FunctionClauseError for Socket.handle_info(:ssl_error)

[Sinc63]

Environment

Using version 0.4.4

• Elixir & Erlang/OTP versions (elixir --version):
  Erlang/OTP 23 [erts-11.0.2] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [hipe]

Elixir 1.10.3 (compiled with Erlang/OTP 23)

• Operating system:

Current behavior

Include code samples, errors and stacktraces if appropriate.
[error] function=error_info/7 line=934 module=gen_server GenServer #PID<0.931.0> terminating
** (FunctionClauseError) no function clause matching in Kadabra.Socket.handle_info/2
(kadabra 0.4.4) lib/socket.ex:170: Kadabra.Socket.handle_info({:ssl_error, {:sslsocket, {:gen_tcp, #Port<0.57>, :tls_connection, :undefined}, [#PID<0.933.0>, #PID<0.932.0>]}, {:tls_alert, {:certificate_expired, 'TLS client: In state connection received SERVER ALERT: Fatal - Certificate Expired\n '}}}, %Kadabra.Socket{active_user: #PID<0.928.0>, buffer: "", socket: {:sslsocket, {:gen_tcp, #Port<0.57>, :tls_connection, :undefined}, [#PID<0.933.0>, #PID<0.932.0>]}})
(stdlib 3.13) gen_server.erl:680: :gen_server.try_dispatch/4
(stdlib 3.13) gen_server.erl:756: :gen_server.handle_msg/6
(stdlib 3.13) proc_lib.erl:226: :proc_lib.init_p_do_apply/3
Last message: {:ssl_error, {:sslsocket, {:gen_tcp, #Port<0.57>, :tls_connection, :undefined}, [#PID<0.933.0>, #PID<0.932.0>]}, {:tls_alert, {:certificate_expired, 'TLS client: In state connection received SERVER ALERT: Fatal - Certificate Expired\n '}}}#012State: %Kadabra.Socket{active_user: #PID<0.928.0>, buffer: "", socket: {:sslsocket, {:gen_tcp, #Port<0.57>, :tls_connection, :undefined}, [#PID<0.933.0>, #PID<0.932.0>]}}

Expected behavior

A result as expected as :ssl_error should be explicitly handled.

[Sinc63]

A possible solution would be to add a function clause along the lines of:

  def handle_info({:ssl_error, _, reason}, state) do
    Kernel.send(state.active_user, {:closed, self()})
    {:noreply, %{state | socket: nil}}
  end

I initially found a warning quite helpful in my system because it gave the only explicit indication that my Apple Push Notification Service certificate was expired. The only other symptom was intermittent timeout failures. Now however with this function in place I seem to consistently get the log from tls decode with the error content, so I removed the warning from the suggested code.

I'm not sure if sending :closed is the right result, but it seems to be working for me.