python type_error ai_generated true

pydantic_core._pydantic_core.ValidationError: 1 validation error for Payload name Input should be a valid string [type=string_type, input_value=123, input_type=int]

ID: python/pydantic-strict-str-from-int

Also available as: JSON · Markdown · 中文
80%Fix Rate
86%Confidence
0Evidence
2024-06-02First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
2.x active — — —

Root Cause

model_config strict=True (or StrictStr) prevents coercion of int to str, even though v1 allowed it.

generic

中文

model_config 的 strict=True（或 StrictStr）阻止将 int 强制转换为 str，尽管 v1 允许这样做。

Workarounds

  1. 90% success 
    from pydantic import BaseModel, field_validator
class Payload(BaseModel):
    model_config = {'strict': True}
    name: str
    @field_validator('name', mode='before')
    @classmethod
    def to_str(cls, v):
        return str(v)
  2. 85% success 
    class Payload(BaseModel):
    name: int | str
    @field_validator('name')
    @classmethod
    def norm(cls, v): return str(v)

Dead Ends

Common approaches that don't work:

  1. 40% fail

    Changes semantics only for that field; other numeric-to-string coercions still fail.

  2. 50% fail

    Every caller must remember; easy to miss in one code path.

  3. 55% fail

    Disables strictness everywhere, re-introducing silent coercions you wanted to avoid.