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- """Private logic related to fields (the `Field()` function and `FieldInfo` class), and arguments to `Annotated`."""
- from __future__ import annotations as _annotations
- import dataclasses
- import warnings
- from collections.abc import Mapping
- from copy import copy
- from functools import cache
- from inspect import Parameter, ismethoddescriptor, signature
- from re import Pattern
- from typing import TYPE_CHECKING, Any, Callable, TypeVar
- from pydantic_core import PydanticUndefined
- from typing_extensions import TypeIs
- from typing_inspection.introspection import AnnotationSource
- from pydantic import PydanticDeprecatedSince211
- from pydantic.errors import PydanticUserError
- from ..aliases import AliasGenerator
- from . import _generics, _typing_extra
- from ._config import ConfigWrapper
- from ._docs_extraction import extract_docstrings_from_cls
- from ._import_utils import import_cached_base_model, import_cached_field_info
- from ._namespace_utils import NsResolver
- from ._repr import Representation
- from ._utils import can_be_positional, get_first_not_none
- if TYPE_CHECKING:
- from annotated_types import BaseMetadata
- from ..fields import FieldInfo
- from ..main import BaseModel
- from ._dataclasses import PydanticDataclass, StandardDataclass
- from ._decorators import DecoratorInfos
- class PydanticMetadata(Representation):
- """Base class for annotation markers like `Strict`."""
- __slots__ = ()
- def pydantic_general_metadata(**metadata: Any) -> BaseMetadata:
- """Create a new `_PydanticGeneralMetadata` class with the given metadata.
- Args:
- **metadata: The metadata to add.
- Returns:
- The new `_PydanticGeneralMetadata` class.
- """
- return _general_metadata_cls()(metadata) # type: ignore
- @cache
- def _general_metadata_cls() -> type[BaseMetadata]:
- """Do it this way to avoid importing `annotated_types` at import time."""
- from annotated_types import BaseMetadata
- class _PydanticGeneralMetadata(PydanticMetadata, BaseMetadata):
- """Pydantic general metadata like `max_digits`."""
- def __init__(self, metadata: Any):
- self.__dict__ = metadata
- return _PydanticGeneralMetadata # type: ignore
- def _check_protected_namespaces(
- protected_namespaces: tuple[str | Pattern[str], ...],
- ann_name: str,
- bases: tuple[type[Any], ...],
- cls_name: str,
- ) -> None:
- BaseModel = import_cached_base_model()
- for protected_namespace in protected_namespaces:
- ns_violation = False
- if isinstance(protected_namespace, Pattern):
- ns_violation = protected_namespace.match(ann_name) is not None
- elif isinstance(protected_namespace, str):
- ns_violation = ann_name.startswith(protected_namespace)
- if ns_violation:
- for b in bases:
- if hasattr(b, ann_name):
- if not (issubclass(b, BaseModel) and ann_name in getattr(b, '__pydantic_fields__', {})):
- raise ValueError(
- f'Field {ann_name!r} conflicts with member {getattr(b, ann_name)}'
- f' of protected namespace {protected_namespace!r}.'
- )
- else:
- valid_namespaces: list[str] = []
- for pn in protected_namespaces:
- if isinstance(pn, Pattern):
- if not pn.match(ann_name):
- valid_namespaces.append(f're.compile({pn.pattern!r})')
- else:
- if not ann_name.startswith(pn):
- valid_namespaces.append(f"'{pn}'")
- valid_namespaces_str = f'({", ".join(valid_namespaces)}{",)" if len(valid_namespaces) == 1 else ")"}'
- warnings.warn(
- f'Field {ann_name!r} in {cls_name!r} conflicts with protected namespace {protected_namespace!r}.\n\n'
- f"You may be able to solve this by setting the 'protected_namespaces' configuration to {valid_namespaces_str}.",
- UserWarning,
- stacklevel=5,
- )
- def _update_fields_from_docstrings(cls: type[Any], fields: dict[str, FieldInfo], use_inspect: bool = False) -> None:
- fields_docs = extract_docstrings_from_cls(cls, use_inspect=use_inspect)
- for ann_name, field_info in fields.items():
- if field_info.description is None and ann_name in fields_docs:
- field_info.description = fields_docs[ann_name]
- def _apply_field_title_generator_to_field_info(
- title_generator: Callable[[str, FieldInfo], str],
- field_name: str,
- field_info: FieldInfo,
- ):
- if field_info.title is None:
- title = title_generator(field_name, field_info)
- if not isinstance(title, str):
- raise TypeError(f'field_title_generator {title_generator} must return str, not {title.__class__}')
- field_info.title = title
- def _apply_alias_generator_to_field_info(
- alias_generator: Callable[[str], str] | AliasGenerator, field_name: str, field_info: FieldInfo
- ):
- """Apply an alias generator to aliases on a `FieldInfo` instance if appropriate.
