fix: ExportMixin captures only outermost __init__ args for correct export/rebuild round-trips

plugboard/utils/export_mixin.py

@@ -32,13 +32,24 @@ def _save_args_wrapper(method: _t.Callable, key: str) -> _t.Callable:
             for k, p in inspect.signature(method).parameters.items()
             if p.kind == inspect.Parameter.POSITIONAL_OR_KEYWORD and k != "self"
         ]
+        _reentrant_key = f"__{key}_active__"
 
         @wraps(method)
         def _wrapper(self: _t.Any, *args: _t.Any, **kwargs: _t.Any) -> None:
-            saved_kwargs = ExportMixin._convert_exportable_objs(kwargs)
-            saved_args = dict(zip(_positional_args[: len(args)], args))
-            setattr(self, key, {**getattr(self, key, {}), **saved_args, **saved_kwargs})
-            method(self, *args, **kwargs)
+            is_outermost = not getattr(self, _reentrant_key, False)
+            if is_outermost:
+                setattr(self, _reentrant_key, True)
+                saved_kwargs = ExportMixin._convert_exportable_objs(kwargs)
+                saved_args = dict(zip(_positional_args[: len(args)], args))
+                setattr(self, key, {**saved_args, **saved_kwargs})
+            try:
+                method(self, *args, **kwargs)
+            finally:
+                if is_outermost:
+                    try:
+                        delattr(self, _reentrant_key)
+                    except AttributeError:
+                        pass
 
         return _wrapper
 

tests/unit/test_component.py

@@ -68,6 +68,45 @@ async def test_component_initial_values(initial_values: dict[str, _t.Iterable])
     await component.io.close()
 
 
+class ExportBase(Component):
+    io = IO(inputs=[], outputs=["out"])
+
+    def __init__(self, x: int = 1, **kwargs: _t.Unpack[ComponentArgsDict]) -> None:
+        super().__init__(**kwargs)
+        self.x = x
+
+    async def step(self) -> None:
+        pass
+
+
+class ExportDerived(ExportBase):
+    io = IO(inputs=[], outputs=["out"])
+
+    def __init__(self, y: int = 2, **kwargs: _t.Unpack[ComponentArgsDict]) -> None:
+        super().__init__(x=y * 10, **kwargs)
+        self.y = y
+
+    async def step(self) -> None:
+        pass
+
+
+def test_export_captures_only_outermost_init_args() -> None:
+    """export() should record only the arguments passed to the outermost __init__."""
+    d = ExportDerived(name="d", y=3)
+    args = d.export()["args"]
+    # Only ExportDerived's own args should appear; ExportBase's derived 'x' must not
+    assert args == {"name": "d", "y": 3}
+    # Rebuilding from the exported args must succeed without TypeError
+    d2 = ExportDerived(**args)
+    assert d2.export()["args"] == args
+
+
+def test_export_no_stale_flag_on_instance() -> None:
+    """Re-entrancy flag must not persist on the instance after construction."""
+    d = ExportDerived(name="d", y=5)
+    assert not any(attr.endswith("_active__") for attr in vars(d))
+
+
 @pytest.mark.asyncio
 async def test_component_status() -> None:
     """Tests the status of a `Component` across its lifecycle."""