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Editing: fields.py
"""Defining fields on models.""" from __future__ import annotations as _annotations import dataclasses import inspect import sys import typing from copy import copy from dataclasses import Field as DataclassField from functools import cached_property from typing import Any, ClassVar from warnings import warn import annotated_types import typing_extensions from pydantic_core import PydanticUndefined from typing_extensions import Literal, TypeAlias, Unpack, deprecated from . import types from ._internal import _decorators, _fields, _generics, _internal_dataclass, _repr, _typing_extra, _utils from .aliases import AliasChoices, AliasPath from .config import JsonDict from .errors import PydanticUserError from .warnings import PydanticDeprecatedSince20 if typing.TYPE_CHECKING: from ._internal._repr import ReprArgs else: # See PyCharm issues https://youtrack.jetbrains.com/issue/PY-21915 # and https://youtrack.jetbrains.com/issue/PY-51428 DeprecationWarning = PydanticDeprecatedSince20 __all__ = 'Field', 'PrivateAttr', 'computed_field' _Unset: Any = PydanticUndefined if sys.version_info >= (3, 13): import warnings Deprecated: TypeAlias = warnings.deprecated | deprecated else: Deprecated: TypeAlias = deprecated class _FromFieldInfoInputs(typing_extensions.TypedDict, total=False): """This class exists solely to add type checking for the `**kwargs` in `FieldInfo.from_field`.""" annotation: type[Any] | None default_factory: typing.Callable[[], Any] | None alias: str | None alias_priority: int | None validation_alias: str | AliasPath | AliasChoices | None serialization_alias: str | None title: str | None field_title_generator: typing_extensions.Callable[[str, FieldInfo], str] | None description: str | None examples: list[Any] | None exclude: bool | None gt: annotated_types.SupportsGt | None ge: annotated_types.SupportsGe | None lt: annotated_types.SupportsLt | None le: annotated_types.SupportsLe | None multiple_of: float | None strict: bool | None min_length: int | None max_length: int | None pattern: str | typing.Pattern[str] | None allow_inf_nan: bool | None max_digits: int | None decimal_places: int | None union_mode: Literal['smart', 'left_to_right'] | None discriminator: str | types.Discriminator | None deprecated: Deprecated | str | bool | None json_schema_extra: JsonDict | typing.Callable[[JsonDict], None] | None frozen: bool | None validate_default: bool | None repr: bool init: bool | None init_var: bool | None kw_only: bool | None coerce_numbers_to_str: bool | None fail_fast: bool | None class _FieldInfoInputs(_FromFieldInfoInputs, total=False): """This class exists solely to add type checking for the `**kwargs` in `FieldInfo.__init__`.""" default: Any class FieldInfo(_repr.Representation): """This class holds information about a field. `FieldInfo` is used for any field definition regardless of whether the [`Field()`][pydantic.fields.Field] function is explicitly used. !!! warning You generally shouldn't be creating `FieldInfo` directly, you'll only need to use it when accessing [`BaseModel`][pydantic.main.BaseModel] `.model_fields` internals. Attributes: annotation: The type annotation of the field. default: The default value of the field. default_factory: The factory function used to construct the default for the field. alias: The alias name of the field. alias_priority: The priority of the field's alias. validation_alias: The validation alias of the field. serialization_alias: The serialization alias of the field. title: The title of the field. field_title_generator: A callable that takes a field name and returns title for it. description: The description of the field. examples: List of examples of the field. exclude: Whether to exclude the field from the model serialization. discriminator: Field name or Discriminator for discriminating the type in a tagged union. deprecated: A deprecation message, an instance of `warnings.deprecated` or the `typing_extensions.deprecated` backport, or a boolean. If `True`, a default deprecation message will be emitted when accessing the field. json_schema_extra: A dict or callable to provide extra JSON schema properties. frozen: Whether the field is frozen. validate_default: Whether to validate the default value of the field. repr: Whether to include the field in representation of the model. init: Whether the field should be included in the constructor of the dataclass. init_var: Whether the field should _only_ be included in the constructor of the dataclass, and not stored. kw_only: Whether the field should be a keyword-only argument in the constructor of the dataclass. metadata: List of metadata constraints. """ annotation: type[Any] | None default: Any default_factory: typing.Callable[[], Any] | None alias: str | None alias_priority: int | None validation_alias: str | AliasPath | AliasChoices | None serialization_alias: str | None title: str | None field_title_generator: typing.Callable[[str, FieldInfo], str] | None description: str | None examples: list[Any] | None exclude: bool | None discriminator: str | types.Discriminator | None deprecated: Deprecated | str | bool | None json_schema_extra: JsonDict | typing.Callable[[JsonDict], None] | None frozen: bool | None validate_default: bool | None repr: bool init: bool | None init_var: bool | None kw_only: bool | None metadata: list[Any] __slots__ = ( 'annotation', 'default', 'default_factory', 