8000 Recollect fields during rebuild if collection failed · pydantic/pydantic@9f735a6 · GitHub
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Recollect fields during rebuild if collection failed
This is the biggest change in this PR, and the hardest to reason about and the trickiest to implement. Instead of re-evaluating annotations on a field-by-field basis, we assume all fields have their annotation evaluated (and consequently the `FieldInfo` attributes -- some of them set depending on the annotation -- are correct). To do so, we collect model fields (if necessary, thanks to the new `__pydantic_fields_complete__` attribute) in `_model_schema()`, and then have `_common_field_schema()` called with a fully built `FieldInfo` instance (this mimics what is done for dataclasses). When `model_rebuild()` is called, we also want to recollect fields if it wasn't successful the first time. This introduces challenges, such as keeping the model assignments to be able to recollect fields and call `FieldInfo.from_annotated_attribute()`.
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‎pydantic/_internal/_fields.py

Lines changed: 11 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -78,7 +78,7 @@ def collect_model_fields( # noqa: C901
7878
ns_resolver: NsResolver | None,
7979
*,
8080
typevars_map: dict[Any, Any] | None = None,
81-
) -> tuple[dict[str, FieldInfo], set[str]]:
81+
) -> tuple[dict[str, FieldInfo], set[str], bool]:
8282
"""Collect the fields of a nascent pydantic model.
8383
8484
Also collect the names of any ClassVars present in the type hints.
@@ -92,7 +92,8 @@ def collect_model_fields( # noqa: C901
9292
typevars_map: A dictionary mapping type variables to their concrete types.
9393
9494
Returns:
95-
A tuple contains fields and class variables.
95+
A three-tuple containing the model fields, the names of the class variables and a boolean indicating if
96+
annotation evaluation a succeeded.
9697
9798
Raises:
9899
NameError:
@@ -110,6 +111,7 @@ def collect_model_fields( # noqa: C901
110111
parent_fields_lookup.update(model_fields)
111112

112113
type_hints = _typing_extra.get_model_type_hints(cls, ns_resolver=ns_resolver)
114+
evaluation_suceeded = True
113115

114116
# https://docs.python.org/3/howto/annotations.html#accessing-the-annotations-dict-of-an-object-in-python-3-9-and-older
115117
# annotations is only used for finding fields in parent classes
@@ -179,6 +181,12 @@ def collect_model_fields( # noqa: C901
179181
f"Unexpected field with name {ann_name!r}; only 'root' is allowed as a field of a `RootModel`"
180182
)
181183

184+
# At this point, the field is not a private attribute/class variable. If the type annotation did not
185+
# evaluate successfully, we set the `evaluation_suceeded` flag that is used to decide if we continue with
186+
# core schema generation:
187+
if evaluation_suceeded and not evaluated:
188+
evaluation_suceeded = evaluated
189+
182190
# when building a generic model with `MyModel[int]`, the generic_origin check makes sure we don't get
183191
# "... shadows an attribute" warnings
184192
generic_origin = getattr(cls, '__pydantic_generic_metadata__', {}).get('origin')
@@ -209,7 +217,6 @@ def collect_model_fields( # noqa: C901
209217
if assigned_value is PydanticUndefined:
210218
if ann_name in annotations:
211219
field_info = FieldInfo_.from_annotation(ann_type)
212-
field_info.evaluated = evaluated
213220
else:
214221
# if field has no default value and is not in __annotations__ this means that it is
215222
# defined in a base class and we can take it from there
@@ -222,7 +229,6 @@ def collect_model_fields( # noqa: C901
222229
# generated thanks to models not being fully defined while initializing recursive models.
223230
# Nothing stops us from just creating a new FieldInfo for this type hint, so we do this.
224231
field_info = FieldInfo_.from_annotation(ann_type)
225-
field_info.evaluated = evaluated
226232
else:
227233
_warn_on_nested_alias_in_annotation(ann_type, ann_name)
228234
if isinstance(assigned_value, FieldInfo_) and ismethoddescriptor(assigned_value.default):
@@ -234,14 +240,6 @@ def collect_model_fields( # noqa: C901
234240
assigned_value.default = assigned_value.default.__get__(None, cls)
235241