- Args:
- alias_generator: A callable that takes a string and returns a string, or an `AliasGenerator` instance.
- field_name: The name of the field from which to generate the alias.
- field_info: The `FieldInfo` instance to which the alias generator is (maybe) applied.
- """
- # Apply an alias_generator if
- # 1. An alias is not specified
- # 2. An alias is specified, but the priority is <= 1
- if (
- field_info.alias_priority is None
- or field_info.alias_priority <= 1
- or field_info.alias is None
- or field_info.validation_alias is None
- or field_info.serialization_alias is None
- ):
- alias, validation_alias, serialization_alias = None, None, None
- if isinstance(alias_generator, AliasGenerator):
- alias, validation_alias, serialization_alias = alias_generator.generate_aliases(field_name)
- elif callable(alias_generator):
- alias = alias_generator(field_name)
- if not isinstance(alias, str):
- raise TypeError(f'alias_generator {alias_generator} must return str, not {alias.__class__}')
- # if priority is not set, we set to 1
- # which supports the case where the alias_generator from a child class is used
- # to generate an alias for a field in a parent class
- if field_info.alias_priority is None or field_info.alias_priority <= 1:
- field_info.alias_priority = 1
- # if the priority is 1, then we set the aliases to the generated alias
- if field_info.alias_priority == 1:
- field_info.serialization_alias = get_first_not_none(serialization_alias, alias)
- field_info.validation_alias = get_first_not_none(validation_alias, alias)
- field_info.alias = alias
- # if any of the aliases are not set, then we set them to the corresponding generated alias
- if field_info.alias is None:
- field_info.alias = alias
- if field_info.serialization_alias is None:
- field_info.serialization_alias = get_first_not_none(serialization_alias, alias)
- if field_info.validation_alias is None:
- field_info.validation_alias = get_first_not_none(validation_alias, alias)
- def update_field_from_config(config_wrapper: ConfigWrapper, field_name: str, field_info: FieldInfo) -> None:
- """Update the `FieldInfo` instance from the configuration set on the model it belongs to.
- This will apply the title and alias generators from the configuration.
- Args:
- config_wrapper: The configuration from the model.
- field_name: The field name the `FieldInfo` instance is attached to.
- field_info: The `FieldInfo` instance to update.
- """
- field_title_generator = field_info.field_title_generator or config_wrapper.field_title_generator
- if field_title_generator is not None:
- _apply_field_title_generator_to_field_info(field_title_generator, field_name, field_info)
- if config_wrapper.alias_generator is not None:
- _apply_alias_generator_to_field_info(config_wrapper.alias_generator, field_name, field_info)
- _deprecated_method_names = {'dict', 'json', 'copy', '_iter', '_copy_and_set_values', '_calculate_keys'}
- _deprecated_classmethod_names = {
- 'parse_obj',
- 'parse_raw',
- 'parse_file',
- 'from_orm',
- 'construct',
- 'schema',
- 'schema_json',
- 'validate',
- 'update_forward_refs',
- '_get_value',
- }
- def collect_model_fields( # noqa: C901
- cls: type[BaseModel],
- config_wrapper: ConfigWrapper,
- ns_resolver: NsResolver | None,
- *,
- typevars_map: Mapping[TypeVar, Any] | None = None,
- ) -> tuple[dict[str, FieldInfo], set[str]]:
- """Collect the fields and class variables names of a nascent Pydantic model.