'alias', 'alias_priority', 'validation_alias', 'serialization_alias', 'title', 'field_title_generator', 'description', 'examples', 'exclude', 'discriminator', 'deprecated', 'json_schema_extra', 'frozen', 'validate_default', 'repr', 'init', 'init_var', 'kw_only', 'metadata', '_attributes_set', ) # used to convert kwargs to metadata/constraints, # None has a special meaning - these items are collected into a `PydanticGeneralMetadata` metadata_lookup: ClassVar[dict[str, typing.Callable[[Any], Any] | None]] = { 'strict': types.Strict, 'gt': annotated_types.Gt, 'ge': annotated_types.Ge, 'lt': annotated_types.Lt, 'le': annotated_types.Le, 'multiple_of': annotated_types.MultipleOf, 'min_length': annotated_types.MinLen, 'max_length': annotated_types.MaxLen, 'pattern': None, 'allow_inf_nan': None, 'max_digits': None, 'decimal_places': None, 'union_mode': None, 'coerce_numbers_to_str': None, 'fail_fast': types.FailFast, } def __init__(self, **kwargs: Unpack[_FieldInfoInputs]) -> None: """This class should generally not be initialized directly; instead, use the `pydantic.fields.Field` function or one of the constructor classmethods. See the signature of `pydantic.fields.Field` for more details about the expected arguments. """ self._attributes_set = {k: v for k, v in kwargs.items() if v is not _Unset} kwargs = {k: _DefaultValues.get(k) if v is _Unset else v for k, v in kwargs.items()} # type: ignore self.annotation, annotation_metadata = self._extract_metadata(kwargs.get('annotation')) default = kwargs.pop('default', PydanticUndefined) if default is Ellipsis: self.default = PydanticUndefined else: self.default = default self.default_factory = kwargs.pop('default_factory', None) if self.default is not PydanticUndefined and self.default_factory is not None: raise TypeError('cannot specify both default and default_factory') self.alias = kwargs.pop('alias', None) self.validation_alias = kwargs.pop('validation_alias', None) self.serialization_alias = kwargs.pop('serialization_alias', None) alias_is_set = any(alias is not None for alias in (self.alias, self.validation_alias, self.serialization_alias)) self.alias_priority = kwargs.pop('alias_priority', None) or 2 if alias_is_set else None self.title = kwargs.pop('title', None) self.field_title_generator = kwargs.pop('field_title_generator', None) self.description = kwargs.pop('description', None) self.examples = kwargs.pop('examples', None) self.exclude = kwargs.pop('exclude', None) self.discriminator = kwargs.pop('discriminator', None) # For compatibility with FastAPI<=0.110.0, we preserve the existing value if it is not overridden self.deprecated = kwargs.pop('deprecated', getattr(self, 'deprecated', None)) self.repr = kwargs.pop('repr', True) self.json_schema_extra = kwargs.pop('json_schema_extra', None) self.validate_default = kwargs.pop('validate_default', None) self.frozen = kwargs.pop('frozen', None) # currently only used on dataclasses self.init = kwargs.pop('init', None) self.init_var = kwargs.pop('init_var', None) self.kw_only = kwargs.pop('kw_only', None) self.metadata = self._collect_metadata(kwargs) + annotation_metadata # type: ignore @staticmethod def from_field(default: Any = PydanticUndefined, **kwargs: Unpack[_FromFieldInfoInputs]) -> FieldInfo: """Create a new `FieldInfo` object with the `Field` function. Args: default: The default value for the field. Defaults to Undefined. **kwargs: Additional arguments dictionary. Raises: TypeError: If 'annotation' is passed as a keyword argument. Returns: A new FieldInfo object with the given parameters. Example: This is how you can create a field with default value like this: ```python import pydantic class MyModel(pydantic.BaseModel): foo: int = pydantic.Field(4) ``` """ if 'annotation' in kwargs: raise TypeError('"annotation" is not permitted as a Field keyword argument') return FieldInfo(default=default, **kwargs) @staticmethod def from_annotation(annotation: type[Any]) -> FieldInfo: """Creates a `FieldInfo` instance from a bare annotation. This function is used internally to create a `FieldInfo` from a bare annotation like this: ```python import pydantic class MyModel(pydantic.BaseModel): foo: int # <-- like this ``` We also account for the case where the annotation can be an instance of `Annotated` and where one of the (not first) arguments in `Annotated` is an instance of `FieldInfo`, e.g.: ```python import annotated_types from typing_extensions import Annotated import pydantic class MyModel(pydantic.BaseModel): foo: Annotated[int, annotated_types.Gt(42)] bar: Annotated[int, pydantic.Field(gt=42)] ``` Args: annotation: An annotation object. Returns: An instance of the field metadata. """ final = False if _typing_extra.is_finalvar(annotation): final = True if annotation is not typing_extensions.Final: annotation = typing_extensions.get_args(annotation)[0] if _typing_extra.is_annotated(annotation): first_arg, *extra_args = typing_extensions.get_args(annotation) if _typing_extra.is_finalvar(first_arg): final = True field_info_annotations = [a for a in extra_args if isinstance(a, FieldInfo)] field_info = FieldInfo.merge_field_infos(*field_info_annotations, annotation=first_arg) if field_info: new_field_info = copy(field_info) new_field_info.annotation = first_arg new_field_info.frozen = final or field_info.frozen metadata: list[Any] = [] for a in extra_args: if _typing_extra.is_deprecated_instance(a): new_field_info.deprecated = a.message elif