Move cast registry to instance variable

sanic/config.py

@@ -71,7 +71,6 @@ def add(self, cast: Callable[[str], Any]) -> None:
 
 
 class Config(dict):
-    __registry__ = CastRegistry((int, float, str_to_bool, str))
 
     ACCESS_LOG: bool
     AUTO_RELOAD: bool
@@ -112,6 +111,7 @@ def __init__(
         defaults = defaults or {}
         super().__init__({**DEFAULT_CONFIG, **defaults})
 
+        self._cast_registry = CastRegistry((int, float, str_to_bool, str))
         self._app = app
         self._LOGO = ""
 
@@ -238,7 +238,7 @@ def __init__(self, name) -> None:
 
             _, config_key = key.split(prefix, 1)
 
-            for converter in self.__registry__:
+            for converter in self._cast_registry:
                 try:
                     self[config_key] = converter(value)
                     break
@@ -321,4 +321,4 @@ def register_type(self, *cast: Callable[[str], Any]) -> None:
         correct type.
         """
         for item in cast:
-            self.__registry__.add(item)
+            self._cast_registry.add(item)

tests/test_config.py

@@ -152,7 +152,6 @@ def test_env_w_custom_converter():
     assert isinstance(app.config.TEST_ANSWER, UltimateAnswer)
     assert app.config.TEST_ANSWER.answer == 42
     del environ["SANIC_TEST_ANSWER"]
-    config.__registry__.remove(UltimateAnswer)
 
 
 def test_add_converter_multiple_times(caplog):
@@ -166,8 +165,7 @@ def converter():
         config.register_type(converter)
 
     assert ("sanic.error", logging.WARNING, message) in caplog.record_tuples
-    assert len(config.__registry__) == 5
-    config.__registry__.remove(converter)
+    assert len(config._cast_registry) == 5
 
 
 def test_load_from_file(app):