- The fields collection process is *lenient*, meaning it won't error if string annotations
- fail to evaluate. If this happens, the original annotation (and assigned value, if any)
- is stored on the created `FieldInfo` instance.
- The `rebuild_model_fields()` should be called at a later point (e.g. when rebuilding the model),
- and will make use of these stored attributes.
- Args:
- cls: BaseModel or dataclass.
- config_wrapper: The config wrapper instance.
- ns_resolver: Namespace resolver to use when getting model annotations.
- typevars_map: A dictionary mapping type variables to their concrete types.
- Returns:
- A two-tuple containing model fields and class variables names.
- Raises:
- NameError:
- - If there is a conflict between a field name and protected namespaces.
- - If there is a field other than `root` in `RootModel`.
- - If a field shadows an attribute in the parent model.
- """
- FieldInfo_ = import_cached_field_info()
- BaseModel_ = import_cached_base_model()
- bases = cls.__bases__
- parent_fields_lookup: dict[str, FieldInfo] = {}
- for base in reversed(bases):
- if model_fields := getattr(base, '__pydantic_fields__', None):
- parent_fields_lookup.update(model_fields)
- type_hints = _typing_extra.get_model_type_hints(cls, ns_resolver=ns_resolver)
- # https://docs.python.org/3/howto/annotations.html#accessing-the-annotations-dict-of-an-object-in-python-3-9-and-older
- # annotations is only used for finding fields in parent classes
- annotations = _typing_extra.safe_get_annotations(cls)
- fields: dict[str, FieldInfo] = {}
- class_vars: set[str] = set()
- for ann_name, (ann_type, evaluated) in type_hints.items():
- if ann_name == 'model_config':
- # We never want to treat `model_config` as a field
- # Note: we may need to change this logic if/when we introduce a `BareModel` class with no
- # protected namespaces (where `model_config` might be allowed as a field name)
- continue
- _check_protected_namespaces(
- protected_namespaces=config_wrapper.protected_namespaces,
- ann_name=ann_name,
- bases=bases,
- cls_name=cls.__name__,
- )
- if _typing_extra.is_classvar_annotation(ann_type):
- class_vars.add(ann_name)
- continue
- assigned_value = getattr(cls, ann_name, PydanticUndefined)
- if assigned_value is not PydanticUndefined and (
- # One of the deprecated instance methods was used as a field name (e.g. `dict()`):
- any(getattr(BaseModel_, depr_name, None) is assigned_value for depr_name in _deprecated_method_names)
- # One of the deprecated class methods was used as a field name (e.g. `schema()`):
- or (
- hasattr(assigned_value, '__func__')
- and any(
- getattr(getattr(BaseModel_, depr_name, None), '__func__', None) is assigned_value.__func__ # pyright: ignore[reportAttributeAccessIssue]
- for depr_name in _deprecated_classmethod_names
- )
- )
- ):
- # Then `assigned_value` would be the method, even though no default was specified:
- assigned_value = PydanticUndefined
- if not is_valid_field_name(ann_name):
- continue
- if cls.__pydantic_root_model__ and ann_name != 'root':
- raise NameError(
- f"Unexpected field with name {ann_name!r}; only 'root' is allowed as a field of a `RootModel`"
- )
- # when building a generic model with `MyModel[int]`, the generic_origin check makes sure we don't get
- # "... shadows an attribute" warnings
- generic_origin = getattr(cls, '__pydantic_generic_metadata__', {}).get('origin')
- for base in bases:
- dataclass_fields = {
- field.name for field in (dataclasses.fields(base) if dataclasses.is_dataclass(base) else ())
- }
- if hasattr(base, ann_name):
- if base is generic_origin:
- # Don't warn when "shadowing" of attributes in parametrized generics
- continue
- if ann_name in dataclass_fields:
- # Don't warn when inheriting stdlib dataclasses whose fields are "shadowed" by defaults being set
- # on the class instance.