not isinstance(a, FieldInfo): metadata.append(a) else: metadata.extend(a.metadata) new_field_info.metadata = metadata return new_field_info return FieldInfo(annotation=annotation, frozen=final or None) # pyright: ignore[reportArgumentType] @staticmethod def from_annotated_attribute(annotation: type[Any], default: Any) -> FieldInfo: """Create `FieldInfo` from an annotation with a default value. This is used in cases like the following: ```python import annotated_types from typing_extensions import Annotated import pydantic class MyModel(pydantic.BaseModel): foo: int = 4 # <-- like this bar: Annotated[int, annotated_types.Gt(4)] = 4 # <-- or this spam: Annotated[int, pydantic.Field(gt=4)] = 4 # <-- or this ``` Args: annotation: The type annotation of the field. default: The default value of the field. Returns: A field object with the passed values. """ if annotation is default: raise PydanticUserError( 'Error when building FieldInfo from annotated attribute. ' "Make sure you don't have any field name clashing with a type annotation ", code='unevaluable-type-annotation', ) final = False if _typing_extra.is_finalvar(annotation): final = True if annotation is not typing_extensions.Final: annotation = typing_extensions.get_args(annotation)[0] if isinstance(default, FieldInfo): default.annotation, annotation_metadata = FieldInfo._extract_metadata(annotation) # pyright: ignore[reportArgumentType] default.metadata += annotation_metadata default = default.merge_field_infos( *[x for x in annotation_metadata if isinstance(x, FieldInfo)], default, annotation=default.annotation ) default.frozen = final or default.frozen return default elif isinstance(default, dataclasses.Field): init_var = False if annotation is dataclasses.InitVar: init_var = True annotation = typing.cast(Any, Any) elif isinstance(annotation, dataclasses.InitVar): init_var = True annotation = annotation.type pydantic_field = FieldInfo._from_dataclass_field(default) pydantic_field.annotation, annotation_metadata = FieldInfo._extract_metadata(annotation) # pyright: ignore[reportArgumentType] pydantic_field.metadata += annotation_metadata pydantic_field = pydantic_field.merge_field_infos( *[x for x in annotation_metadata if isinstance(x, FieldInfo)], pydantic_field, annotation=pydantic_field.annotation, ) pydantic_field.frozen = final or pydantic_field.frozen pydantic_field.init_var = init_var pydantic_field.init = getattr(default, 'init', None) pydantic_field.kw_only = getattr(default, 'kw_only', None) return pydantic_field else: if _typing_extra.is_annotated(annotation): first_arg, *extra_args = typing_extensions.get_args(annotation) field_infos = [a for a in extra_args if isinstance(a, FieldInfo)] field_info = FieldInfo.merge_field_infos(*field_infos, annotation=first_arg, default=default) metadata: list[Any] = [] for a in extra_args: if _typing_extra.is_deprecated_instance(a): field_info.deprecated = a.message elif not isinstance(a, FieldInfo): metadata.append(a) else: metadata.extend(a.metadata) field_info.metadata = metadata return field_info return FieldInfo(annotation=annotation, default=default, frozen=final or None) # pyright: ignore[reportArgumentType] @staticmethod def merge_field_infos(*field_infos: FieldInfo, **overrides: Any) -> FieldInfo: """Merge `FieldInfo` instances keeping only explicitly set attributes. Later `FieldInfo` instances override earlier ones. Returns: FieldInfo: A merged FieldInfo instance. """ flattened_field_infos: list[FieldInfo] = [] for field_info in field_infos: flattened_field_infos.extend(x for x in field_info.metadata if isinstance(x, FieldInfo)) flattened_field_infos.append(field_info) field_infos = tuple(flattened_field_infos) if len(field_infos) == 1: # No merging necessary, but we still need to make a copy and apply the overrides field_info = copy(field_infos[0]) field_info._attributes_set.update(overrides) default_override = overrides.pop('default', PydanticUndefined) if default_override is Ellipsis: default_override = PydanticUndefined if default_override is not PydanticUndefined: field_info.default = default_override for k, v in overrides.items(): setattr(field_info, k, v) return field_info # type: ignore new_kwargs: dict[str, Any] = {} metadata = {} for field_info in field_infos: new_kwargs.update(field_info._attributes_set) for x in field_info.metadata: if not isinstance(x, FieldInfo): metadata[type(x)] = x new_kwargs.update(overrides) field_info = FieldInfo(**new_kwargs) field_info.metadata = list(metadata.values()) return field_info @staticmethod def _from_dataclass_field(dc_field: DataclassField[Any]) -> FieldInfo: """Return a new `FieldInfo` instance from a `dataclasses.Field` instance. Args: dc_field: The `dataclasses.Field` instance to convert. Returns: The corresponding `FieldInfo` instance. Raises: TypeError: If any of the `FieldInfo` kwargs does not match the `dataclass.Field` kwargs. """ default = dc_field.default if default is dataclasses.MISSING: default = PydanticUndefined if dc_field.default_factory is dataclasses.MISSING: default_factory: typing.Callable[[], Any] | None = None else: default_factory = dc_field.default_factory # use the `Field` function so in correct kwargs raise the correct `TypeError` dc_field_metadata = {k: v for k, v in dc_field.metadata.items() if k in _FIELD_ARG_NAMES} return Field(default=default, default_factory=default_factory, repr=dc_field.repr, **dc_field_metadata) @staticmethod def _extract_metadata(annotation: type[Any] | None) -> tuple[type[Any] | None, list[Any]]: """Tries to extract metadata/constraints from an annotation if it uses `Annotated`. Args: annotation: The type hint annotation for which metadata has to be extracted. Returns: A tuple containing the extracted metadata type and the list of extra arguments. """ if annotation is not None: if _typing_extra.is_annotated(annotation): first_arg, *extra_args = typing_extensions.get_args(annotation) return first_arg, list(extra_args) return annotation, [] @staticmethod def _collect_metadata(kwargs: dict[str, Any]) -> list[Any]: """Collect annotations from kwargs. Args: kwargs: Keyword arguments passed to the function. Returns: A list of metadata objects - a combination of `annotated_types.BaseMetadata` and `PydanticMetadata`. """ metadata: list[Any] = [] general_metadata = {} for key, value in list(kwargs.items()): try: marker = FieldInfo.metadata_lookup[key] except KeyError: continue del kwargs[key] if value is not None: if marker is None: general_metadata[key] = value else: metadata.append(marker(value)) if general_metadata: metadata.append(_fields.pydantic_general_metadata(**general_metadata)) return metadata @property def deprecation_message(self) -> str | None: """The deprecation message to be emitted, or `None` if not set.""" if self.deprecated is None: return None if isinstance(self.deprecated, bool): return 'deprecated' if self.deprecated else None return self.deprecated if isinstance(self.deprecated, str) else self.deprecated.message def get_default(self, *, call_default_factory: bool = False) -> Any: """Get the default value. We expose an option for whether to call the default_factory (if present), as calling it may result in side effects that we want to avoid. However, there are times when it really should be called (namely, when instantiating a model via `model_construct`). Args: call_default_factory: Whether to call the default_factory or not. Defaults to `False`. Returns: The default value, calling the default factory if requested or `None` if not set. """ if self.default_factory is None: return _utils.smart_deepcopy(self.default) elif call_default_factory: return self.default_factory() else: return None def is_required(self) -> bool: """Check if the field is required (i.e., does not have a default value or factory). Returns: `True` if the field is required, `False` otherwise. """ return self.default is PydanticUndefined and self.default_factory is None def rebuild_annotation(self) -> Any: """Attempts to rebuild the original annotation for use in function signatures. If metadata is present, it adds it to the original annotation using `Annotated`. Otherwise, it returns the original annotation as-is. Note that because the metadata has been flattened, the original annotation may not be reconstructed exactly as originally provided, e.g. if the original type had unrecognized annotations, or was annotated with a call to `pydantic.Field`. Returns: The rebuilt annotation. """ if not self.metadata: return self.annotation else: # Annotated arguments must be a tuple return typing_extensions.Annotated[(self.annotation, *self.metadata)] # type: ignore def apply_typevars_map(self, typevars_map: dict[Any, Any] | None, types_namespace: dict[str, Any] | None) -> None: """Apply a `typevars_map` to the annotation. This method is used when analyzing parametrized generic types to replace typevars with their concrete types. This method applies the `typevars_map` to the annotation in place. Args: typevars_map: A dictionary mapping type variables to their concrete types. types_namespace (dict | None): A dictionary containing related types to the annotated type. See Also: pydantic._internal._generics.replace_types is used for replacing the typevars with their concrete types. """ annotation = _typing_extra.eval_type_lenient(self.annotation, types_namespace) self.annotation = _generics.replace_types(annotation, typevars_map) def __repr_args__(self) -> ReprArgs: yield 'annotation', _repr.PlainRepr(_repr.display_as_type(self.annotation)) yield 'required', self.is_required() for s in self.__slots__: if s == '_attributes_set': continue if s == 'annotation': continue elif s == 'metadata' and not self.metadata: continue elif s == 'repr' and self.repr is True: continue if s == 'frozen' and self.frozen is False: continue if s == 'validation_alias' and self.validation_alias == self.alias: continue if s == 'serialization_alias' and self.serialization_alias == self.alias: continue if s == 'default' and self.default is not PydanticUndefined: yield 'default', self.default elif s == 'default_factory' and self.default_factory is not None: yield 'default_factory', _repr.PlainRepr(_repr.display_as_type(self.default_factory)) else: value = getattr(self, s) if value is not None and value is not PydanticUndefined: yield s, value class _EmptyKwargs(typing_extensions.TypedDict): """This class exists solely to ensure that type checking warns about passing `**extra` in `Field`.""" _DefaultValues = dict( default=..., default_factory=None, alias=None, alias_priority=None, validation_alias=None, serialization_alias=None, title=None, description=None, examples=None, exclude=None, discriminator=None, json_schema_extra=None, frozen=None, validate_default=None, repr=True, init=None, init_var=None, kw_only=None, pattern=None, strict=None, gt=None, ge=None, lt=None, le=None, multiple_of=None, allow_inf_nan=None, max_digits=None, decimal_places=None, min_length=None, max_length=None, coerce_numbers_to_str=None, ) def