chore: import upstream snapshot with attribution

runtime/node/executor/passthrough_executor.py

@@ -0,0 +1,36 @@
+"""Passthrough node executor."""
+
+from typing import List
+
+from entity.configs import Node
+from entity.configs.node.passthrough import PassthroughConfig
+from entity.messages import Message, MessageRole
+from runtime.node.executor.base import NodeExecutor
+
+
+class PassthroughNodeExecutor(NodeExecutor):
+    """Forward input messages without modifications."""
+
+    def execute(self, node: Node, inputs: List[Message]) -> List[Message]:
+        if node.node_type != "passthrough":
+            raise ValueError(f"Node {node.id} is not a passthrough node")
+
+        config = node.as_config(PassthroughConfig)
+        if config is None:
+            raise ValueError(f"Node {node.id} missing passthrough configuration")
+
+        if not inputs:
+            warning_msg = f"Passthrough node '{node.id}' triggered without inputs"
+            self.log_manager.warning(warning_msg, node_id=node.id, details={"input_count": 0})
+            return [Message(content="", role=MessageRole.USER)]
+
+        if config.only_last_message:
+            if len(inputs) > 1:
+                self.log_manager.debug(
+                    f"Passthrough node '{node.id}' received {len(inputs)} inputs; forwarding the latest entry",
+                    node_id=node.id,
+                    details={"input_count": len(inputs)},
+                )
+            return [inputs[-1].clone()]
+        else:
+            return [msg.clone() for msg in inputs]