[GRAPH-1099] Allows a 3-tuple to be return for config errors

lib/absinthe/phase/subscription/subscribe_self.ex

@@ -75,25 +75,31 @@ defmodule Absinthe.Phase.Subscription.SubscribeSelf do
         {:ok, config}
 
       {:error, msg} ->
-        error = %Phase.Error{
-          phase: __MODULE__,
-          message: msg,
-          locations: [field.source_location]
-        }
+        {:error, create_config_error(field, msg)}
 
-        {:error, error}
+      {:error, msg, extra} ->
+        {:error, create_config_error(field, msg, extra)}
 
       val ->
         raise """
         Invalid return from config function!
 
-        A config function must return `{:ok, config}` or `{:error, msg}`. You returned:
+        A config function must return `{:ok, config}`, `{:error, msg}` or `{:error, msg, extra}`. You returned:
 
         #{inspect(val)}
         """
     end
   end
 
+  defp create_config_error(field, msg, extra \\ %{}) do
+    %Phase.Error{
+      phase: __MODULE__,
+      message: msg,
+      locations: [field.source_location],
+      extra: extra
+    }
+  end
+
   defp get_field_keys(%{schema_node: schema_node} = _field, config) do
     name = schema_node.identifier
 

test/absinthe/execution/subscription_test.exs

@@ -214,6 +214,18 @@ defmodule Absinthe.Execution.SubscriptionTest do
           {:ok, topic: "*", context_id: "*", document_id: op_name}
         end
       end
+
+      field :config_error, :string do
+        config fn _, _ ->
+          {:error, "failed"}
+        end
+      end
+
+      field :config_error_with_extra, :string do
+        config fn _, _ ->
+          {:error, "failed", %{code: "FAILED"}}
+        end
+      end
     end
 
     mutation do
@@ -584,6 +596,47 @@ defmodule Absinthe.Execution.SubscriptionTest do
     assert_receive(:batch_get_group)
   end
 
+  @query """
+  subscription Example {
+    configError
+  }
+  """
+  test "config errors" do
+    assert {:ok, %{errors: [%{message: "failed"}]}} =
+             run_subscription(
+               @query,
+               Schema,
+               variables: %{},
+               context: %{pubsub: PubSub}
+             )
+  end
+
+  @query """
+  subscription Example {
+    configErrorWithExtra
+  }
+  """
+  test "config errors with extra" do
+    assert {:ok, %{errors: [%{message: "failed", code: "FAILED"}]}} =
+             run_subscription(
+               @query,
+               Schema,
+               variables: %{},
+               context: %{pubsub: PubSub}
+             )
+  end
+
+  test "config errors with extra and spec_compliant_errors turned on" do
+    assert {:ok, %{errors: [%{message: "failed", extensions: %{code: "FAILED"}}]}} =
+             run_subscription(
+               @query,
+               Schema,
+               variables: %{},
+               context: %{pubsub: PubSub},
+               spec_compliant_errors: true
+             )
+  end
+
   describe "subscription_ids" do
     @query """
     subscription {