ensure default resolver can traverse embedded structs (#2341)

Signed-off-by: James Phillips <jamesdphillips@gmail.com>

backend/apid/graphql/globalid/entity.go

@@ -13,7 +13,7 @@ var entityName = "entities"
 // EntityTranslator global ID resource
 var EntityTranslator = commonTranslator{
 	name:       entityName,
-	encodeFunc: standardEncoder(entityName, "ID"),
+	encodeFunc: standardEncoder(entityName, "Name"),
 	decodeFunc: standardDecoder,
 	isResponsibleFunc: func(record interface{}) bool {
 		_, ok := record.(*types.Entity)

backend/apid/graphql/globalid/handlers.go

@@ -11,7 +11,7 @@ var handlerName = "handlers"
 // HandlerTranslator global ID resource
 var HandlerTranslator = commonTranslator{
 	name:       handlerName,
-	encodeFunc: standardEncoder(handlerName, "ID"),
+	encodeFunc: standardEncoder(handlerName, "Name"),
 	decodeFunc: standardDecoder,
 	isResponsibleFunc: func(record interface{}) bool {
 		_, ok := record.(*types.Handler)

backend/apid/graphql/globalid/silences.go

@@ -11,7 +11,7 @@ var silenceName = "silences"
 // SilenceTranslator global ID resource
 var SilenceTranslator = commonTranslator{
 	name:       silenceName,
-	encodeFunc: standardEncoder(silenceName, "ID"),
+	encodeFunc: standardEncoder(silenceName, "Name"),
 	decodeFunc: standardDecoder,
 	isResponsibleFunc: func(record interface{}) bool {
 		_, ok := record.(*types.Silenced)

graphql/resolvers.go

@@ -146,38 +146,8 @@ func DefaultResolver(source interface{}, fieldName string) (interface{}, error)
 
 	// Struct
 	if sourceVal.Type().Kind() == reflect.Struct {
-		fieldName = strings.Title(fieldName)
-		for i := 0; i < sourceVal.NumField(); i++ {
-			valueField := sourceVal.Field(i)
-			typeField := sourceVal.Type().Field(i)
-			if typeField.Name == fieldName {
-				// If ptr and value is nil return nil
-				if valueField.Type().Kind() == reflect.Ptr && valueField.IsNil() {
-					return nil, nil
-				}
-				return valueField.Interface(), nil
-			}
-			tag := typeField.Tag
-			checkTag := func(tagName string) bool {
-				t := tag.Get(tagName)
-				tOptions := strings.Split(t, ",")
-				if len(tOptions) == 0 {
-					return false
-				}
-				if tOptions[0] != fieldName {
-					return false
-				}
-				return true
-			}
-			if checkTag("json") || checkTag("graphql") {
-				return valueField.Interface(), nil
-			}
-			if valueField.Kind() == reflect.Struct && typeField.Anonymous {
-				return DefaultResolver(valueField.Interface(), fieldName)
-			}
-			continue
-		}
-		return nil, nil
+		_, val, err := findFieldInStruct(sourceVal, fieldName)
+		return val, err
 	}
 
 	// map[string]interface
@@ -198,6 +168,46 @@ func DefaultResolver(source interface{}, fieldName string) (interface{}, error)
 	return nil, nil
 }
 
+func findFieldInStruct(source reflect.Value, fieldName string) (bool, interface{}, error) {
+	for i := 0; i < source.NumField(); i++ {
+		fieldValue := source.Field(i)
+		fieldType := source.Type().Field(i)
+
+		if fieldType.Name == strings.Title(fieldName) {
+			// If ptr and value is nil return nil
+			if fieldValue.Type().Kind() == reflect.Ptr && fieldValue.IsNil() {
+				return true, nil, nil
+			}
+			return true, fieldValue.Interface(), nil
+		}
+
+		tag := fieldType.Tag
+		checkTag := func(tagName string) bool {
+			t := tag.Get(tagName)
+			tOptions := strings.Split(t, ",")
+			if len(tOptions) == 0 {
+				return false
+			}
+			if tOptions[0] != fieldName {
+				return false
+			}
+			return true
+		}
+		if checkTag("json") || checkTag("graphql") {
+			return true, fieldValue.Interface(), nil
+		}
+
+		if fieldValue.Kind() == reflect.Struct && fieldType.Anonymous {
+			if ok, val, err := findFieldInStruct(fieldValue, fieldName); ok {
+				return ok, val, err
+			}
+		}
+		continue
+	}
+
+	return false, nil, nil
+}
+
 type typeResolver interface {
 	ResolveType(interface{}, ResolveTypeParams) *Type
 }

graphql/resolvers_test.go

@@ -0,0 +1,73 @@
+package graphql
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDefaultResolver(t *testing.T) {
+	type meta struct {
+		Name string `json:"firstname"`
+	}
+
+	type animal struct {
+		meta
+		Age int
+	}
+
+	fren := animal{meta: meta{Name: "bob"}, Age: 10}
+
+	testCases := []struct {
+		desc   string
+		source interface{}
+		field  string
+		out    interface{}
+	}{
+		{
+			desc:   "field on struct",
+			source: fren,
+			field:  "name",
+			out:    "bob",
+		},
+		{
+			desc:   "second field on struct",
+			source: fren,
+			field:  "age",
+			out:    10,
+		},
+		{
+			desc:   "field on struct w/ tag",
+			source: fren,
+			field:  "firstname",
+			out:    "bob",
+		},
+		{
+			desc:   "missing field on struct",
+			source: fren,
+			field:  "surname",
+			out:    nil,
+		},
+		{
+			desc:   "field on map",
+			source: map[string]interface{}{"name": "bob"},
+			field:  "name",
+			out:    "bob",
+		},
+		{
+			desc:   "missing field on map",
+			source: map[string]interface{}{"name": "bob"},
+			field:  "firstname",
+			out:    nil,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.desc, func(t *testing.T) {
+			result, err := DefaultResolver(tc.source, tc.field)
+			require.NoError(t, err)
+			assert.EqualValues(t, result, tc.out)
+		})
+	}
+}