Handle index out of range when reading arrays

Author: mikefarah

data_navigator.go

@@ -36,6 +36,10 @@ func recurse(value interface{}, head string, tail []string) interface{} {
 }
 
 func readArray(array []interface{}, head int64, tail []string) interface{} {
+	if head > int64(len(array)) {
+		return nil
+	}
+
 	value := array[head]
 	if len(tail) > 0 {
 		return recurse(value, tail[0], tail[1:len(tail)])

data_navigator_test.go

@@ -35,6 +35,10 @@ func TestReadMap_array(t *testing.T) {
 	assertResult(t, 4, readMap(parsedData, "b", []string{"d", "1"}))
 }
 
+func TestReadMap_array_out_of_bounds(t *testing.T) {
+	assertResult(t, nil, readMap(parsedData, "b", []string{"d", "3"}))
+}
+
 func TestWrite_simple(t *testing.T) {
 
 	write(parsedData, "b", []string{"c"}, "4")