Adjust stop reasons for server processes (#958)

* Adjust stop reasons for server processes

* Update lib/livebook/unique_task.ex

Co-authored-by: José Valim <jose.valim@dashbit.co>

Co-authored-by: José Valim <jose.valim@dashbit.co>

app_builder/examples/wx_demo/lib/wx_demo.ex

@@ -57,13 +57,13 @@ defmodule WxDemo.Window do
   @impl true
   def handle_event({:wx, @wx_id_exit, _, _, _}, state) do
     :init.stop()
-    {:stop, :normal, state}
+    {:stop, :shutdown, state}
   end
 
   @impl true
   def handle_event({:wx, _, _, _, {:wxClose, :close_window}}, state) do
     :init.stop()
-    {:stop, :normal, state}
+    {:stop, :shutdown, state}
   end
 
   @impl true

lib/livebook/runtime/erl_dist/node_manager.ex

@@ -38,9 +38,9 @@ defmodule Livebook.Runtime.ErlDist.NodeManager do
     * `:auto_termination` - whether to terminate the manager
       when the last runtime server terminates. Defaults to `true`.
 
-    * `:parent_node` - indicates which node spawned the node manager.  
-       It is used to disconnect the node when the server terminates, 
-       which happens when the last session using the node disconnects.  
+    * `:parent_node` - indicates which node spawned the node manager.
+       It is used to disconnect the node when the server terminates,
+       which happens when the last session using the node disconnects.
        Defaults to `nil`
   """
   def start(opts \\ []) do
@@ -140,8 +140,11 @@ defmodule Livebook.Runtime.ErlDist.NodeManager do
   def handle_info({:DOWN, _, :process, pid, _}, state) do
     if pid in state.runtime_servers do
       case update_in(state.runtime_servers, &List.delete(&1, pid)) do
-        %{runtime_servers: [], auto_termination: true} = state -> {:stop, :normal, state}
-        state -> {:noreply, state}
+        %{runtime_servers: [], auto_termination: true} = state ->
+          {:stop, :shutdown, state}
+
+        state ->
+          {:noreply, state}
       end
     else
       {:noreply, state}

lib/livebook/runtime/erl_dist/runtime_server.ex

@@ -161,7 +161,7 @@ defmodule Livebook.Runtime.ErlDist.RuntimeServer do
   end
 
   def handle_info({:DOWN, _, :process, owner, _}, %{owner: owner} = state) do
-    {:stop, :normal, state}
+    {:stop, :shutdown, state}
   end
 
   def handle_info({:DOWN, _, :process, pid, reason}, state) do

lib/livebook/unique_task.ex

@@ -17,7 +17,7 @@ defmodule Livebook.UniqueTask.Task do
   @impl true
   def handle_continue(fun, state) do
     fun.()
-    {:stop, :normal, state}
+    {:stop, :shutdown, state}
   end
 end
 
@@ -75,6 +75,8 @@ defmodule Livebook.UniqueTask do
       {:DOWN, ^ref, :process, ^pid, reason} ->
         case reason do
           :normal -> :ok
+          :shutdown -> :ok
+          {:shutdown, _} -> :ok
           :noproc -> :ok
           _ -> :error
         end

lib/livebook_app.ex

@@ -45,13 +45,13 @@ if Mix.target() == :app do
     @impl true
     def handle_event({:wx, @wx_id_exit, _, _, _}, state) do
       :init.stop()
-      {:stop, :normal, state}
+      {:stop, :shutdown, state}
     end
 
     @impl true
     def handle_event({:wx, _, _, _, {:wxClose, :close_window}}, state) do
       :init.stop()
-      {:stop, :normal, state}
+      {:stop, :shutdown, state}
     end
 
     # TODO: investigate "Universal Links" [1], that is, instead of livebook://foo, we have