8000 fix: use dataclasses proxy for frozen or empty dataclasses (#4878) · pydantic/pydantic@bf4b5ce · GitHub
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PrettyWoodPrettyWood
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fix: use dataclasses proxy for frozen or empty dataclasses (#4878)
* add tests * fix: dataclasses * chore: add change file * refactor: remove useless kwarg * test: add new test * keep old kwarg to avoid breaking change
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‎changes/4878-PrettyWood.md

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fix: use dataclass proxy for frozen or empty dataclasses

‎pydantic/dataclasses.py

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Original file line numberDiff line numberDiff line change
@@ -34,20 +34,7 @@ class M:
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import sys
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from contextlib import contextmanager
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from functools import wraps
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from typing import (
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TYPE_CHECKING,
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Any,
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Callable,
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ClassVar,
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Dict,
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Generator,
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Optional,
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Set,
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Type,
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TypeVar,
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Union,
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overload,
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)
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from typing import TYPE_CHECKING, Any, Callable, ClassVar, Dict, Generator, Optional, Type, TypeVar, Union, overload
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from typing_extensions import dataclass_transform
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@@ -117,6 +104,7 @@ def dataclass(
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frozen: bool = False,
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config: Union[ConfigDict, Type[object], None] = None,
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validate_on_init: Optional[bool] = None,
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use_proxy: Optional[bool] = None,
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kw_only: bool = ...,
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) -> Callable[[Type[_T]], 'DataclassClassOrWrapper']:
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...
@@ -134,6 +122,7 @@ def dataclass(
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frozen: bool = False,
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config: Union[ConfigDict, Type[object], None] = None,
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validate_on_init: Optional[bool] = None,
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use_proxy: Optional[bool] = None,
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kw_only: bool = ...,
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) -> 'DataclassClassOrWrapper':
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...
@@ -152,6 +141,7 @@ def dataclass(
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frozen: bool = False,
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config: Union[ConfigDict, Type[object], None] = None,
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validate_on_init: Optional[bool] = None,
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use_proxy: Optional[bool] = None,
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) -> Callable[[Type[_T]], 'DataclassClassOrWrapper']:
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...
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@@ -168,6 +158,7 @@ def dataclass(
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frozen: bool = False,
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config: Union[ConfigDict, Type[object], None] = None,
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validate_on_init: Optional[bool] = None,
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use_proxy: Optional[bool] = None,
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) -> 'DataclassClassOrWrapper':
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...
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@@ -184,6 +175,7 @@ def dataclass(
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frozen: bool = False,
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config: Union[ConfigDict, Type[object], None] = None,
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validate_on_init: Optional[bool] = None,
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use_proxy: Optional[bool] = None,
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kw_only: bool = False,
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) -> Union[Callable[[Type[_T]], 'DataclassClassOrWrapper'], 'DataclassClassOrWrapper']:
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"""
@@ -197,7 +189,15 @@ def dataclass(
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def wrap(cls: Type[Any]) -> 'DataclassClassOrWrapper':
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import dataclasses
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200-
if is_builtin_dataclass(cls) and _extra_dc_args(_cls) == _extra_dc_args(_cls.__bases__[0]): # type: ignore
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should_use_proxy = (
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use_proxy
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if use_proxy is not None
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else (
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is_builtin_dataclass(cls)
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and (cls.__bases__[0] is object or set(dir(cls)) == set(dir(cls.__bases__[0])))
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)
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)
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if should_use_proxy:
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dc_cls_doc = ''
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dc_cls = DataclassProxy(cls)
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default_validate_on_init = False
@@ -437,14 +437,6 @@ def _dataclass_validate_assignment_setattr(self: 'Dataclass', name: str, value:
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object.__setattr__(self, name, value)
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439439

440-
def _extra_dc_args(cls: Type[Any]) -> Set[str]:
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return {
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x
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for x in dir(cls)
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if x not in getattr(cls, '__dataclass_fields__', {}) and not (x.startswith('__') and x.endswith('__'))
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}
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def is_builtin_dataclass(_cls: Type[Any]) -> bool:
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"""
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Whether a class is a stdlib dataclass
@@ -482,4 +474,4 @@ def make_dataclass_validator(dc_cls: Type['Dataclass'], config: Type[BaseConfig]
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and yield the validators
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It retrieves the parameters of the dataclass and forwards them to the newly created dataclass
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"""
485-
yield from _get_validators(dataclass(dc_cls, config=config, validate_on_init=False))
477+
yield from _get_validators(dataclass(dc_cls, config=config, use_proxy=True))

‎tests/test_dataclasses.py

Lines changed: 95 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1513,3 +1513,98 @@ class Foo:
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assert config.bar == 'cat'
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setattr(config, 'bar', 'dog')
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assert config.bar == 'dog'
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def test_frozen_dataclasses():
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@dataclasses.dataclass(frozen=True)
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class First:
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a: int
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@dataclasses.dataclass(frozen=True)
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class Second(First):
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@property
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def b(self):
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return self.a
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class My(BaseModel):
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my: Second
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assert My(my=Second(a='1')).my.b == 1
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def test_empty_dataclass():
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"""should be able to inherit without adding a field"""
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@dataclasses.dataclass
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class UnvalidatedDataclass:
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a: int = 0
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1542+
@pydantic.dataclasses.dataclass
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class ValidatedDerivedA(UnvalidatedDataclass):
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...
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@pydantic.dataclasses.dataclass()
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class ValidatedDerivedB(UnvalidatedDataclass):
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b: int = 0
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1550+
@pydantic.dataclasses.dataclass()
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class ValidatedDerivedC(UnvalidatedDataclass):
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...
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1554+
1555+
def test_proxy_dataclass():
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@dataclasses.dataclass
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class Foo:
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a: Optional[int] = dataclasses.field(default=42)
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b: List = dataclasses.field(default_factory=list)
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1561+
@dataclasses.dataclass
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class Bar:
1563+
pass
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1565+
@dataclasses.dataclass
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class Model1:
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foo: Foo
1568+
1569+
class Model2(BaseModel):
1570+
foo: Foo
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1572+
m1 = Model1(foo=Foo())
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m2 = Model2(foo=Foo())
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1575+
assert m1.foo.a == m2.foo.a == 42
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assert m1.foo.b == m2.foo.b == []
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assert m1.foo.Bar() is not None
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assert m2.foo.Bar() is not None
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1581+
def test_proxy_dataclass_2():
1582+
@dataclasses.dataclass
1583+
class M1:
1584+
a: int
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b: str = 'b'
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c: float = dataclasses.field(init=False)
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1588+
def __post_init__(self):
1589+
self.c = float(self.a)
1590+
1591+
@dataclasses.dataclass
1592+
class M2:
1593+
a: int
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b: str = 'b'
1595+
c: float = dataclasses.field(init=False)
1596+
1597+
def __post_init__(self):
1598+
self.c = float(self.a)
1599+
1600+
@pydantic.validator('b')
1601+
def check_b(cls, v):
1602+
if not v:
1603+
raise ValueError('b should not be empty')
1604+
return v
1605+
1606+
m1 = pydantic.parse_obj_as(M1, {'a': 3})
1607+
m2 = pydantic.parse_obj_as(M2, {'a': 3})
1608+
assert m1.a == m2.a == 3
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assert m1.b == m2.b == 'b'
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assert m1.c == m2.c == 3.0

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