Do not start new PM instance on :continue

lib/commanded/process_managers/process_manager_instance.ex

@@ -39,6 +39,13 @@ defmodule Commanded.ProcessManagers.ProcessManagerInstance do
     {:ok, state}
   end
 
+  @doc """
+  Checks whether or not the process manager has already processed events
+  """
+  def new?(process_manager) do
+    GenServer.call(process_manager, :new?)
+  end
+
   @doc """
   Handle the given event by delegating to the process manager module
   """
@@ -75,6 +82,11 @@ defmodule Commanded.ProcessManagers.ProcessManagerInstance do
     {:reply, process_state, state}
   end
 
+  @doc false
+  def handle_call(:new?, _from, %ProcessManagerInstance{last_seen_event: last_seen_event} = state) do
+    {:reply, is_nil(last_seen_event), state}
+  end
+
   @doc """
   Attempt to fetch intial process state from snapshot storage
   """

lib/commanded/process_managers/process_router.ex

@@ -235,7 +235,14 @@ defmodule Commanded.ProcessManagers.ProcessRouter do
         |> Enum.reduce(state, fn (process_uuid, state) ->
           {process_instance, state} = continue_process_manager(process_uuid, state)
 
-          delegate_event(process_instance, event, state)
+          case ProcessManagerInstance.new?(process_instance) do
+            false -> delegate_event(process_instance, event, state)
+            true ->
+              Logger.debug(fn -> describe(state) <> " is not interested in event: #{inspect event_number} (#{inspect stream_id}@#{inspect stream_version})" end)
+              stop_process_manager(process_uuid, state)
+
+              ack_and_continue(event, state)
+          end
         end)
 
       {:stop, process_uuid} ->

test/process_managers/process_manager_routing_test.exs

@@ -8,6 +8,7 @@ defmodule Commanded.ProcessManagers.ProcessManagerRoutingTest do
   alias Commanded.ExampleDomain.BankAccount.Commands.OpenAccount
   alias Commanded.ExampleDomain.BankAccount.Events.{MoneyDeposited,MoneyWithdrawn}
   alias Commanded.ExampleDomain.MoneyTransfer.Commands.TransferMoney
+  alias Commanded.ExampleDomain.BankAccount.Commands.WithdrawMoney
   alias Commanded.ExampleDomain.MoneyTransfer.Events.MoneyTransferRequested
   alias Commanded.Helpers.CommandAuditMiddleware
   alias Commanded.ProcessManagers.ProcessRouter
@@ -60,4 +61,26 @@ defmodule Commanded.ProcessManagers.ProcessManagerRoutingTest do
 
     assert [{^transfer_uuid, _}] = ProcessRouter.process_instances(process_router)
   end
+
+  test "should not create entirely new instance when process manager expected to continue" do
+    account_number1 = UUID.uuid4
+    transfer_uuid = UUID.uuid4
+
+    {:ok, process_router} = TransferMoneyProcessManager.start_link()
+
+    assert ProcessRouter.process_instances(process_router) == []
+
+    :timer.sleep 500
+
+    :ok = BankRouter.dispatch(%OpenAccount{account_number: account_number1, initial_balance: 1_000})
+    :ok = BankRouter.dispatch(%WithdrawMoney{
+      transfer_uuid: transfer_uuid,
+      account_number: account_number1,
+      amount: 100,
+    })
+
+    :timer.sleep 300
+
+    assert [] = ProcessRouter.process_instances(process_router)
+  end
 end