Handle disconnect when channel is not initialized (#23)

fixes #22

Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>

Author: yordis

lib/conn_grpc/channel.ex

@@ -253,14 +253,17 @@ defmodule ConnGRPC.Channel do
   defp handle_disconnect(state) do
     now = System.monotonic_time()
     debug(state, "Connection down")
-    state.on_disconnect.()
-    state.channel.adapter.disconnect(state.channel)
 
-    :telemetry.execute(
-      [:conn_grpc, :channel, :disconnected],
-      %{duration: now - state.connection_start},
-      telemetry_metadata(state)
-    )
+    if state.channel do
+      state.on_disconnect.()
+      state.channel.adapter.disconnect(state.channel)
+
+      :telemetry.execute(
+        [:conn_grpc, :channel, :disconnected],
+        %{duration: now - state.connection_start},
+        telemetry_metadata(state)
+      )
+    end
 
     state = %{state | channel: nil}
     schedule_retry(state)

test/conn_grpc/channel_test.exs

@@ -176,6 +176,24 @@ defmodule ConnGRPC.ChannelTest do
         _metadata = %{channel_name: :test_channel}
       }
     end
+
+    test "handles disconnect when channel is not yet connected" do
+      {:ok, channel_pid} =
+        Channel.start_link(
+          address: "address",
+          opts: [adapter: GRPC.Client.TestAdapters.Error],
+          on_disconnect: fn -> send(:channel_test, :disconnect_called) end,
+          backoff_module: ConnGRPC.Backoff.NoRetry
+        )
+
+      # Verify channel is not connected before sending disconnect
+      assert {:error, :not_connected} = Channel.get(channel_pid)
+
+      send(channel_pid, {:gun_down, fake_pid(), :http2, :normal, []})
+
+      refute_receive :disconnect_called
+      assert Process.alive?(channel_pid)
+    end
   end
 
   describe "Mint disconnect handling" do
@@ -223,6 +241,24 @@ defmodule ConnGRPC.ChannelTest do
         _metadata = %{channel_name: :test_channel}
       }
     end
+
+    test "handles disconnect when channel is not yet connected" do
+      {:ok, channel_pid} =
+        Channel.start_link(
+          address: "address",
+          opts: [adapter: GRPC.Client.TestAdapters.Error],
+          on_disconnect: fn -> send(:channel_test, :disconnect_called) end,
+          backoff_module: ConnGRPC.Backoff.NoRetry
+        )
+
+      # Verify channel is not connected before sending disconnect
+      assert {:error, :not_connected} = Channel.get(channel_pid)
+
+      send(channel_pid, {:elixir_grpc, :connection_down, fake_pid()})
+
+      refute_receive :disconnect_called
+      assert Process.alive?(channel_pid)
+    end
   end
 
   describe "Retry and backoff" do