[V3 Config] Implement a true clear method (#1344)

* Add clear methods to drivers

* Update config clear methods, add to Value

* Add test

redbot/core/drivers/red_base.py

@@ -1,5 +1,3 @@
-from typing import Tuple
-
 __all__ = ["BaseDriver"]
 
 
@@ -8,13 +6,18 @@ class BaseDriver:
         self.cog_name = cog_name
         self.unique_cog_identifier = None  # This is set by Config's init method
 
-    async def get(self, *identifiers: Tuple[str]):
+    async def get(self, *identifiers: str):
         """
         Finds the value indicate by the given identifiers.
 
-        :param identifiers:
+        Parameters
+        ----------
+        identifiers
             A list of identifiers that correspond to nested dict accesses.
-        :return:
+
+        Returns
+        -------
+        Any
             Stored value.
         """
         raise NotImplementedError
@@ -24,18 +27,34 @@ class BaseDriver:
         Asks users for additional configuration information necessary
         to use this config driver.
 
-        :return:
+        Returns
+        -------
             Dict of configuration details.
         """
         raise NotImplementedError
 
-    async def set(self, *identifiers: Tuple[str], value=None):
+    async def set(self, *identifiers: str, value=None):
         """
         Sets the value of the key indicated by the given identifiers.
 
-        :param identifiers:
+        Parameters
+        ----------
+        identifiers
             A list of identifiers that correspond to nested dict accesses.
-        :param value:
+        value
             Any JSON serializable python object.
         """
         raise NotImplementedError
+
+    async def clear(self, *identifiers: str):
+        """
+        Clears out the value specified by the given identifiers.
+
+        Equivalent to using ``del`` on a dict.
+
+        Parameters
+        ----------
+        identifiers
+            A list of identifiers that correspond to nested dict accesses.
+        """
+        raise NotImplementedError

redbot/core/drivers/red_json.py

@@ -58,3 +58,14 @@ class JSON(BaseDriver):
 
         partial[full_identifiers[-1]] = value
         await self.jsonIO._threadsafe_save_json(self.data)
+
+    async def clear(self, *identifiers: str):
+        partial = self.data
+        full_identifiers = (self.unique_cog_identifier, *identifiers)
+        for i in full_identifiers[:-1]:
+            if i not in partial:
+                break
+            partial = partial[i]
+        else:
+            del partial[identifiers[-1]]
+        await self.jsonIO._threadsafe_save_json(self.data)

redbot/core/drivers/red_mongo.py

@@ -71,7 +71,7 @@ class Mongo(BaseDriver):
         uuid, identifiers = identifiers[0], identifiers[1:]
         return uuid, identifiers
 
-    async def get(self, *identifiers: Tuple[str]):
+    async def get(self, *identifiers: str):
         await self._ensure_connected()
 
         mongo_collection = self.get_collection()
@@ -104,6 +104,17 @@ class Mongo(BaseDriver):
             upsert=True
         )
 
+    async def clear(self, *identifiers: str):
+        await self._ensure_connected()
+
+        dot_identifiers = '.'.join(identifiers)
+        mongo_collection = self.get_collection()
+
+        await mongo_collection.update_one(
+            {'_id': self.unique_cog_identifier},
+            update={"$unset": {dot_identifiers: 1}}
+        )
+
 
 def get_config_details():
     host = input("Enter host address: ")