{"record":{"id":"ac21d4fa7a1ec14d","repo":"bytedance/deer-flow","slug":"failed-to-find-branch-checkpoint","errorCode":null,"errorMessage":"Failed to find branch checkpoint","messagePattern":"Failed to find branch checkpoint","errorType":"http","errorClass":"HTTPException","httpStatus":500,"severity":"error","filePath":"backend/app/gateway/routers/threads.py","lineNumber":214,"sourceCode":"\n\nasync def _find_branch_checkpoint(\n    accessor: Any,\n    config: dict[str, Any],\n    target_message_ids: set[str],\n) -> Any:\n    try:\n        for snapshot in await accessor.ahistory(config, limit=_BRANCH_HISTORY_RAW_SCAN_LIMIT):\n            if is_duration_only_checkpoint(snapshot):\n                continue\n            if _matches_branch_target(_checkpoint_messages(snapshot), target_message_ids):\n                return snapshot\n    except _CHECKPOINT_MODE_ERRORS as exc:\n        raise _checkpoint_mode_http_error(exc, config.get(\"configurable\", {}).get(\"thread_id\", \"\")) from exc\n    except Exception:\n        thread_id = config.get(\"configurable\", {}).get(\"thread_id\", \"\")\n        logger.exception(\"Failed to scan branch checkpoint history for thread %s\", sanitize_log_param(thread_id))\n        raise HTTPException(status_code=500, detail=\"Failed to find branch checkpoint\")\n    raise HTTPException(status_code=409, detail=\"This turn can no longer be branched from.\")\n\n\nasync def _branch_targets_latest_turn(\n    accessor: Any,\n    config: dict[str, Any],\n    target_message_ids: set[str],\n) -> bool:\n    \"\"\"Return whether the target turn is the final visible turn.\"\"\"\n    try:\n        for snapshot in await accessor.ahistory(config, limit=_BRANCH_HISTORY_RAW_SCAN_LIMIT):\n            if is_duration_only_checkpoint(snapshot):\n                continue\n            messages = _checkpoint_messages(snapshot)\n            if not messages:\n                continue\n            return _matches_branch_target(messages, target_message_ids)\n    except Exception:","sourceCodeStart":196,"sourceCodeEnd":232,"githubUrl":"https://github.com/bytedance/deer-flow/blob/1dd6ba1acb03700589994b0366c5d1c7d05e2eff/backend/app/gateway/routers/threads.py#L196-L232","documentation":"Error \"Failed to find branch checkpoint\" thrown in bytedance/deer-flow.","triggerScenarios":"Thrown at backend/app/gateway/routers/threads.py:214 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Refresh the thread; the checkpoint may have been superseded. Pick a current turn to branch from.","Check the Gateway logs for checkpoint read failures indicating storage issues."],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"1dd6ba1acb03700589994b0366c5d1c7d05e2eff","analyzedAt":"2026-08-14T21:20:34.804Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}