Do not raise an exception when a nested field is overriden by an environment variable while reading another nested sibling

Signed-off-by: Roman Kuzmenko <[email protected]>

Author: clairbee

vyper/vyper.py

@@ -324,8 +324,8 @@ def _set_insensitive(self, key, val, source):
         if source:
             real_key = self._find_real_key(key, source)
             if real_key is None:
-                msg = "No case insensitive variant of {0} found.".format(key)
-                raise KeyError(msg)
+                log.debug("No case insensitive variant of {0} found.".format(key))
+                return False
 
             source[real_key] = val
             return True