236242
field_info = FieldInfo_.from_annotated_attribute(ann_type, assigned_value)
237-
field_info.evaluated = evaluated
238-
# attributes which are fields are removed from the class namespace:
239-
# 1. To match the behaviour of annotation-only fields
240-
# 2. To avoid false positives in the NameError check above
241-
try:
242-
delattr(cls, ann_name)
243-
except AttributeError:
244-
pass # indicates the attribute was on a parent class
245243

246244
# Use cls.__dict__['__pydantic_decorators__'] instead of cls.__pydantic_decorators__
247245
# to make sure the decorators have already been built for this exact class
@@ -256,7 +254,7 @@ def collect_model_fields( # noqa: C901
256254

257255
if config_wrapper.use_attribute_docstrings:
258256
_update_fields_from_docstrings(cls, fields)
259-
return fields, class_vars
257+
return fields, class_vars, evaluation_suceeded
260258

261259

262260
def _warn_on_nested_alias_in_annotation(ann_type: type[Any], ann_name: str) -> None:

‎pydantic/_internal/_generate_schema.py

Lines changed: 33 additions & 41 deletions
Original file line numberDiff line numberDiff line change
@@ -84,9 +84,9 @@
8484
inspect_validator,
8585
)
8686
from ._docs_extraction import extract_docstrings_from_cls
87-
from ._fields import collect_dataclass_fields, takes_validated_data_argument
87+
from ._fields import collect_dataclass_fields, collect_model_fields, takes_validated_data_argument
8888
from ._forward_ref import PydanticRecursiveRef
89-
from ._generics import get_standard_typevars_map, has_instance_in_type, replace_types
89+
from ._generics import get_standard_typevars_map, replace_types
9090
from ._import_utils import import_cached_base_model, import_cached_field_info
9191
from ._mock_val_ser import MockCoreSchema
9292
from ._namespace_utils import NamespacesTuple, NsResolver
@@ -695,6 +695,8 @@ def generate_schema(
695695

696696
def _model_schema(self, cls: type[BaseModel]) -> core_schema.CoreSchema:
697697
"""Generate schema for a Pydantic model."""
698+
BaseModel_ = import_cached_base_model()
699+
698700
with self.defs.get_schema_or_ref(cls) as (model_ref, maybe_schema):
699701
if maybe_schema is not None:
700702
return maybe_schema
@@ -716,22 +718,38 @@ def _model_schema(self, cls: type[BaseModel]) -> core_schema.CoreSchema:
716718
else:
717719
return schema
718720

719-
fields = getattr(cls, '__pydantic_fields__', {})
720-
decorators = cls.__pydantic_decorators__
721-
computed_fields = decorators.computed_fields
722-
check_decorator_fields_exist(
723-
chain(
724-
decorators.field_validators.values(),
725-
decorators.field_serializers.values(),
726-
decorators.validators.values(),
727-
),
728-
{*fields.keys(), *computed_fields.keys()},
729-
)
730721
config_wrapper = ConfigWrapper(cls.model_config, check=False)
731-
core_config = config_wrapper.core_config(title=cls.__name__)
732-
model_validators = decorators.model_validators.values()
733722

