{
  "id": "go/goroutine-range-over-closed-channel",
  "signature": "panic: receive from closed channel (in range)",
  "signature_zh": "恐慌：从已关闭的通道接收（在range中）",
  "regex": "panic:\\ receive\\ from\\ closed\\ channel\\ \\(in\\ range\\)",
  "domain": "go",
  "category": "runtime_error",
  "subcategory": null,
  "root_cause": "Iterating over a channel with range after it has been closed; range receives zero values until channel is drained.",
  "root_cause_type": "generic",
  "root_cause_zh": "在通道关闭后使用range迭代；range会接收零值直到通道耗尽。",
  "versions": [
    {
      "version": "1.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "1.20",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "Using recover() to catch panic from zero value",
      "why_fails": "Range over closed channel doesn't panic; it returns zero values, which may cause logic errors.",
      "fail_rate": 0.9,
      "condition": "",
      "sources": []
    },
    {
      "action": "Checking channel length before range",
      "why_fails": "len(ch) doesn't indicate closed state; closed channel can have buffered data.",
      "fail_rate": 0.8,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Use for with ok pattern instead of range",
      "success_rate": 0.95,
      "how": "for {\n    val, ok := <-ch\n    if !ok {\n        break\n    }\n    // process val\n}",
      "condition": "",
      "sources": []
    },
    {
      "action": "Ensure channel is closed only after all sends are done",
      "success_rate": 0.9,
      "how": "var wg sync.WaitGroup\nfor i := 0; i < 5; i++ {\n    wg.Add(1)\n    go func() {\n        defer wg.Done()\n        ch <- i\n    }()\n}\nwg.Wait()\nclose(ch)\nfor val := range ch {\n    // process\n}",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": null,
  "official_doc_section": null,
  "error_code": null,
  "verification_tier": "ai_generated",
  "confidence": 0.84,
  "fix_success_rate": 0.8,
  "resolvable": "true",
  "first_seen": "2024-06-18",
  "last_confirmed": "2025-01-01",
  "last_updated": "2025-01-01",
  "evidence_count": 0,
  "tags": [],
  "locale": "en",
  "aliases": []
}