fix(config): reject empty override keys (#883)

Author: CodingFeng101

src/minisweagent/config/__init__.py

@@ -42,6 +42,8 @@ def _key_value_spec_to_nested_dict(config_spec: str) -> dict:
     except json.JSONDecodeError:
         pass
     keys = key.split(".")
+    if any(k == "" for k in keys):
+        raise ValueError(f"Invalid config spec {config_spec!r}: empty config key")
     result = {}
     current = result
     for k in keys[:-1]:

tests/config/test_init.py

@@ -83,6 +83,11 @@ def test_zero_integer(self):
     def test_zero_float(self):
         assert _key_value_spec_to_nested_dict("value=0.0") == {"value": 0.0}
 
+    @pytest.mark.parametrize("config_spec", ["=value", "model..name=value", "model.=value"])
+    def test_empty_key_raises_value_error(self, config_spec):
+        with pytest.raises(ValueError, match="empty config key"):
+            _key_value_spec_to_nested_dict(config_spec)
+
 
 class TestGetConfigFromSpec:
     """Tests for get_config_from_spec function."""