fix: handle explicit null values in Config.get

nnote/config.py

@@ -44,14 +44,16 @@ def save(self) -> None:
         with self._path.open("w", encoding="utf-8") as f:
             yaml.dump(self._data, f, default_flow_style=False, allow_unicode=True)
 
+    _MISSING = object()
+
     def get(self, *keys: str, default: Any = None) -> Any:
         """Retrieve a nested value by key path, returning default if missing."""
         node = self._data
         for key in keys:
             if not isinstance(node, dict):
                 return default
-            node = node.get(key, default)
-            if node is default:
+            node = node.get(key, self._MISSING)
+            if node is self._MISSING:
                 return default
         return node
 

tests/test_config.py

@@ -40,6 +40,14 @@ def test_get_missing_key_returns_default(tmp_path):
     assert config.get("missing", default="fallback") == "fallback"
 
 
+def test_get_explicit_null_value(tmp_path):
+    cfg_file = tmp_path / "config.yaml"
+    cfg_file.write_text("key: null\n")
+    config = Config.load(cfg_file)
+    assert config.get("key") is None
+    assert config.get("key", default="fallback") is None
+
+
 def test_get_nested_key(tmp_path):
     cfg_file = tmp_path / "config.yaml"
     cfg_file.write_text("a:\n  b: value\n")