{"record":{"id":"e66a6069108bd43d","repo":"bytedance/deer-flow","slug":"expected-fact-fact-id-r-revision-expected-fact","errorCode":null,"errorMessage":"Expected fact {fact_id!r} revision {expected_fact_revision}, found {actual_fact_revision}","messagePattern":"Expected fact (.+?) revision (.+?), found (.+?)","errorType":"exception","errorClass":"MemoryFactRevisionConflict","httpStatus":null,"severity":"error","filePath":"backend/packages/harness/deerflow/agents/memory/backends/deermem/deermem/core/storage.py","lineNumber":752,"sourceCode":"        for incoming in upserts:\n            if not isinstance(incoming, dict):\n                raise ValueError(\"change_set.upserts must contain fact objects\")\n            candidate = copy.deepcopy(incoming)\n            candidate[\"id\"] = str(candidate.get(\"id\") or f\"fact_{uuid.uuid4().hex}\")\n            fact_id = candidate[\"id\"]\n            if fact_id in prepared:\n                raise ValueError(f\"Duplicate fact id {fact_id!r} in upserts\")\n            if agent_name is None:  # guarded above\n                raise ValueError(\"agent_name is required for fact repository changes\")\n            existing, fact_path = self._read_fact(path, fact_id, user_id=user_id, agent_name=agent_name)\n            if upsert_revisions is not None and fact_id in upsert_revisions:\n                expected_fact_revision = upsert_revisions[fact_id]\n                if expected_fact_revision is None and existing is not None:\n                    raise MemoryFactRevisionConflict(f\"Fact {fact_id!r} must not already exist\")\n                if expected_fact_revision is not None:\n                    actual_fact_revision = None if existing is None else existing.get(\"revision\")\n                    if actual_fact_revision != expected_fact_revision:\n                        raise MemoryFactRevisionConflict(f\"Expected fact {fact_id!r} revision {expected_fact_revision}, found {actual_fact_revision}\")\n            normalized = _normalize_fact(candidate, scope=scope, existing=existing)\n            if existing != normalized:\n                prepared[fact_id] = (normalized, existing, fact_path)\n\n        delete_ids = [str(fact_id) for fact_id in deletes]\n        if len(delete_ids) != len(set(delete_ids)):\n            raise ValueError(\"Duplicate fact ids are not allowed in deletes\")\n        removals: dict[str, tuple[dict[str, Any], Path]] = {}\n        for fact_id in delete_ids:\n            if fact_id in prepared:\n                raise ValueError(f\"Fact {fact_id!r} cannot be upserted and deleted together\")\n            if agent_name is None:  # guarded above\n                raise ValueError(\"agent_name is required for fact repository changes\")\n            existing, fact_path = self._read_fact(path, fact_id, user_id=user_id, agent_name=agent_name)\n            if existing is None:\n                continue\n            if delete_revisions and fact_id in delete_revisions and delete_revisions[fact_id] != existing.get(\"revision\"):\n                raise MemoryFactRevisionConflict(f\"Expected fact {fact_id!r} revision {delete_revisions[fact_id]}, found {existing.get('revision')}\")","sourceCodeStart":734,"sourceCodeEnd":770,"githubUrl":"https://github.com/bytedance/deer-flow/blob/1dd6ba1acb03700589994b0366c5d1c7d05e2eff/backend/packages/harness/deerflow/agents/memory/backends/deermem/deermem/core/storage.py#L734-L770","documentation":"Error \"Expected fact {fact_id!r} revision {expected_fact_revision}, found {actual_fact_revision}\" thrown in bytedance/deer-flow.","triggerScenarios":"Thrown at backend/packages/harness/deerflow/agents/memory/backends/deermem/deermem/core/storage.py:752 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Re-read the fact and retry with its current revision (optimistic concurrency conflict).","If conflicts persist, serialize writers to this fact."],"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":"2026-08-15T17:31:12.345Z"}