- continue
- if ann_name not in annotations:
- # Don't warn when a field exists in a parent class but has not been defined in the current class
- continue
- warnings.warn(
- f'Field name "{ann_name}" in "{cls.__qualname__}" shadows an attribute in parent '
- f'"{base.__qualname__}"',
- UserWarning,
- stacklevel=4,
- )
- if assigned_value is PydanticUndefined: # no assignment, just a plain annotation
- if ann_name in annotations or ann_name not in parent_fields_lookup:
- # field is either:
- # - present in the current model's annotations (and *not* from parent classes)
- # - not found on any base classes; this seems to be caused by fields bot getting
- # generated due to models not being fully defined while initializing recursive models.
- # Nothing stops us from just creating a `FieldInfo` for this type hint, so we do this.
- field_info = FieldInfo_.from_annotation(ann_type, _source=AnnotationSource.CLASS)
- if not evaluated:
- field_info._complete = False
- # Store the original annotation that should be used to rebuild
- # the field info later:
- field_info._original_annotation = ann_type
- else:
- # The field was present on one of the (possibly multiple) base classes
- # copy the field to make sure typevar substitutions don't cause issues with the base classes
- field_info = copy(parent_fields_lookup[ann_name])
- else: # An assigned value is present (either the default value, or a `Field()` function)
- if isinstance(assigned_value, FieldInfo_) and ismethoddescriptor(assigned_value.default):
- # `assigned_value` was fetched using `getattr`, which triggers a call to `__get__`
- # for descriptors, so we do the same if the `= field(default=...)` form is used.
- # Note that we only do this for method descriptors for now, we might want to
- # extend this to any descriptor in the future (by simply checking for
- # `hasattr(assigned_value.default, '__get__')`).
- default = assigned_value.default.__get__(None, cls)
- assigned_value.default = default
- assigned_value._attributes_set['default'] = default
- field_info = FieldInfo_.from_annotated_attribute(ann_type, assigned_value, _source=AnnotationSource.CLASS)
- # Store the original annotation and assignment value that should be used to rebuild the field info later.
- # Note that the assignment is always stored as the annotation might contain a type var that is later
- # parameterized with an unknown forward reference (and we'll need it to rebuild the field info):
- field_info._original_assignment = assigned_value
- if not evaluated:
- field_info._complete = False
- field_info._original_annotation = ann_type
- elif 'final' in field_info._qualifiers and not field_info.is_required():
- warnings.warn(
- f'Annotation {ann_name!r} is marked as final and has a default value. Pydantic treats {ann_name!r} as a '
- 'class variable, but it will be considered as a normal field in V3 to be aligned with dataclasses. If you '
- f'still want {ann_name!r} to be considered as a class variable, annotate it as: `ClassVar[<type>] = <default>.`',
- category=PydanticDeprecatedSince211,
- # Incorrect when `create_model` is used, but the chance that final with a default is used is low in that case:
- stacklevel=4,
- )
- class_vars.add(ann_name)
- continue
- # attributes which are fields are removed from the class namespace:
- # 1. To match the behaviour of annotation-only fields
- # 2. To avoid false positives in the NameError check above
- try:
- delattr(cls, ann_name)
- except AttributeError:
- pass # indicates the attribute was on a parent class
- # Use cls.__dict__['__pydantic_decorators__'] instead of cls.__pydantic_decorators__
- # to make sure the decorators have already been built for this exact class
- decorators: DecoratorInfos = cls.__dict__['__pydantic_decorators__']
- if ann_name in decorators.computed_fields:
- raise TypeError(
- f'Field {ann_name!r} of class {cls.__name__!r} overrides symbol of same name in a parent class. '
- 'This override with a computed_field is incompatible.'
