Catch :noproc errors in Xandra.Connection

lib/xandra/cluster.ex

@@ -434,12 +434,7 @@ defmodule Xandra.Cluster do
       cluster,
       options,
       fn conn ->
-        try do
-          Xandra.execute(conn, batch, options_without_retry_strategy)
-        catch
-          :exit, {:noproc, _} ->
-            {:error, ConnectionError.new("execute", {:cluster, :pool_closed})}
-        end
+        Xandra.execute(conn, batch, options_without_retry_strategy)
       end
     )
   end
@@ -463,12 +458,7 @@ defmodule Xandra.Cluster do
       cluster,
       options,
       fn conn ->
-        try do
-          Xandra.execute(conn, query, params, options_without_retry_strategy)
-        catch
-          :exit, {:noproc, _} ->
-            {:error, ConnectionError.new("execute", {:cluster, :pool_closed})}
-        end
+        Xandra.execute(conn, query, params, options_without_retry_strategy)
       end
     )
   end

lib/xandra/connection.ex

@@ -65,7 +65,7 @@ defmodule Xandra.Connection do
 
     telemetry_metadata = Keyword.fetch!(options, :telemetry_metadata)
 
-    case :gen_statem.call(conn_pid, {:checkout_state_for_next_request, req_alias}) do
+    case gen_statem_call_trapping_noproc(conn_pid, {:checkout_state_for_next_request, req_alias}) do
       {:ok, checked_out_state() = state} ->
         checked_out_state(
           protocol_module: protocol_module,
@@ -159,7 +159,7 @@ defmodule Xandra.Connection do
     conn_pid = GenServer.whereis(conn)
     req_alias = Process.monitor(conn_pid, alias: :reply_demonitor)
 
-    case :gen_statem.call(conn_pid, {:checkout_state_for_next_request, req_alias}) do
+    case gen_statem_call_trapping_noproc(conn_pid, {:checkout_state_for_next_request, req_alias}) do
       {:ok, checked_out_state() = checked_out_state} ->
         checked_out_state(
           transport: %Transport{} = transport,
@@ -226,6 +226,12 @@ defmodule Xandra.Connection do
     end
   end
 
+  defp gen_statem_call_trapping_noproc(pid, call) do
+    :gen_statem.call(pid, call)
+  catch
+    :exit, {:noproc, _} -> {:error, :no_connection_process}
+  end
+
   defp hydrate_query(%Simple{} = simple, checked_out_state() = response, options) do
     %Simple{
       simple

lib/xandra/connection_error.ex

@@ -67,6 +67,10 @@ defmodule Xandra.ConnectionError do
     "connection dropped in the middle of a request"
   end
 
+  defp format_reason(:no_connection_process) do
+    "the connection process doesn't exist"
+  end
+
   defp format_reason({:connection_process_crashed, reason}) do
     "connection process crashed before sending a response with reason: #{inspect(reason)}"
   end

test/integration/errors_test.exs

@@ -94,7 +94,8 @@ defmodule ErrorsTest do
     test "noproc errors are caught" do
       {:ok, cluster} = start_supervised(Xandra.Cluster.PoolMock)
 
-      assert {:error, %ConnectionError{action: "execute", reason: {:cluster, :pool_closed}}} =
+      assert {:error,
+              %ConnectionError{action: "check out connection", reason: :no_connection_process}} =
                Cluster.execute(cluster, "select * from system.peers")
     end
   end

test/xandra_test.exs

@@ -307,6 +307,22 @@ defmodule XandraTest do
       assert {:ok, prepared} = Xandra.prepare(conn, "SELECT * FROM system.local")
       assert {:ok, %Xandra.Page{}} = Xandra.execute(conn, prepared, [])
     end
+
+    test "returns an error when the Connection process doesn't exist" do
+      dead_pid = dead_pid()
+
+      assert {:error,
+              %ConnectionError{action: "check out connection", reason: :no_connection_process}} =
+               Xandra.prepare(dead_pid, "SELECT * FROM system.local")
+
+      refute_receive {:DOWN, _ref, :process, _pid, :noproc}, 5
+
+      assert {:error,
+              %ConnectionError{action: "check out connection", reason: :no_connection_process}} =
+               Xandra.execute(dead_pid, "SELECT * FROM system.local")
+
+      refute_receive {:DOWN, _ref, :process, _pid, :noproc}, 5
+    end
   end
 
   describe "failure handling" do
@@ -390,4 +406,12 @@ defmodule XandraTest do
     send(pid, {ref, options})
     Keyword.replace!(options, :nodes, original_start_options[:nodes])
   end
+
+  defp dead_pid do
+    {pid, ref} = spawn_monitor(fn -> :ok end)
+
+    receive do
+      {:DOWN, ^ref, _, _, _} -> pid
+    end
+  end
 end