Merge pull request #838 from 99designs/fix-directive-nil

fix directives return nil handling

codegen/field.gotpl

@@ -104,14 +104,12 @@
 		if err != nil {
 			return nil, err
 		}
+		if tmp == nil {
+		    return nil, nil
+		}
 		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/testserver/directive.graphql

@@ -14,6 +14,7 @@ extend type Query {
     directiveInput(arg: InputDirectives!): String
     directiveInputType(arg: InnerInput! @custom): String
     directiveObject: ObjectDirectives
+    directiveObjectWithCustomGoModel: ObjectDirectivesWithCustomGoModel
     directiveFieldDef(ret: String!): String! @length(min: 1, message: "not valid")
     directiveField: String
     directiveDouble: String @directive1 @directive2
@@ -36,3 +37,7 @@ type ObjectDirectives {
     text: String! @length(min: 0, max: 7, message: "not valid")
     nullableText: String @toNull
 }
+
+type ObjectDirectivesWithCustomGoModel {
+    nullableText: String @toNull
+}

codegen/testserver/directive_test.go

@@ -47,6 +47,13 @@ func TestDirectives(t *testing.T) {
 		}, nil
 	}
 
+	resolvers.QueryResolver.DirectiveObjectWithCustomGoModel = func(ctx context.Context) (*ObjectDirectivesWithCustomGoModel, error) {
+		s := "Ok"
+		return &ObjectDirectivesWithCustomGoModel{
+			NullableText: s,
+		}, nil
+	}
+
 	resolvers.QueryResolver.DirectiveField = func(ctx context.Context) (*string, error) {
 		if s, ok := ctx.Value("request_id").(*string); ok {
 			return s, nil
@@ -350,5 +357,17 @@ func TestDirectives(t *testing.T) {
 			require.Equal(t, "Ok", resp.DirectiveObject.Text)
 			require.True(t, resp.DirectiveObject.NullableText == nil)
 		})
+		t.Run("when directive returns nil & custom go field is not nilable", func(t *testing.T) {
+			var resp struct {
+				DirectiveObjectWithCustomGoModel *struct {
+					NullableText *string
+				}
+			}
+
+			err := c.Post(`query { directiveObjectWithCustomGoModel{ nullableText } }`, &resp)
+
+			require.Nil(t, err)
+			require.True(t, resp.DirectiveObjectWithCustomGoModel.NullableText == nil)
+		})
 	})
 }