 +85,4 @@ public class Saga1Timeout : IMessage
         {
         }
     }
-
 }

src/NServiceBus.Core/Sagas/SagaPersistenceBehavior.cs

@@ -44,7 +44,7 @@ public void Invoke(HandlerInvocationContext context, Action next)
             if (loadedEntity == null)
             {
                 //if this message are not allowed to start the saga
-                if (!Features.Sagas.ShouldMessageStartSaga(sagaInstanceState.SagaType, context.LogicalMessage.MessageType))
+                if (!IsAllowedToStartANewSaga(context, sagaInstanceState))
                 {
                     sagaInstanceState.MarkAsNotFound();
 
@@ -59,13 +59,11 @@ public void Invoke(HandlerInvocationContext context, Action next)
                 sagaInstanceState.AttachExistingEntity(loadedEntity);
             }
 
-
             if (IsTimeoutMessage(context.LogicalMessage))
             {
                 context.MessageHandler.Invocation = HandlerInvocationCache.InvokeTimeout;
             }
 
-
             next();
 
             if (sagaInstanceState.NotFound)
@@ -100,6 +98,25 @@ public void Invoke(HandlerInvocationContext context, Action next)
             }
         }
 
+        bool IsAllowedToStartANewSaga(HandlerInvocationContext context, ActiveSagaInstance sagaInstanceState)
+        {
+            string sagaType;
+
+            if (context.LogicalMessage.Headers.ContainsKey(Headers.SagaId) &&
+                context.LogicalMessage.Headers.TryGetValue(Headers.SagaType, out sagaType))
+            {
+                //we want to move away from the assembly fully qualified name since that will break if you move sagas
+                // between assemblies. We use the fullname instead which is enough to identify the saga
+                if (sagaType.StartsWith(sagaInstanceState.SagaType.FullName))
+                {
+                    //so now we have a saga id for this saga and if we can't find it we shouldn't start a new one
+                    return false;
+                }
+            }
+
+            return Features.Sagas.ShouldMessageStartSaga(sagaInstanceState.SagaType, context.LogicalMessage.MessageType);
+        }
+
         void InvokeSagaNotFoundHandlers()
         {
             logger.InfoFormat("Could not find a saga for the message type {0}. Going to invoke SagaNotFoundHandlers.", currentContext.LogicalMessage.MessageType.FullName);