{
  "id": "python/pydantic-configerror-frozen-field-mutation",
  "signature": "pydantic_core._pydantic_core.ValidationError: 1 validation error for Settings\napi_key\n  Instance is frozen [type=frozen_instance, input_value='new-key', input_type=str]",
  "signature_zh": "pydantic_core._pydantic_core.ValidationError: 1 个验证错误，实例已冻结 [type=frozen_instance]",
  "regex": "pydantic_core\\._pydantic_core\\.ValidationError:\\ 1\\ validation\\ error\\ for\\ Settings\\\napi_key\\\n\\ \\ Instance\\ is\\ frozen\\ \\[type=frozen_instance,\\ input_value='new\\-key',\\ input_type=str\\]",
  "domain": "python",
  "category": "config_error",
  "subcategory": null,
  "root_cause": "A BaseSettings/BaseModel was declared with model_config = ConfigDict(frozen=True), and code attempted to assign a new value to a field after construction.",
  "root_cause_type": "generic",
  "root_cause_zh": "BaseSettings/BaseModel 声明了 model_config = ConfigDict(frozen=True)，代码在构造之后尝试给字段赋新值。",
  "versions": [
    {
      "version": "2.x",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "",
      "why_fails": "Bypassing Pydantic's __setattr__ works at runtime but leaves the model's internal __pydantic_fields_set__ inconsistent and can break serialization.",
      "fail_rate": 0.55,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "frozen models also block __delattr__, raising TypeError: cannot delete field.",
      "fail_rate": 0.9,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "",
      "success_rate": 0.95,
      "how": "new_settings = settings.model_copy(update={'api_key': 'new-key'})",
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "success_rate": 0.9,
      "how": "class Settings(BaseSettings):\n    model_config = ConfigDict(frozen=False)\n    api_key: str",
      "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": 0.89,
  "fix_success_rate": 0.8,
  "resolvable": "true",
  "first_seen": "2024-09-08",
  "last_confirmed": "2025-01-01",
  "last_updated": "2025-01-01",
  "evidence_count": 0,
  "tags": [],
  "locale": "en",
  "aliases": []
}