fix: avoid pickling vertex component instances (#13172)

* Avoid pickling vertex component runtime state

* Add docstrings for vertex serialization regression helper

---------

Co-authored-by: Gabriel Luiz Freitas Almeida <gabriel@logspace.ai>

src/lfx/src/lfx/graph/vertex/base.py

@@ -227,6 +227,7 @@ class Vertex:
     def __getstate__(self):
         state = self.__dict__.copy()
         state["_lock"] = None  # Locks are not serializable
+        state["custom_component"] = None  # Component instances are rebuilt and may hold non-serializable runtime state
         state["built_object"] = None if isinstance(self.built_object, UnbuiltObject) else self.built_object
         state["built_result"] = None if isinstance(self.built_result, UnbuiltResult) else self.built_result
         return state

src/lfx/tests/unit/graph/vertex/test_vertex_base.py

@@ -4,6 +4,7 @@ This module contains tests for verifying the functionality of the ParameterHandl
 which is responsible for processing and managing parameters in vertices.
 """
 
+import pickle
 from unittest.mock import Mock
 from uuid import uuid4
 
@@ -18,6 +19,29 @@ from lfx.services.storage.service import StorageService
 from lfx.utils.util import unescape_string
 
 
+def test_vertex_getstate_drops_custom_component_runtime_state():
+    """Graph cache serialization should rebuild component instances instead of pickling live runtime state."""
+
+    class UnpickleableComponent:
+        """Component stand-in that fails if live runtime state is serialized."""
+
+        def __getstate__(self):
+            """Raise when pickle tries to serialize the component instance."""
+            msg = "cannot pickle component runtime state"
+            raise TypeError(msg)
+
+    vertex = object.__new__(Vertex)
+    vertex._lock = Mock()
+    vertex.custom_component = UnpickleableComponent()
+    vertex.built_object = object()
+    vertex.built_result = object()
+
+    state = vertex.__getstate__()
+
+    assert state["custom_component"] is None
+    pickle.dumps(state)
+
+
 @pytest.fixture
 def mock_storage_service() -> Mock:
     """Create a mock storage service for testing."""