Split public and private config/driver APIs (#6024)

redbot/core/_config.py

@@ -0,0 +1,26 @@
+import weakref
+from typing import Tuple, Type
+
+from redbot.core.config import Config, _config_cache
+from redbot.core._drivers import BaseDriver
+
+__all__ = ("get_latest_confs", "migrate")
+
+_retrieved = weakref.WeakSet()
+
+
+def get_latest_confs() -> Tuple[Config, ...]:
+    global _retrieved
+    ret = set(_config_cache.values()) - set(_retrieved)
+    _retrieved |= ret
+    return tuple(ret)
+
+
+async def migrate(cur_driver_cls: Type[BaseDriver], new_driver_cls: Type[BaseDriver]) -> None:
+    """Migrate from one driver type to another."""
+    # Get custom group data
+    core_conf = Config.get_core_conf(allow_old=True)
+    core_conf.init_custom("CUSTOM_GROUPS", 2)
+    all_custom_group_data = await core_conf.custom("CUSTOM_GROUPS").all()
+
+    await cur_driver_cls.migrate_to(new_driver_cls, all_custom_group_data)