Field( # noqa: C901 default: Any = PydanticUndefined, *, default_factory: typing.Callable[[], Any] | None = _Unset, alias: str | None = _Unset, alias_priority: int | None = _Unset, validation_alias: str | AliasPath | AliasChoices | None = _Unset, serialization_alias: str | None = _Unset, title: str | None = _Unset, field_title_generator: typing_extensions.Callable[[str, FieldInfo], str] | None = _Unset, description: str | None = _Unset, examples: list[Any] | None = _Unset, exclude: bool | None = _Unset, discriminator: str | types.Discriminator | None = _Unset, deprecated: Deprecated | str | bool | None = _Unset, json_schema_extra: JsonDict | typing.Callable[[JsonDict], None] | None = _Unset, frozen: bool | None = _Unset, validate_default: bool | None = _Unset, repr: bool = _Unset, init: bool | None = _Unset, init_var: bool | None = _Unset, kw_only: bool | None = _Unset, pattern: str | typing.Pattern[str] | None = _Unset, strict: bool | None = _Unset, coerce_numbers_to_str: bool | None = _Unset, gt: annotated_types.SupportsGt | None = _Unset, ge: annotated_types.SupportsGe | None = _Unset, lt: annotated_types.SupportsLt | None = _Unset, le: annotated_types.SupportsLe | None = _Unset, multiple_of: float | None = _Unset, allow_inf_nan: bool | None = _Unset, max_digits: int | None = _Unset, decimal_places: int | None = _Unset, min_length: int | None = _Unset, max_length: int | None = _Unset, union_mode: Literal['smart', 'left_to_right'] = _Unset, fail_fast: bool | None = _Unset, **extra: Unpack[_EmptyKwargs], ) -> Any: """Usage docs: https://docs.pydantic.dev/2.8/concepts/fields Create a field for objects that can be configured. Used to provide extra information about a field, either for the model schema or complex validation. Some arguments apply only to number fields (`int`, `float`, `Decimal`) and some apply only to `str`. Note: - Any `_Unset` objects will be replaced by the corresponding value defined in the `_DefaultValues` dictionary. If a key for the `_Unset` object is not found in the `_DefaultValues` dictionary, it will default to `None` Args: default: Default value if the field is not set. default_factory: A callable to generate the default value, such as :func:`~datetime.utcnow`. alias: The name to use for the attribute when validating or serializing by alias. This is often used for things like converting between snake and camel case. alias_priority: Priority of the alias. This affects whether an alias generator is used. validation_alias: Like `alias`, but only affects validation, not serialization. serialization_alias: Like `alias`, but only affects serialization, not validation. title: Human-readable title. field_title_generator: A callable that takes a field name and returns title for it. description: Human-readable description. examples: Example values for this field. exclude: Whether to exclude the field from the model serialization. discriminator: Field name or Discriminator for discriminating the type in a tagged union. deprecated: A deprecation message, an instance of `warnings.deprecated` or the `typing_extensions.deprecated` backport, or a boolean. If `True`, a default deprecation message will be emitted when accessing the field. json_schema_extra: A dict or callable to provide extra JSON schema properties. frozen: Whether the field is frozen. If true, attempts to change the value on an instance will raise an error. validate_default: If `True`, apply validation to the default value every time you create an instance. Otherwise, for performance reasons, the default value of the field is trusted and not validated. repr: A boolean indicating whether to include the field in the `__repr__` output. init: Whether the field should be included in the constructor of the dataclass. (Only applies to dataclasses.) init_var: Whether the field should _only_ be included in the constructor of the dataclass. (Only applies to dataclasses.) kw_only: Whether the field should be a keyword-only argument in the constructor of the dataclass. (Only applies to dataclasses.) coerce_numbers_to_str: Whether to enable coercion of any `Number` type to `str` (not applicable in `strict` mode). strict: If `True`, strict validation is applied to the field. See [Strict Mode](../concepts/strict_mode.md) for details. gt: Greater than. If set, value must be greater than this. Only applicable to numbers. ge: Greater than or equal. If set, value must be greater than or equal to this. Only applicable to numbers. lt: Less than. If set, value must be less than this. Only applicable to numbers. le: Less than or equal. If set, value must be less than or equal to this. Only applicable to numbers. multiple_of: Value must be a multiple of this. Only applicable to numbers. min_length: Minimum length for iterables. max_length: Maximum length for iterables. pattern: Pattern for strings (a regular expression). allow_inf_nan: Allow `inf`, `-inf`, `nan`. Only applicable to numbers. max_digits: Maximum number of allow digits for strings. decimal_places: Maximum number of decimal places allowed for numbers. union_mode: The strategy to apply when validating a union. Can be `smart` (the default), or `left_to_right`. See [Union Mode](../concepts/unions.md#union-modes) for details. fail_fast: If `True`, validation will stop on the first error. If `False`, all validation errors will be