CODEWITHSUNDEEP
pythonpydantic
Kevad
Kevad

Reputation: 2991

pydantic's `Field`'s default value ignores constraint checks

from pydantic import BaseModel

class User(BaseModel):
  age: int = Field('foo', ge=0)


User()  # doesn't raise an error
# User(age='foo')

Why doesn't this raise an error since a string foo is passed even though an int is expected?

User(age='foo') however raises the ValidationError as expected.

Upvotes: 1

Views: 755

Answers (1)

tstorek
tstorek

Reputation: 66

This connected to the config that you can add to all of your models. By default the default of Fields are excluding from validation, simply assuming that the programmer puts a proper default value. However, if you want to enforce validation you cann enforce it by adding a Config to your model:

class User(BaseModel):
  age: int = Field('foo', ge=0)

  class Config(BaseConfig):
      validate_all = True


if __name__ == "__main__":
    User()  # Now raise an error

Also have a look at the other options for configs in the the docs: https://pydantic-docs.helpmanual.io/usage/model_config/

Upvotes: 3

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