fix: make results nullable again if root level errors are enabled

lib/resource/resource.ex

@@ -610,9 +610,7 @@ defmodule AshGraphql.Resource do
             module: schema,
             name: to_string(mutation.name),
             description: Ash.Resource.Info.action(resource, mutation.action).description,
-            type: %Absinthe.Blueprint.TypeReference.NonNull{
-              of_type: String.to_atom("#{mutation.name}_result")
-            },
+            type: mutation_result_type(mutation.name, api),
             __reference__: ref(__ENV__)
           }
         end
@@ -656,9 +654,7 @@ defmodule AshGraphql.Resource do
           module: schema,
           name: to_string(mutation.name),
           description: Ash.Resource.Info.action(resource, mutation.action).description,
-          type: %Absinthe.Blueprint.TypeReference.NonNull{
-            of_type: String.to_atom("#{mutation.name}_result")
-          },
+          type: mutation_result_type(mutation.name, api),
           __reference__: ref(__ENV__)
         }
 
@@ -710,13 +706,18 @@ defmodule AshGraphql.Resource do
       module: schema,
       name: to_string(mutation.name),
       description: Ash.Resource.Info.action(resource, mutation.action).description,
-      type: %Absinthe.Blueprint.TypeReference.NonNull{
-        of_type: String.to_atom("#{mutation.name}_result")
-      },
+      type: mutation_result_type(mutation.name, api),
       __reference__: ref(__ENV__)
     }
   end
 
+  defp mutation_result_type(mutation_name, api) do
+    type = String.to_atom("#{mutation_name}_result")
+    root_level_errors? = AshGraphql.Api.Info.root_level_errors?(api)
+
+    maybe_wrap_non_null(type, not root_level_errors?)
+  end
+
   defp mutation_args(%{identity: false} = mutation, resource, schema) do
     mutation_read_args(mutation, resource, schema)
   end

test/errors_test.exs

@@ -12,8 +12,6 @@ defmodule AshGraphql.ErrorsTest do
   end
 
   test "errors can be configured to be shown in the root" do
-    Application.put_env(:ash_graphql, AshGraphql.Test.Api, graphql: [root_level_errors?: true])
-
     resp =
       """
       mutation CreatePost($input: CreatePostInput) {
@@ -27,7 +25,7 @@ defmodule AshGraphql.ErrorsTest do
         }
       }
       """
-      |> Absinthe.run(AshGraphql.Test.Schema,
+      |> Absinthe.run(AshGraphql.Test.RootLevelErrorsSchema,
         variables: %{
           "input" => %{
             "text" => "foobar",
@@ -38,7 +36,7 @@ defmodule AshGraphql.ErrorsTest do
 
     assert {:ok, result} = resp
 
-    assert %{data: nil, errors: [%{message: message}]} = result
+    assert %{data: %{"createPost" => nil}, errors: [%{message: message}]} = result
 
     assert message =~ "confirmation did not match value"
   end
@@ -111,8 +109,8 @@ defmodule AshGraphql.ErrorsTest do
   end
 
   test "showing raised errors alongside root errors shows raised errors in the root" do
-    Application.put_env(:ash_graphql, AshGraphql.Test.Api,
-      graphql: [show_raised_errors?: true, root_level_errors?: true]
+    Application.put_env(:ash_graphql, AshGraphql.Test.RootLevelErrorsApi,
+      graphql: [show_raised_errors?: true]
     )
 
     resp =
@@ -128,7 +126,7 @@ defmodule AshGraphql.ErrorsTest do
         }
       }
       """
-      |> Absinthe.run(AshGraphql.Test.Schema,
+      |> Absinthe.run(AshGraphql.Test.RootLevelErrorsSchema,
         variables: %{
           "input" => %{
             "text" => "foobar"
@@ -139,7 +137,7 @@ defmodule AshGraphql.ErrorsTest do
     assert {:ok, result} = resp
 
     assert %{
-             data: nil,
+             data: %{"createPostWithError" => nil},
              errors: [
                %{message: message}
              ]
@@ -415,4 +413,60 @@ defmodule AshGraphql.ErrorsTest do
     assert fields["type"]["ofType"]["kind"] == "NON_NULL"
     assert fields["type"]["ofType"]["ofType"]["name"] == "String"
   end
+
+  test "mutation result is non nullable without root level errors" do
+    {:ok, %{data: data}} =
+      """
+      query {
+        __schema {
+          mutationType {
+            name
+            fields {
+              name
+              type {
+                kind
+                ofType {
+                  name
+                }
+              }
+            }
+          }
+        }
+      }
+      """
+      |> Absinthe.run(AshGraphql.Test.Schema)
+
+    create_post_mutation =
+      data["__schema"]["mutationType"]["fields"]
+      |> Enum.find(fn field -> field["name"] == "createPost" end)
+
+    assert create_post_mutation["type"]["kind"] == "NON_NULL"
+    assert create_post_mutation["type"]["ofType"]["name"] == "CreatePostResult"
+  end
+
+  test "mutation result is nullable with root level errors" do
+    {:ok, %{data: data}} =
+      """
+      query {
+        __schema {
+          mutationType {
+            name
+            fields {
+              name
+              type {
+                name
+              }
+            }
+          }
+        }
+      }
+      """
+      |> Absinthe.run(AshGraphql.Test.RootLevelErrorsSchema)
+
+    create_post_mutation =
+      data["__schema"]["mutationType"]["fields"]
+      |> Enum.find(fn field -> field["name"] == "createPost" end)
+
+    assert create_post_mutation["type"]["name"] == "CreatePostResult"
+  end
 end

test/support/root_level_errors_api.ex

@@ -0,0 +1,17 @@
+defmodule AshGraphql.Test.RootLevelErrorsApi do
+  @moduledoc false
+
+  use Ash.Api,
+    extensions: [
+      AshGraphql.Api
+    ],
+    otp_app: :ash_graphql
+
+  graphql do
+    root_level_errors? true
+  end
+
+  resources do
+    registry(AshGraphql.Test.Registry)
+  end
+end

test/support/root_level_errors_schema.ex

@@ -0,0 +1,30 @@
+defmodule AshGraphql.Test.RootLevelErrorsSchema do
+  @moduledoc false
+
+  use Absinthe.Schema
+
+  @apis [AshGraphql.Test.RootLevelErrorsApi]
+
+  use AshGraphql, apis: @apis
+
+  query do
+  end
+
+  mutation do
+  end
+
+  object :foo do
+    field(:foo, :string)
+    field(:bar, :string)
+  end
+
+  input_object :foo_input do
+    field(:foo, non_null(:string))
+    field(:bar, non_null(:string))
+  end
+
+  enum :status do
+    value(:open, description: "The post is open")
+    value(:closed, description: "The post is closed")
+  end
+end