collected. This option can be applied only to iterable types (list, tuple, set, and frozenset). extra: (Deprecated) Extra fields that will be included in the JSON schema. !!! warning Deprecated The `extra` kwargs is deprecated. Use `json_schema_extra` instead. Returns: A new [`FieldInfo`][pydantic.fields.FieldInfo]. The return annotation is `Any` so `Field` can be used on type-annotated fields without causing a type error. """ # Check deprecated and removed params from V1. This logic should eventually be removed. const = extra.pop('const', None) # type: ignore if const is not None: raise PydanticUserError('`const` is removed, use `Literal` instead', code='removed-kwargs') min_items = extra.pop('min_items', None) # type: ignore if min_items is not None: warn('`min_items` is deprecated and will be removed, use `min_length` instead', DeprecationWarning) if min_length in (None, _Unset): min_length = min_items # type: ignore max_items = extra.pop('max_items', None) # type: ignore if max_items is not None: warn('`max_items` is deprecated and will be removed, use `max_length` instead', DeprecationWarning) if max_length in (None, _Unset): max_length = max_items # type: ignore unique_items = extra.pop('unique_items', None) # type: ignore if unique_items is not None: raise PydanticUserError( ( '`unique_items` is removed, use `Set` instead' '(this feature is discussed in https://github.com/pydantic/pydantic-core/issues/296)' ), code='removed-kwargs', ) allow_mutation = extra.pop('allow_mutation', None) # type: ignore if allow_mutation is not None: warn('`allow_mutation` is deprecated and will be removed. use `frozen` instead', DeprecationWarning) if allow_mutation is False: frozen = True regex = extra.pop('regex', None) # type: ignore if regex is not None: raise PydanticUserError('`regex` is removed. use `pattern` instead', code='removed-kwargs') if extra: warn( 'Using extra keyword arguments on `Field` is deprecated and will be removed.' ' Use `json_schema_extra` instead.' f' (Extra keys: {", ".join(k.__repr__() for k in extra.keys())})', DeprecationWarning, ) if not json_schema_extra or json_schema_extra is _Unset: json_schema_extra = extra # type: ignore if ( validation_alias and validation_alias is not _Unset and not isinstance(validation_alias, (str, AliasChoices, AliasPath)) ): raise TypeError('Invalid `validation_alias` type. it should be `str`, `AliasChoices`, or `AliasPath`') if serialization_alias in (_Unset, None) and isinstance(alias, str): serialization_alias = alias if validation_alias in (_Unset, None): validation_alias = alias include = extra.pop('include', None) # type: ignore if include is not None: warn('`include` is deprecated and does nothing. It will be removed, use `exclude` instead', DeprecationWarning) return FieldInfo.from_field( default, default_factory=default_factory, alias=alias, alias_priority=alias_priority, validation_alias=validation_alias, serialization_alias=serialization_alias, title=title, field_title_generator=field_title_generator, description=description, examples=examples, exclude=exclude, discriminator=discriminator, deprecated=deprecated, json_schema_extra=json_schema_extra, frozen=frozen, pattern=pattern, validate_default=validate_default, repr=repr, init=init, init_var=init_var, kw_only=kw_only, coerce_numbers_to_str=coerce_numbers_to_str, strict=strict, gt=gt, ge=ge, lt=lt, le=le, multiple_of=multiple_of, min_length=min_length, max_length=max_length, allow_inf_nan=allow_inf_nan, max_digits=max_digits, decimal_places=decimal_places, union_mode=union_mode, fail_fast=fail_fast, ) _FIELD_ARG_NAMES = set(inspect.signature(Field).parameters) _FIELD_ARG_NAMES.remove('extra') # do not include the varkwargs parameter class ModelPrivateAttr(_repr.Representation): """A descriptor for private attributes in class models. !!! warning You generally shouldn't be creating `ModelPrivateAttr` instances directly, instead use `pydantic.fields.PrivateAttr`. (This is similar to `FieldInfo` vs. `Field`.) Attributes: default: The default value of the attribute if not provided. default_factory: A callable function that generates the default value of the attribute if not provided. """ __slots__ = 'default', 'default_factory' def __init__( self, default: Any = PydanticUndefined, *, default_factory: typing.Callable[[], Any] | None = None ) -> None: self.default = default self.default_factory = default_factory if not typing.TYPE_CHECKING: # We put `__getattr__` in a non-TYPE_CHECKING block because otherwise, mypy allows arbitrary attribute access def __getattr__(self, item: str) -> Any: """This function improves compatibility with custom descriptors by ensuring delegation happens as expected when the default value of a private attribute is a descriptor. """ if item in {'__get__', '__set__', '__delete__'}: if hasattr(self.default, item): return getattr(self.default, item) raise AttributeError(f'{type(self).__name__!r} object has no attribute {item!r}') def __set_name__(self, cls: type[Any], name: str) -> None: """Preserve `__set_name__` protocol defined in https://peps.python.org/pep-0487.""" if self.default is PydanticUndefined: return if not hasattr(self.default, '__set_name__'): return set_name = self.default.