amend ret nil on err

Author: elianddb

sql/types/json.go

@@ -62,17 +62,17 @@ func convertJSONValue(v interface{}) (interface{}, sql.ConvertInRange, error) {
 		if b, berr := json.Marshal(v); berr == nil {
 			data = b
 		} else {
-			return JSONDocument{Val: nil}, sql.InRange, nil
+			return nil, sql.InRange, nil
 		}
 	}
 
 	if int64(len(data))*charsetMaxLength > MaxJsonFieldByteLength {
-		return JSONDocument{Val: nil}, sql.InRange, ErrLengthTooLarge.New(len(data), MaxJsonFieldByteLength)
+		return nil, sql.InRange, ErrLengthTooLarge.New(len(data), MaxJsonFieldByteLength)
 	}
 
 	var val interface{}
 	if err := json.Unmarshal(data, &val); err != nil {
-		return JSONDocument{Val: nil}, sql.OutOfRange, sql.ErrInvalidJson.New(err.Error())
+		return nil, sql.OutOfRange, sql.ErrInvalidJson.New(err.Error())
 	}
 
 	return JSONDocument{Val: val}, sql.InRange, nil