{"record":{"id":"e245076acea3e81d","repo":"langchain-ai/langgraph","slug":"cannot-copy-a-non-existent-checkpoint","errorCode":null,"errorMessage":"Cannot copy a non-existent checkpoint","messagePattern":"Cannot copy a non-existent checkpoint","errorType":"exception","errorClass":"InvalidUpdateError","httpStatus":null,"severity":"error","filePath":"libs/langgraph/langgraph/pregel/main.py","lineNumber":1807,"sourceCode":"                    )\n\n                    return patch_checkpoint_map(\n                        next_config, saved.metadata if saved else None\n                    )\n                else:\n                    raise InvalidUpdateError(\n                        f\"Received no input writes for {self.input_channels}\"\n                    )\n\n            # copy checkpoint\n            if as_node == \"__copy__\":\n                if len(updates) > 1:\n                    raise InvalidUpdateError(\n                        \"Cannot copy checkpoint with multiple updates\"\n                    )\n\n                if saved is None:\n                    raise InvalidUpdateError(\"Cannot copy a non-existent checkpoint\")\n\n                next_checkpoint = create_checkpoint(checkpoint, None, step)\n\n                # copy checkpoint\n                next_config = checkpointer.put(\n                    saved.parent_config\n                    or patch_configurable(\n                        saved.config, {CONFIG_KEY_CHECKPOINT_ID: None}\n                    ),\n                    next_checkpoint,\n                    {\n                        \"source\": \"fork\",\n                        \"step\": step + 1,\n                        \"parents\": saved.metadata.get(\"parents\", {}),\n                    },\n                    {},\n                )\n","sourceCodeStart":1789,"sourceCodeEnd":1825,"githubUrl":"https://github.com/langchain-ai/langgraph/blob/38031739e551638e373fb553453256c23feeb41f/libs/langgraph/langgraph/pregel/main.py#L1789-L1825","documentation":"Error \"Cannot copy a non-existent checkpoint\" thrown in langchain-ai/langgraph.","triggerScenarios":"Thrown at libs/langgraph/langgraph/pregel/main.py:1807 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"}