Apply dummy last key to VarDB

* Add DUMMY to KeyType class

iconservice/iconscore/db.py

@@ -46,6 +46,7 @@ class KeyType(Enum):
  SUB = auto()
 
  ARRAY_SIZE = auto()
+ DUMMY = auto()
  LAST = auto()
 
 
@@ -170,7 +171,8 @@ def _get_container_final_key_with_pipe(self, last_key: Key) -> List[bytes]:
  keys.append(self._tag.value)
  keys.append(key.value)
 
- keys.append(last_key.value)
+ if last_key.type != KeyType.DUMMY:
+ keys.append(last_key.value)
 
  return keys
 

iconservice/iconscore/icon_container_db.py

@@ -284,6 +284,7 @@ class VarDB(object):
  :K: [int, str, Address, bytes]
  :V: [int, str, Address, bytes, bool]
  """
+ _DUMMY_LAST_KEY = Key(b"", KeyType.DUMMY)
 
  def __init__(self, var_key: K, db: 'IconScoreDatabase', value_type: type) -> None:
  # Use var_key as a db prefix in the case of VarDB
@@ -297,21 +298,24 @@ def set(self, value: V) -> None:
  :param value: a value to be set
  """
  byte_value = ContainerUtil.encode_value(value)
- self._db.put(b"", byte_value)
+ self._db.put(self._DUMMY_LAST_KEY, byte_value)
 
  def get(self) -> Optional[V]:
  """
  Gets the value
 
  :return: value of the var db
  """
- return ContainerUtil.decode_object(self._db.get(b""), self.__value_type)
+ return ContainerUtil.decode_object(
+ self._db.get(self._DUMMY_LAST_KEY),
+ self.__value_type
+ )
 
  def remove(self) -> None:
  """
  Deletes the value
  """
- self._db.delete(b"")
+ self._db.delete(self._DUMMY_LAST_KEY)
 
 
 def get_default_value(value_type: type) -> Any: