diff --git a/dbt_common/contracts/config/base.py b/dbt_common/contracts/config/base.py
index 65020a7..74e80dc 100644
--- a/dbt_common/contracts/config/base.py
+++ b/dbt_common/contracts/config/base.py
@@ -117,25 +117,27 @@ def same_contents(cls, unrendered: Dict[str, Any], other: Dict[str, Any]) -> boo
 
     @classmethod
     def update_from(
-        cls, dct: Dict[str, Any], data: Dict[str, Any], adapter_config_cls: Type[BaseConfig]
+        cls,
+        orig_dict: Dict[str, Any],
+        new_dict: Dict[str, Any],
+        adapter_config_cls: Type[BaseConfig],
     ) -> Dict[str, Any]:
         """Update and validate config given a dict.
 
         Given a dict of keys, update the current config from them, validate
         it, and return a new config with the updated values
         """
-        #       dct = self.to_dict(omit_none=False)
 
-        self_merged = cls._merge_dicts(dct, data)
-        dct.update(self_merged)
+        self_merged = cls._merge_dicts(orig_dict, new_dict)
+        new_dict.update(self_merged)
 
-        adapter_merged = adapter_config_cls._merge_dicts(dct, data)
-        dct.update(adapter_merged)
+        adapter_merged = adapter_config_cls._merge_dicts(orig_dict, new_dict)
+        new_dict.update(adapter_merged)
 
         # any remaining fields must be "clobber"
-        dct.update(data)
+        orig_dict.update(new_dict)
 
-        return dct
+        return orig_dict
 
     @classmethod
     def _merge_dicts(cls, src: Dict[str, Any], data: Dict[str, Any]) -> Dict[str, Any]: