{"record":{"id":"b1b843d979e62227","repo":"langchain-ai/langgraph","slug":"invalid-update-item-item-when-copying-checkpoin","errorCode":null,"errorMessage":"Invalid update item: {item} when copying checkpoint","messagePattern":"Invalid update item: (.+?) when copying checkpoint","errorType":"exception","errorClass":"InvalidUpdateError","httpStatus":null,"severity":"error","filePath":"libs/langgraph/langgraph/pregel/main.py","lineNumber":1853,"sourceCode":"                        managed,\n                        next_config,\n                        step + 2,\n                        step + 4,\n                        for_execution=True,\n                        store=self.store,\n                        checkpointer=checkpointer,\n                        manager=None,\n                    )\n\n                    tasks_group_by = defaultdict(list)\n                    user_group_by: dict[str, list[StateUpdate]] = defaultdict(list)\n\n                    for task in next_tasks.values():\n                        tasks_group_by[task.name].append(task.id)\n\n                    for item in values:\n                        if not isinstance(item, Sequence):\n                            raise InvalidUpdateError(\n                                f\"Invalid update item: {item} when copying checkpoint\"\n                            )\n\n                        values, as_node = item[:2]\n\n                        user_group = user_group_by[as_node]\n                        tasks_group = tasks_group_by[as_node]\n\n                        target_idx = len(user_group)\n                        task_id = (\n                            tasks_group[target_idx]\n                            if target_idx < len(tasks_group)\n                            else None\n                        )\n\n                        user_group_by[as_node].append(\n                            StateUpdate(values=values, as_node=as_node, task_id=task_id)\n                        )","sourceCodeStart":1835,"sourceCodeEnd":1871,"githubUrl":"https://github.com/langchain-ai/langgraph/blob/38031739e551638e373fb553453256c23feeb41f/libs/langgraph/langgraph/pregel/main.py#L1835-L1871","documentation":"Error \"Invalid update item: {item} when copying checkpoint\" thrown in langchain-ai/langgraph.","triggerScenarios":"Thrown at libs/langgraph/langgraph/pregel/main.py:1853 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"38031739e551638e373fb553453256c23feeb41f","analyzedAt":"2026-08-26T18:02:49.312Z","schemaVersion":2},"datasetVersion":"2026-08-26T21:11:00.512Z"}