Bump Pydantic ♻️

Bump Pydantic is a tool to help you migrate your code from Pydantic V1 to V2.

Note If you find bugs, please report them on the issue tracker.

Table of contents

• Bump Pydantic ♻️
  • Table of contents
  • Installation
  • Usage
    • Check diff before applying changes
    • Apply changes
  • Rules
    • BP001: Add default None to Optional[T], Union[T, None] and Any fields
    • BP002: Replace Config class by model_config attribute
    • BP003: Replace Field old parameters to new ones
    • BP004: Replace imports
    • BP003: Replace Config class by model_config
    • BP005: Replace GenericModel by BaseModel
    • BP006: Replace __root__ by RootModel
    • BP007: Replace decorators
    • BP008: Replace pydantic.parse_obj_as by pydantic.TypeAdapter
  • License

Installation

The installation is as simple as:

pip install "bump-pydantic @ git+https://github.com/pydantic/bump-pydantic@main"

Usage

bump-pydantic is a CLI tool, hence you can use it from your terminal.

To see the available options, you can run:

bump-pydantic --help

Check diff before applying changes

To check the diff before applying the changes, you can run:

bump-pydantic --diff <package>

Apply changes

To apply the changes, you can run:

bump-pydantic <package>

Rules

You can find below the list of rules that are applied by bump-pydantic.

It's also possible to disable rules by using the --disable option.

BP001: Add default None to Optional[T], Union[T, None] and Any fields

• ✅ Add default None to Optional[T] fields.

The following code will be transformed:

class User(BaseModel):
    name: Optional[str]

Into:

class User(BaseModel):
    name: Optional[str] = None

BP002: Replace Config class by model_config attribute

• ✅ Replace Config class by model_config = ConfigDict().
• ✅ Rename old Config attributes to new model_config attributes.
• ✅ Add a TODO comment in case the transformation can't be done automatically.
• ✅ Replace Extra enum by string values.

The following code will be transformed:

from pydantic import BaseModel, Extra


class User(BaseModel):
    name: str

    class Config:
        extra = Extra.forbid

Into:

from pydantic import ConfigDict, BaseModel


class User(BaseModel):
    name: str

    model_config = ConfigDict(extra="forbid")

BP003: Replace Field old parameters to new ones

• ✅ Replace Field old parameters to new ones.
• ✅ Replace field: Enum = Field(Enum.VALUE, const=True) by field: Literal[Enum.VALUE] = Enum.VALUE.

The following code will be transformed:

from typing import List

from pydantic import BaseModel, Field


class User(BaseModel):
    name: List[str] = Field(..., min_items=1)

Into:

from typing import List

from pydantic import BaseModel, Field


class User(BaseModel):
    name: List[str] = Field(..., min_length=1)

BP004: Replace imports

• ✅ Replace BaseSettings from pydantic to pydantic_settings.
• ✅ Replace Color and PaymentCardNumber from pydantic to pydantic_extra_types.

BP003: Replace Config class by model_config

• ✅ Replace Config class by model_config = ConfigDict().

The following code will be transformed:

class User(BaseModel):
    name: str

    class Config:
        extra = 'forbid'

Into:

class User(BaseModel):
    name: str

    model_config = ConfigDict(extra='forbid')

BP005: Replace GenericModel by BaseModel

• ✅ Replace GenericModel by BaseModel.

The following code will be transformed:

from typing import Generic, TypeVar
from pydantic.generics import GenericModel

T = TypeVar('T')

class User(GenericModel, Generic[T]):
    name: str

Into:

from typing import Generic, TypeVar

T = TypeVar('T')

class User(BaseModel, Generic[T]):
    name: str

BP006: Replace __root__ by RootModel

• ✅ Replace __root__ by RootModel.

The following code will be transformed:

from typing import List

from pydantic import BaseModel

class User(BaseModel):
    age: int
    name: str

class Users(BaseModel):
    __root__ = List[User]

Into:

from typing import List

from pydantic import RootModel

class User(BaseModel):
    age: int
    name: str

class Users(RootModel[List[User]]):
    pass

BP007: Replace decorators

• ✅ Replace @validator by @field_validator.
• ✅ Replace @root_validator by @model_validator.

The following code will be transformed:

from pydantic import BaseModel, validator, root_validator


class User(BaseModel):
    name: str

    @validator('name', pre=True)
    def validate_name(cls, v):
        return v

    @root_validator(pre=True)
    def validate_root(cls, values):
        return values

Into:

from pydantic import BaseModel, field_validator, model_validator


class User(BaseModel):
    name: str

    @field_validator('name', mode='before')
    def validate_name(cls, v):
        return v

    @model_validator(mode='before')
    def validate_root(cls, values):
        return values

BP008: Replace pydantic.parse_obj_as by pydantic.TypeAdapter

• ✅ Replace pydantic.parse_obj_as(T, obj) to pydantic.TypeAdapter(T).validate_python(obj).

The following code will be transformed:

from typing import List

from pydantic import BaseModel, parse_obj_as


class User(BaseModel):
    name: str


class Users(BaseModel):
    users: List[User]


users = parse_obj_as(Users, {'users': [{'name': 'John'}]})

Into:

from typing import List

from pydantic import BaseModel, TypeAdapter


class User(BaseModel):
    name: str


class Users(BaseModel):
    users: List[User]


users = TypeAdapter(Users).validate_python({'users': [{'name': 'John'}]})

License

This project is licensed under the terms of the MIT license.