Declare ObjectState parent forwarding state

Author: trissim

src/objectstate/object_state.py

@@ -225,6 +225,8 @@ def __init__(
         # === Flags (kept for batch operations) ===
         self._in_reset = False
         self._block_cross_window_updates = False
+        self._forwarding_to_parent = False
+        self._parent_field_name: Optional[str] = None
 
         # === State Change Callbacks ===
         # Callbacks notified when materialized state changes (dirty/signature diffs)
@@ -340,6 +342,12 @@ def _check_and_sync_delegate(self) -> bool:
 
         return True
 
+    @property
+    def has_delegate(self) -> bool:
+        """Return whether this state extracts parameters through an object delegate."""
+
+        return self._delegate_attr is not None
+
     @property
     def saved_object(self) -> Any:
         """Get the saved baseline object with the correct type.
@@ -437,15 +445,15 @@ def on_child_changed(changed_paths):
             )
 
         # Reentrancy guard (pattern from ObjectState architectural fixes)
-        if getattr(self, '_forwarding_to_parent', False):
+        if self._forwarding_to_parent:
             logger.debug(f"[ObjectState] Reentrancy guard blocked for {self.scope_id}")
             return
 
         self._forwarding_to_parent = True
         try:
             # Determine which parent field changed
             # Priority: explicit field_path arg > _parent_field_name > auto-detect
-            parent_field = field_path or getattr(self, '_parent_field_name', None)
+            parent_field = field_path or self._parent_field_name
             if parent_field is None:
                 # Auto-detect from scope: step::function_0 → 'function'
                 parts = self.scope_id.split('::')
@@ -1258,8 +1266,6 @@ def reset_parameter(self, param_name: str) -> None:
         default_value = self._signature_defaults.get(param_name)
         self.update_parameter(param_name, default_value)
 
-
-
     def get_current_values(self) -> Dict[str, Any]:
         """
         Get current parameter values from state.