Fix pointer returns from directive

codegen/args.gotpl

@@ -14,6 +14,10 @@ func (ec *executionContext) {{ $name }}(ctx context.Context, rawArgs map[string]
 				}
 				if data, ok := tmp.({{ $arg.TypeReference.GO | ref }}) ; ok {
 					arg{{$i}} = data
+				{{- if $arg.TypeReference.IsNilable }}
+					} else if tmp == nil {
+						arg{{$i}} = nil
+				{{- end }}
 				} else {
 					return nil, fmt.Errorf(`unexpected type %T from directive, should be {{ $arg.TypeReference.GO }}`, tmp)
 				}

codegen/field.gotpl

@@ -107,6 +107,11 @@
 		if data, ok := tmp.({{ .TypeReference.GO | ref }}) ; ok {
 			return data, nil
 		}
+		{{- if .TypeReference.IsNilable -}}
+			else if tmp == nil {
+				return nil, nil
+			}
+		{{- end }}
 		return nil, fmt.Errorf(`unexpected type %T from directive, should be {{ .TypeReference.GO }}`, tmp)
 	{{- else -}}
 		ctx = rctx  // use context from middleware stack in children

codegen/input.gotpl

@@ -25,6 +25,10 @@
 					}
 					if data, ok := tmp.({{ $field.TypeReference.GO | ref }}) ; ok {
 						it.{{$field.GoFieldName}} = data
+					{{- if $field.TypeReference.IsNilable }}
+						} else if tmp == nil {
+							it.{{$field.GoFieldName}} = nil
+					{{- end }}
 					} else {
 						return it, fmt.Errorf(`unexpected type %T from directive, should be {{ $field.TypeReference.GO }}`, tmp)
 					}

codegen/testserver/directive.graphql

@@ -2,19 +2,22 @@ directive @length(min: Int!, max: Int, message: String) on ARGUMENT_DEFINITION |
 directive @range(min: Int = 0, max: Int) on ARGUMENT_DEFINITION
 directive @custom on ARGUMENT_DEFINITION
 directive @logged(id: UUID!) on FIELD
+directive @toNull on ARGUMENT_DEFINITION | INPUT_FIELD_DEFINITION | FIELD_DEFINITION
 
 extend type Query {
     directiveArg(arg: String! @length(min:1, max: 255, message: "invalid length")): String
-    directiveNullableArg(arg: Int @range(min:0), arg2: Int @range): String
+    directiveNullableArg(arg: Int @range(min:0), arg2: Int @range, arg3: String @toNull): String
     directiveInputNullable(arg: InputDirectives): String
     directiveInput(arg: InputDirectives!): String
     directiveInputType(arg: InnerInput! @custom): String
+    directiveObject: ObjectDirectives
     directiveFieldDef(ret: String!): String! @length(min: 1, message: "not valid")
     directiveField: String
 }
 
 input InputDirectives {
     text: String! @length(min: 0, max: 7, message: "not valid")
+    nullableText: String @toNull
     inner: InnerDirectives!
     innerNullable: InnerDirectives
     thirdParty: ThirdParty @length(min: 0, max: 7)
@@ -23,3 +26,8 @@ input InputDirectives {
 input InnerDirectives {
     message: String! @length(min: 1, message: "not valid")
 }
+
+type ObjectDirectives {
+    text: String! @length(min: 0, max: 7, message: "not valid")
+    nullableText: String @toNull
+}

codegen/testserver/directive_test.go

@@ -29,7 +29,7 @@ func TestDirectives(t *testing.T) {
 		return &s, nil
 	}
 
-	resolvers.QueryResolver.DirectiveNullableArg = func(ctx context.Context, arg *int, arg2 *int) (i *string, e error) {
+	resolvers.QueryResolver.DirectiveNullableArg = func(ctx context.Context, arg *int, arg2 *int, arg3 *string) (*string, error) {
 		s := "Ok"
 		return &s, nil
 	}
@@ -39,6 +39,14 @@ func TestDirectives(t *testing.T) {
 		return &s, nil
 	}
 
+	resolvers.QueryResolver.DirectiveObject = func(ctx context.Context) (*ObjectDirectives, error) {
+		s := "Ok"
+		return &ObjectDirectives{
+			Text:         s,
+			NullableText: &s,
+		}, nil
+	}
+
 	resolvers.QueryResolver.DirectiveField = func(ctx context.Context) (*string, error) {
 		if s, ok := ctx.Value("request_id").(*string); ok {
 			return s, nil
@@ -115,6 +123,9 @@ func TestDirectives(t *testing.T) {
 					Logged: func(ctx context.Context, obj interface{}, next graphql.Resolver, id string) (interface{}, error) {
 						return next(context.WithValue(ctx, "request_id", &id))
 					},
+					ToNull: func(ctx context.Context, obj interface{}, next graphql.Resolver) (interface{}, error) {
+						return nil, nil
+					},
 				},
 			}),
 			handler.ResolverMiddleware(func(ctx context.Context, next graphql.Resolver) (res interface{}, err error) {
@@ -271,7 +282,7 @@ func TestDirectives(t *testing.T) {
 				DirectiveInputNullable *string
 			}
 
-			err := c.Post(`query { directiveInputNullable(arg: {text:"23",inner:{message:"1"},innerNullable:{message:"success"}}) }`, &resp)
+			err := c.Post(`query { directiveInputNullable(arg: {text:"23",nullableText:"23",inner:{message:"1"},innerNullable:{message:"success"}}) }`, &resp)
 
 			require.Nil(t, err)
 			require.Equal(t, "Ok", *resp.DirectiveInputNullable)
@@ -287,4 +298,20 @@ func TestDirectives(t *testing.T) {
 			require.Equal(t, "Ok", *resp.DirectiveInputType)
 		})
 	})
+	t.Run("object field directives", func(t *testing.T) {
+		t.Run("when function success", func(t *testing.T) {
+			var resp struct {
+				DirectiveObject *struct {
+					Text         string
+					NullableText *string
+				}
+			}
+
+			err := c.Post(`query { directiveObject{ text nullableText } }`, &resp)
+
+			require.Nil(t, err)
+			require.Equal(t, "Ok", resp.DirectiveObject.Text)
+			require.True(t, resp.DirectiveObject.NullableText == nil)
+		})
+	})
 }