- )
- fields[ann_name] = field_info
- if field_info._complete:
- # If not complete, this will be called in `rebuild_model_fields()`:
- update_field_from_config(config_wrapper, ann_name, field_info)
- if typevars_map:
- for field in fields.values():
- if field._complete:
- field.apply_typevars_map(typevars_map)
- if config_wrapper.use_attribute_docstrings:
- _update_fields_from_docstrings(cls, fields)
- return fields, class_vars
- def rebuild_model_fields(
- cls: type[BaseModel],
- *,
- config_wrapper: ConfigWrapper,
- ns_resolver: NsResolver,
- typevars_map: Mapping[TypeVar, Any],
- ) -> dict[str, FieldInfo]:
- """Rebuild the (already present) model fields by trying to reevaluate annotations.
- This function should be called whenever a model with incomplete fields is encountered.
- Raises:
- NameError: If one of the annotations failed to evaluate.
- Note:
- This function *doesn't* mutate the model fields in place, as it can be called during
- schema generation, where you don't want to mutate other model's fields.
- """
- FieldInfo_ = import_cached_field_info()
- rebuilt_fields: dict[str, FieldInfo] = {}
- with ns_resolver.push(cls):
- for f_name, field_info in cls.__pydantic_fields__.items():
- if field_info._complete:
- rebuilt_fields[f_name] = field_info
- else:
- existing_desc = field_info.description
- ann = _typing_extra.eval_type(
- field_info._original_annotation,
- *ns_resolver.types_namespace,
- )
- ann = _generics.replace_types(ann, typevars_map)
- if (assign := field_info._original_assignment) is PydanticUndefined:
- new_field = FieldInfo_.from_annotation(ann, _source=AnnotationSource.CLASS)
- else:
- new_field = FieldInfo_.from_annotated_attribute(ann, assign, _source=AnnotationSource.CLASS)
- # The description might come from the docstring if `use_attribute_docstrings` was `True`:
- new_field.description = new_field.description if new_field.description is not None else existing_desc
- update_field_from_config(config_wrapper, f_name, new_field)
- rebuilt_fields[f_name] = new_field
- return rebuilt_fields
- def collect_dataclass_fields(
- cls: type[StandardDataclass],
- *,
- config_wrapper: ConfigWrapper,
- ns_resolver: NsResolver | None = None,
- typevars_map: dict[Any, Any] | None = None,
- ) -> dict[str, FieldInfo]:
- """Collect the fields of a dataclass.
- Args:
- cls: dataclass.
- config_wrapper: The config wrapper instance.
- ns_resolver: Namespace resolver to use when getting dataclass annotations.
- Defaults to an empty instance.
- typevars_map: A dictionary mapping type variables to their concrete types.
- Returns:
- The dataclass fields.
- """
- FieldInfo_ = import_cached_field_info()
- fields: dict[str, FieldInfo] = {}
- ns_resolver = ns_resolver or NsResolver()
- dataclass_fields = cls.__dataclass_fields__
- # The logic here is similar to `_typing_extra.get_cls_type_hints`,
- # although we do it manually as stdlib dataclasses already have annotations
- # collected in each class:
- for base in reversed(cls.__mro__):
- if not dataclasses.is_dataclass(base):
- continue
- with ns_resolver.push(base):
- for ann_name, dataclass_field in dataclass_fields.items():
- base_anns = _typing_extra.safe_get_annotations(base)
- if ann_name not in base_anns:
- # `__dataclass_fields__`contains every field, even the ones from base classes.
- # Only collect the ones defined on `base`.
