return pm.patchMergeKey
}

func (pm *PatchMeta) SetPatchMergeKey(pmk string) {
	pm.patchMergeKey = pmk
}

type LookupPatchMeta interface {
	// LookupPatchMetadataForStruct gets subschema and the patch metadata (e.g. patch strategy and merge key) for map.
	LookupPatchMetadataForStruct(key string) (LookupPatchMeta, PatchMeta, error)
	// LookupPatchMetadataForSlice get subschema and the patch metadata for slice.

		Key   string
		Value string
	}
	type Outer struct {
		Inner []Elem `json:"inner" patchStrategy:"merge" patchMergeKey:"key"`
	}
	outer := &Outer{}
	elemType, patchStrategies, patchMergeKey, err := LookupPatchMetadataForStruct(reflect.TypeOf(outer), "inner")
	if err != nil {
		t.Fatal(err)
	}
	if elemType != reflect.TypeOf([]Elem{}) {
		t.Errorf("elemType = %v, want: %v", elemType, reflect.TypeOf([]Elem{}))
	}

// struct field given the struct type and the JSON name of the field.
// It returns field type, a slice of patch strategies, merge key and error.
// TODO: fix the returned errors to be introspectable.
func LookupPatchMetadataForStruct(t reflect.Type, jsonField string) (
	elemType reflect.Type, patchStrategies []string, patchMergeKey string, e error) {
	if t.Kind() == reflect.Pointer {
		t = t.Elem()
	}

	if t.Kind() != reflect.Struct {

func handleMapDiff(key string, originalValue, modifiedValue, patch map[string]interface{},
	schema LookupPatchMeta, diffOptions DiffOptions) error {
	subschema, patchMeta, err := schema.LookupPatchMetadataForStruct(key)

	if err != nil {
		// We couldn't look up metadata for the field
		// If the values are identical, this doesn't matter, no patch is needed
		if reflect.DeepEqual(originalValue, modifiedValue) {