__set_name__ if callable(set_name): set_name(cls, name) def get_default(self) -> Any: """Retrieve the default value of the object. If `self.default_factory` is `None`, the method will return a deep copy of the `self.default` object. If `self.default_factory` is not `None`, it will call `self.default_factory` and return the value returned. Returns: The default value of the object. """ return _utils.smart_deepcopy(self.default) if self.default_factory is None else self.default_factory() def __eq__(self, other: Any) -> bool: return isinstance(other, self.__class__) and (self.default, self.default_factory) == ( other.default, other.default_factory, ) def PrivateAttr( default: Any = PydanticUndefined, *, default_factory: typing.Callable[[], Any] | None = None, init: Literal[False] = False, ) -> Any: """Usage docs: https://docs.pydantic.dev/2.8/concepts/models/#private-model-attributes Indicates that an attribute is intended for private use and not handled during normal validation/serialization. Private attributes are not validated by Pydantic, so it's up to you to ensure they are used in a type-safe manner. Private attributes are stored in `__private_attributes__` on the model. Args: default: The attribute's default value. Defaults to Undefined. default_factory: Callable that will be called when a default value is needed for this attribute. If both `default` and `default_factory` are set, an error will be raised. init: Whether the attribute should be included in the constructor of the dataclass. Always `False`. Returns: An instance of [`ModelPrivateAttr`][pydantic.fields.ModelPrivateAttr] class. Raises: ValueError: If both `default` and `default_factory` are set. """ if default is not PydanticUndefined and default_factory is not None: raise TypeError('cannot specify both default and default_factory') return ModelPrivateAttr( default, default_factory=default_factory, ) @dataclasses.dataclass(**_internal_dataclass.slots_true) class ComputedFieldInfo: """A container for data from `@computed_field` so that we can access it while building the pydantic-core schema. Attributes: decorator_repr: A class variable representing the decorator string, '@computed_field'. wrapped_property: The wrapped computed field property. return_type: The type of the computed field property's return value. alias: The alias of the property to be used during serialization. alias_priority: The priority of the alias. This affects whether an alias generator is used. title: Title of the computed field to include in the serialization JSON schema. field_title_generator: A callable that takes a field name and returns title for it. description: Description of the computed field to include in the serialization JSON schema. deprecated: A deprecation message, an instance of `warnings.deprecated` or the `typing_extensions.deprecated` backport, or a boolean. If `True`, a default deprecation message will be emitted when accessing the field. examples: Example values of the computed field to include in the serialization JSON schema. json_schema_extra: A dict or callable to provide extra JSON schema properties. repr: A boolean indicating whether to include the field in the __repr__ output. """ decorator_repr: ClassVar[str] = '@computed_field' wrapped_property: property return_type: Any alias: str | None alias_priority: int | None title: str | None field_title_generator: typing.Callable[[str, ComputedFieldInfo], str] | None description: str | None deprecated: Deprecated | str | bool | None examples: list[Any] | None json_schema_extra: JsonDict | typing.Callable[[JsonDict], None] | None repr: bool @property def deprecation_message(self) -> str | None: """The deprecation message to be emitted, or `None` if not set.""" if self.deprecated is None: return None if isinstance(self.deprecated, bool): return 'deprecated' if self.deprecated else None return self.deprecated if isinstance(self.deprecated, str) else self.deprecated.message def _wrapped_property_is_private(property_: cached_property | property) -> bool: # type: ignore """Returns true if provided property is private, False otherwise.""" wrapped_name: str = '' if isinstance(property_, property): wrapped_name = getattr(property_.fget, '__name__', '') elif isinstance(property_, cached_property): # type: ignore wrapped_name = getattr(property_.func, '__name__', '') # type: ignore return wrapped_name.startswith('_') and not wrapped_name.startswith('__') # this should really be `property[T], cached_property[T]` but property is not generic unlike cached_property # See https://github.com/python/typing/issues/985 and linked issues PropertyT = typing.TypeVar('PropertyT') @typing.overload def computed_field( *, alias: str | None = None, alias_priority: int | None = None, title: str | None = None, field_title_generator: typing.Callable[[str, ComputedFieldInfo], str] | None = None, description: str | None = None, deprecated: Deprecated | str | bool | None = None, examples: list[Any] | None = None, json_schema_extra: JsonDict | typing.Callable[[JsonDict], None] | None = None, repr: bool = True, return_type: Any = PydanticUndefined, ) -> typing.Callable[[PropertyT], PropertyT]: ... @typing.overload def computed_field(__func: PropertyT) -> PropertyT: ... def computed_field( func: PropertyT | None = None, /, *, alias: str | None = None, alias_priority: int | None = None, title: str | None = None, field_title_generator: typing.Callable[[str, ComputedFieldInfo], str] | None = None, description: str | None = None, deprecated: Deprecated | str | bool | None = None, examples: list[Any] | None = None, json_schema_extra: JsonDict | typing.Callable[[JsonDict], None] | None = None, repr: bool | None = None, return_type: Any = PydanticUndefined, ) -> PropertyT | typing.Callable[[PropertyT], PropertyT]: """Usage docs: https://docs.pydantic.dev/2.8/concepts/fields#the-computed_field-decorator Decorator to include `property` and `cached_property` when serializing models or dataclasses. This is useful for fields that are computed from other fields, or for fields that are expensive to compute and should be cached. ```py from pydantic import BaseModel, computed_field class Rectangle(BaseModel): width: int length: int @computed_field @property def area(self) -> int: return self.width * self.length print(Rectangle(width=3, length=2).model_dump()) #> {'width': 3, 'length': 2, 'area': 6} ``` If applied to functions not yet decorated with `@property` or `@cached_property`, the function is automatically wrapped with `property`. Although this is more concise, you will lose IntelliSense in your IDE, and confuse static type checkers, thus explicit use of `@property` is recommended. !!! warning "Mypy Warning" Even with the `@property` or `@cached_property` applied to your function before `@computed_field`, mypy may throw a `Decorated property not supported` error. See [mypy issue #1362](https://github.com/python/mypy/issues/1362), for more information. To avoid this error message, add `# type: ignore[misc]` to the `@computed_field` line. [pyright](https://github.com/microsoft/pyright) supports `@computed_field` without error. ```py import random from pydantic import BaseModel, computed_field class Square(BaseModel): width: float @computed_field def area(self) -> float: # converted to a `property` by `computed_field` return round(self.width**2, 2) @area.setter def area(self, new_area: float) -> None: self.width = new_area**0.5 @computed_field(alias='the magic number', repr=False) def random_number(self) -> int: return random.randint(0, 1_000) square = Square(width=1.3) # `random_number` does not appear in representation print(repr(square)) #> Square(width=1.3, area=1.69) print(square.random_number) #> 3 square.area = 4 print(square.model_dump_json(by_alias=True)) #> {"width":2.0,"area":4.0,"the magic number":3} ``` !!! warning "Overriding with `computed_field`" You can't override a field from a parent class with a `computed_field` in the child class. `mypy` complains about this behavior if allowed, and `dataclasses` doesn't allow this pattern either. See the example below: ```py from pydantic import BaseModel, computed_field class Parent(BaseModel): a: str try: class Child(Parent): @computed_field @property def a(self) -> str: return 'new a' except ValueError as e: print(repr(e)) #> ValueError("you can't override a field with a computed field") ``` Private properties decorated with `@computed_field` have `repr=False` by default. ```py from functools import cached_property from pydantic import BaseModel, computed_field class Model(BaseModel): foo: int @computed_field @cached_property def _private_cached_property(self) -> int: return -self.foo @computed_field @property def _private_property(self) -> int: return -self.foo m = Model(foo=1) print(repr(m)) #> M(foo=1) ``` Args: func: the function to wrap. alias: alias to use when serializing this computed field, only used when `by_alias=True` alias_priority: priority of the alias. This affects whether an alias generator is used title: Title to use when including this computed field in JSON Schema field_title_generator: A callable that takes a field name and returns title for it. description: Description to use when including this computed field in JSON Schema, defaults to the function's docstring deprecated: A deprecation message (or an instance of `warnings.deprecated` or the `typing_extensions.deprecated` backport). to be emitted when accessing the field. Or a boolean. This will automatically be set if the property is decorated with the `deprecated` decorator. examples: Example values to use when including this computed field in JSON Schema json_schema_extra: A dict or callable to provide extra JSON schema properties. repr: whether to include this computed field in model repr. Default is `False` for private properties and `True` for public properties. return_type: optional return for serialization logic to expect when serializing to JSON, if included this must be correct, otherwise a `TypeError` is raised. If you don't include a return type Any is used, which does runtime introspection to handle arbitrary objects. Returns: A proxy wrapper for the property. """ def dec(f: Any) -> Any: nonlocal description, deprecated, return_type, alias_priority unwrapped = _decorators.unwrap_wrapped_function(f) if description is None and unwrapped.__doc__: description = inspect.cleandoc(unwrapped.__doc__) if deprecated is None and hasattr(unwrapped, '__deprecated__'): deprecated = unwrapped.__deprecated__ # if the function isn't already decorated with `@property` (or another descriptor), then we wrap it now f = _decorators.ensure_property(f) alias_priority = (alias_priority or 2) if alias is not None else None if repr is None: repr_: bool = not _wrapped_property_is_private(property_=f) else: repr_ = repr dec_info = ComputedFieldInfo( f, return_type, alias, alias_priority, title, field_title_generator, description, deprecated, examples, json_schema_extra, repr_, ) return _decorators.PydanticDescriptorProxy(f, dec_info) if func is None: return dec else: return dec(func)
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