{"record":{"id":"04a65ab291e0aa95","repo":"BigPizzaV3/CodexPlusPlus","slug":"canvas-user-04a65a","errorCode":null,"errorMessage":"历史消息分页游标重复","messagePattern":"历史消息分页游标重复","errorType":"exception","errorClass":"Error","httpStatus":null,"severity":"error","filePath":"tools/conversation-canvas/public/canvas.user.js","lineNumber":425,"sourceCode":"    for(const turn of page.data){\n      if(typeof turn.id!=='string')throw Error('历史轮次缺少 ID');\n      if(!turnIds.has(turn.id)){turnIds.add(turn.id);turns.push(turn);}\n    }\n    cursor=page.nextCursor??null;\n    onProgress(`正在读取轮次目录 · ${turns.length} 轮…`);\n  }while(cursor!==null);\n  const messages=[],seen=new Set();\n  for(const [index,turn] of turns.entries()){\n    signal?.throwIfAborted();onProgress(`正在读取历史 ${index+1}/${turns.length}…`);\n    const key=`${threadId}:${turn.id}`,cached=await cache.get(key);\n    let parsed;\n    if(cached&&turn.status==='completed')parsed=cached;\n    else{\n      const partial=turn.status==='completed'?await cache.get(`${key}:partial`):null;\n      parsed=partial?.messages?.slice()||[];let itemCursor=partial?.cursor??null,limit=32;const cursors=new Set();\n      do{\n        signal?.throwIfAborted();\n        if(cursors.has(itemCursor))throw Error('历史消息分页游标重复');\n        let page;\n        for(;;){\n          try{page=await send('thread/items/list',{threadId,turnId:turn.id,cursor:itemCursor,limit,sortDirection:'asc'});break;}\n          catch(error){\n            if(limit>1&&/decoded message length too large/i.test(error.message)){limit=Math.max(1,Math.floor(limit/2));continue;}\n            throw error;\n          }\n        }\n        if(!Array.isArray(page?.data))throw Error('历史消息接口返回格式无效');\n        cursors.add(itemCursor);\n        for(const row of page.data){\n          if(row.turnId!=null&&row.turnId!==turn.id)throw Error('历史消息所属轮次不匹配');\n          const item=row.item??row;\n          if(!['userMessage','agentMessage'].includes(item.type))continue;\n          if(typeof item.id!=='string')throw Error('历史消息缺少稳定 ID');\n          const role=item.type==='userMessage'?'user':'assistant';\n          const content=role==='user'?(item.content??[]):[{text:item.text??''}];\n          const message=parseMessage({type:'response_item',payload:{type:'message',id:item.id,role,phase:role==='assistant'?(item.phase??'final_answer'):'',content}},item.id);","sourceCodeStart":407,"sourceCodeEnd":443,"githubUrl":"https://github.com/BigPizzaV3/CodexPlusPlus/blob/b1ed92e5e4a2d74095d4b8db5af43cef7acba9c6/tools/conversation-canvas/public/canvas.user.js#L407-L443","documentation":"While fetching all items of a historical turn, the script loops 'thread/items/list' with a cursor and tracks every cursor seen in a Set; if the server returns a nextCursor equal to one already processed, the loop would be infinite, so it throws this guard error.","triggerScenarios":"A 'thread/items/list' response whose nextCursor points back to an already-used cursor value (including a repeated non-null cursor), producing a pagination cycle for that turn.","commonSituations":"Codex backend pagination bug after version upgrade; corrupted thread store returning stale cursors; transient server state during concurrent writes to the same thread.","solutions":["Update canvas.user.js to match the installed Codex version.","Retry after reloading the thread — if the cursor cycle was transient, a fresh pagination run may succeed.","Clear/rebuild the local thread cache entry (`${key}:partial`) so pagination restarts from a null cursor.","Patch the loop to reset itemCursor to null (or bail gracefully) instead of throwing when a cycle is detected."],"exampleFix":"// before\nif(cursors.has(itemCursor))throw Error('历史消息分页游标重复');\n// after\nif(cursors.has(itemCursor)){console.warn('cursor cycle detected, stopping');itemCursor=null;continue;}","handlingStrategy":"retry","validationCode":"// no pre-call check possible; guard is on server-returned cursor\ncursors=new Set();","typeGuard":"const isFreshCursor=(c,seen)=>c==null||!seen.has(c);","tryCatchPattern":"try{await importTurnItems(turn);}catch(e){if(e.message==='历史消息分页游标重复'){cache.delete(`${key}:partial`);return importTurnItems(turn);}throw e;}","preventionTips":["Clear partial cache after Codex upgrades","Avoid importing history while the thread is being written","Cap retry attempts when pagination cycles","Track cursor sets across retries to detect persistent server bugs"],"tags":["pagination","infinite-loop-guard","history-import"],"backgroundTag":"unexpected-response-shape","analyzedSha":"b1ed92e5e4a2d74095d4b8db5af43cef7acba9c6","analyzedAt":"2026-09-19T23:35:21.129Z","contentChangedAt":"2026-09-19T23:35:21.129Z","schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}