{
  "id": "python/pydantic-v2-field-required-missing",
  "signature": "pydantic_core._pydantic_core.ValidationError: 1 validation error for User\nname\n  Field required [type=missing, input_value={'age': 25}, input_type=dict]",
  "signature_zh": "pydantic_core._pydantic_core.ValidationError: 1 validation error for User\nname\n  字段必填 [type=missing, input_value={'age': 25}, input_type=dict]",
  "regex": "pydantic_core\\._pydantic_core\\.ValidationError:\\ 1\\ validation\\ error\\ for\\ User\\\nname\\\n\\ \\ Field\\ required\\ \\[type=missing,\\ input_value=\\{'age':\\ 25\\},\\ input_type=dict\\]",
  "domain": "python",
  "category": "data_error",
  "subcategory": null,
  "root_cause": "A required field was omitted from the input data. In Pydantic v2, fields without a default are mandatory, and passing a dict that lacks them raises a missing-field ValidationError.",
  "root_cause_type": "generic",
  "root_cause_zh": "输入数据中缺少了必填字段。在 Pydantic v2 中，没有默认值的字段是必填的，传入缺少该字段的字典会抛出 missing 类型的 ValidationError。",
  "versions": [
    {
      "version": "2.x",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "",
      "why_fails": "Hides the real data problem; downstream code receives an incomplete or default object and fails later with confusing AttributeError",
      "fail_rate": 0.75,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "extra='allow' only affects unexpected fields, not missing required ones; the ValidationError persists",
      "fail_rate": 0.9,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "",
      "success_rate": 0.95,
      "how": "Provide a default value: `name: str = ''` or `name: str = Field(default='unknown')`. Use `Optional[str] = None` if the field is genuinely optional.",
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "success_rate": 0.88,
      "how": "Use model_validate with a pre-filled dict: `User.model_validate({'name': 'anon', **input_data})` so missing keys fall back to defaults.",
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "success_rate": 0.7,
      "how": "Validate partial data with `User.model_construct(**input_data)` when you only need a best-effort object without validation.",
      "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": 0.88,
  "fix_success_rate": 0.8,
  "resolvable": "true",
  "first_seen": "2024-03-12",
  "last_confirmed": "2025-01-01",
  "last_updated": "2025-01-01",
  "evidence_count": 0,
  "tags": [],
  "locale": "en",
  "aliases": []
}