- continue
- globalns, localns = ns_resolver.types_namespace
- ann_type, evaluated = _typing_extra.try_eval_type(dataclass_field.type, globalns, localns)
- if _typing_extra.is_classvar_annotation(ann_type):
- continue
- if (
- not dataclass_field.init
- and dataclass_field.default is dataclasses.MISSING
- and dataclass_field.default_factory is dataclasses.MISSING
- ):
- # TODO: We should probably do something with this so that validate_assignment behaves properly
- # Issue: https://github.com/pydantic/pydantic/issues/5470
- continue
- if isinstance(dataclass_field.default, FieldInfo_):
- if dataclass_field.default.init_var:
- if dataclass_field.default.init is False:
- raise PydanticUserError(
- f'Dataclass field {ann_name} has init=False and init_var=True, but these are mutually exclusive.',
- code='clashing-init-and-init-var',
- )
- # TODO: same note as above re validate_assignment
- continue
- field_info = FieldInfo_.from_annotated_attribute(
- ann_type, dataclass_field.default, _source=AnnotationSource.DATACLASS
- )
- field_info._original_assignment = dataclass_field.default
- else:
- field_info = FieldInfo_.from_annotated_attribute(
- ann_type, dataclass_field, _source=AnnotationSource.DATACLASS
- )
- field_info._original_assignment = dataclass_field
- if not evaluated:
- field_info._complete = False
- field_info._original_annotation = ann_type
- fields[ann_name] = field_info
- update_field_from_config(config_wrapper, ann_name, field_info)
- if field_info.default is not PydanticUndefined and isinstance(
- getattr(cls, ann_name, field_info), FieldInfo_
- ):
- # We need this to fix the default when the "default" from __dataclass_fields__ is a pydantic.FieldInfo
- setattr(cls, ann_name, field_info.default)
- if typevars_map:
- for field in fields.values():
- # We don't pass any ns, as `field.annotation`
- # was already evaluated. TODO: is this method relevant?
- # Can't we juste use `_generics.replace_types`?
- field.apply_typevars_map(typevars_map)
- if config_wrapper.use_attribute_docstrings:
- _update_fields_from_docstrings(
- cls,
- fields,
- # We can't rely on the (more reliable) frame inspection method
- # for stdlib dataclasses:
- use_inspect=not hasattr(cls, '__is_pydantic_dataclass__'),
- )
- return fields
- def rebuild_dataclass_fields(
- cls: type[PydanticDataclass],
- *,
- config_wrapper: ConfigWrapper,
- ns_resolver: NsResolver,
- typevars_map: Mapping[TypeVar, Any],
- ) -> dict[str, FieldInfo]:
- """Rebuild the (already present) dataclass fields by trying to reevaluate annotations.
- This function should be called whenever a dataclass with incomplete fields is encountered.
- Raises:
- NameError: If one of the annotations failed to evaluate.
- Note:
- This function *doesn't* mutate the dataclass fields in place, as it can be called during
- schema generation, where you don't want to mutate other dataclass's fields.
- """
- FieldInfo_ = import_cached_field_info()
- rebuilt_fields: dict[str, FieldInfo] = {}
- with ns_resolver.push(cls):
- for f_name, field_info in cls.__pydantic_fields__.items():
- if field_info._complete:
- rebuilt_fields[f_name] = field_info
- else:
- existing_desc = field_info.description
- ann = _typing_extra.eval_type(
- field_info._original_annotation,
- *ns_resolver.types_namespace,
- )
- ann = _generics.replace_types(ann, typevars_map)
- new_field = FieldInfo_.from_annotated_attribute(
- ann,
- field_info._original_assignment,
- _source=AnnotationSource.DATACLASS,
- )
- # The description might come from the docstring if `use_attribute_docstrings` was `True`:
- new_field.description = new_field.description if new_field.description is not None else existing_desc
- update_field_from_config(config_wrapper, f_name, new_field)
- rebuilt_fields[f_name] = new_field
- return rebuilt_fields
- def is_valid_field_name(name: str) -> bool:
- return not name.startswith('_')
- def is_valid_privateattr_name(name: str) -> bool:
- return name.startswith('_') and not name.startswith('__')
- def takes_validated_data_argument(
- default_factory: Callable[[], Any] | Callable[[dict[str, Any]], Any],
- ) -> TypeIs[Callable[[dict[str, Any]], Any]]:
- """Whether the provided default factory callable has a validated data parameter."""
- try:
- sig = signature(default_factory)
- except (ValueError, TypeError):
- # `inspect.signature` might not be able to infer a signature, e.g. with C objects.
- # In this case, we assume no data argument is present:
- return False
- parameters = list(sig.parameters.values())
- return len(parameters) == 1 and can_be_positional(parameters[0]) and parameters[0].default is Parameter.empty
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