Ensure socket owner always exits (#266)

lib/redix/connection.ex

@@ -271,9 +271,13 @@ defmodule Redix.Connection do
  {:keep_state, data, actions}
 
  {:error, _reason} ->
- # The socket owner will get a closed message at some point, so we just move to the
- # disconnected state.
+ # The socket owner is not guaranteed to get a "closed" message, even if we close the
+ # socket here. So, we move to the disconnected state but also notify the owner that
+ # sending failed. If the owner already got the "closed" message, it exited so this
+ # message goes nowere, otherwise the socket owner will exit and notify the connection.
+ # See https://github.com/whatyouhide/redix/issues/265.
  :ok = data.transport.close(data.socket)
+ send(data.socket_owner, {:send_errored, self()})
  {:next_state, :disconnected, data}
  end
  else

lib/redix/socket_owner.ex

@@ -50,6 +50,19 @@ defmodule Redix.SocketOwner do
  end
  end
 
+ # The connection is notifying the socket owner that sending failed. If the socket owner
+ # gets this, it can stop normally without waiting for the "closed"/"error" network
+ # message from the socket.
+ def handle_info({:send_errored, conn}, %__MODULE__{conn: conn} = state) do
+ error =
+ case state.transport do
+ :ssl -> {:ssl_error, :closed}
+ :gen_tcp -> {:tcp_error, :closed}
+ end
+
+ stop(error, state)
+ end
+
  def handle_info({transport, socket, data}, %__MODULE__{socket: socket} = state)
  when transport in [:tcp, :ssl] do
  :ok = setopts(state, socket, active: :once)