python data_error ai_generated true

pydantic.error_wrappers.ValidationError: 1 validation error for User

ID: python/fastapi-pydantic-validationerror

Also available as: JSON · Markdown · 中文
80%Fix Rate
87%Confidence
0Evidence
2025-09-15First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
2.x active — — —
2.5.x active — — —

Root Cause

Data passed to a Pydantic model doesn't match its schema.

generic

中文

传递给 Pydantic 模型的数据与其模式不匹配。

Workarounds

  1. 95% success 
    User(name='John', age=30)  # age must be int
  2. 90% success 
    @field_validator('age')
def parse_age(cls, v):
    return int(v)

Dead Ends

Common approaches that don't work:

  1. 70% fail

    Only ignores extra fields, not type errors.

  2. 90% fail

    Same validation applies.