{
  "id": "python/pydantic-recursion-depth",
  "signature": "pydantic_core._pydantic_core.ValidationError: 1 validation error for Node\nchild\n  Recursion error - maximum recursion depth exceeded [type=recursion_loop, input_value={...}, input_type=dict]",
  "signature_zh": "pydantic_core._pydantic_core.ValidationError：1 个验证错误（Node）\nchild\n  递归错误——超过最大递归深度 [type=recursion_loop, input_value={...}, input_type=dict]",
  "regex": "pydantic_core\\._pydantic_core\\.ValidationError:\\ 1\\ validation\\ error\\ for\\ Node\\\nchild\\\n\\ \\ Recursion\\ error\\ \\-\\ maximum\\ recursion\\ depth\\ exceeded\\ \\[type=recursion_loop,\\ input_value=\\{\\.\\.\\.\\},\\ input_type=dict\\]",
  "domain": "python",
  "category": "runtime_error",
  "subcategory": null,
  "root_cause": "A self-referential model (e.g., Node.child: Node) received a cyclic input dict, so validation loops forever.",
  "root_cause_type": "generic",
  "root_cause_zh": "自引用模型（如 Node.child: Node）接收到循环的输入字典，导致验证陷入无限循环。",
  "versions": [
    {
      "version": "2.x",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "",
      "why_fails": "Turns the loop into a segfault instead of a clean ValidationError.",
      "fail_rate": 0.75,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "Disables nested validation entirely; malformed children pass silently.",
      "fail_rate": 0.55,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "The error is raised as ValidationError; the except clause never fires.",
      "fail_rate": 0.5,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "",
      "success_rate": 0.9,
      "how": "def has_cycle(d, seen=None):\n    seen = seen or set()\n    if id(d) in seen: return True\n    seen.add(id(d))\n    return any(has_cycle(v, seen) for v in d.values() if isinstance(v, dict))\nassert not has_cycle(payload)",
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "success_rate": 0.8,
      "how": "from pydantic import BaseModel, model_validator\nclass Node(BaseModel):\n    child: 'Node | None' = None\n    @model_validator(mode='before')\n    @classmethod\n    def depth_guard(cls, v, info):\n        d = info.context.get('depth', 0) if info.context else 0\n        if d > 50: raise ValueError('too deep')\n        return v",
      "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": 0.82,
  "fix_success_rate": 0.8,
  "resolvable": "partial",
  "first_seen": "2024-08-14",
  "last_confirmed": "2025-01-01",
  "last_updated": "2025-01-01",
  "evidence_count": 0,
  "tags": [],
  "locale": "en",
  "aliases": []
}