734723
with self._config_wrapper_stack.push(config_wrapper), self._ns_resolver.push(cls):
724+
core_config = self._config_wrapper.core_config(title=cls.__name__)
725+
726+
if cls.__pydantic_fields_complete__ or cls is BaseModel_:
727+
fields = getattr(cls, '__pydantic_fields__', {})
728+
else:
729+
fields, _, evaluation_suceeded = collect_model_fields(
730+
cls,
731+
config_wrapper=self._config_wrapper,
732+
ns_resolver=self._ns_resolver,
733+
typevars_map=self._typevars_map,
734+
)
735+
if not evaluation_suceeded:
736+
raise PydanticUndefinedAnnotation(
737+
name='<unknown>', message=f'An annotation is not defined in model {cls}'
738+
)
739+
740+
decorators = cls.__pydantic_decorators__
741+
computed_fields = decorators.computed_fields
742+
check_decorator_fields_exist(
743+
chain(
744+
decorators.field_validators.values(),
745+
decorators.field_serializers.values(),
746+
decorators.validators.values(),
747+
),
748+
{*fields.keys(), *computed_fields.keys()},
749+
)
750+
751+
model_validators = decorators.model_validators.values()
752+
735753
extras_schema = None
736754
if core_config.get('extra_fields_behavior') == 'allow':
737755
assert cls.__mro__[0] is cls
@@ -1296,32 +1314,6 @@ def _apply_field_title_generator_to_field_info(
12961314
def _common_field_schema( # C901
12971315
self, name: str, field_info: FieldInfo, decorators: DecoratorInfos
12981316
) -> _CommonField:
1299-
# Update FieldInfo annotation if appropriate:
1300-
FieldInfo = import_cached_field_info()
1301-
if not field_info.evaluated:
1302-
# TODO Can we use field_info.apply_typevars_map here?
1303-
try:
1304-
evaluated_type = _typing_extra.eval_type(field_info.annotation, *self._types_namespace)
1305-
except NameError as e:
1306-
raise PydanticUndefinedAnnotation.from_name_error(e) from e
1307-
evaluated_type = replace_types(evaluated_type, self._typevars_map)
1308-
field_info.evaluated = True
1309-
if not has_instance_in_type(evaluated_type, PydanticRecursiveRef):
1310-
new_field_info = FieldInfo.from_annotation(evaluated_type)
1311-
field_info.annotation = new_field_info.annotation
1312-
1313-
# Handle any field info attributes that may have been obtained from now-resolved annotations
1314-
for k, v in new_field_info._attributes_set.items():
1315-
# If an attribute is already set, it means it was set by assigning to a call to Field (or just a
1316-
# default value), and that should take the highest priority. So don't overwrite existing attributes.
1317-
# We skip over "attributes" that are present in the metadata_lookup dict because these won't
1318-
# actually end up as attributes of the `FieldInfo` instance.
1319-
if k not in field_info._attributes_set and k not in field_info.metadata_lookup:
1320-
setattr(field_info, k, v)
1321-
1322-
# Finally, ensure the field info also reflects all the `_attributes_set` that are actually metadata.
1323-
field_info.metadata = [*new_field_info.metadata, *field_info.metadata]
1324-
13251317
source_type, annotations = field_info.annotation, field_info.metadata
13261318

13271319
def set_discriminator(schema: CoreSchema) -> CoreSchema:

‎pydantic/_internal/_model_construction.py

Lines changed: 37 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -203,7 +203,9 @@ def wrapped_model_post_init(self: BaseModel, context: Any, /) -> None:
203203
'parameters': parameters,
204204
}
205205

206-
cls.__pydantic_complete__ = False # Ensure this specific class gets completed
206+
# Do not inherit these attributes from the parent model, if any:
207+
cls.__pydantic_complete__ = False
208+
cls.__pydantic_fields_complete__ = False
207209

208210
# preserve `__set_name__` protocol defined in https://peps.python.org/pep-0487
209211
# for attributes not in `new_namespace` (e.g. private attributes)
@@ -216,9 +218,6 @@ def wrapped_model_post_init(self: BaseModel, context: Any, /) -> None:
216218
if isinstance(parent_namespace, dict):
217219
parent_namespace = unpack_lenient_weakvaluedict(parent_namespace)
218220

219-
if config_wrapper.frozen and '__hash__' not in namespace:
220-
set_default_hash_func(cls, bases)
221-
222221
complete_model_class(
223222
cls,
224223
config_wrapper,
@@ -227,6 +226,9 @@ def wrapped_model_post_init(self: BaseModel, context: Any, /) -> None:
227226
create_model_module=_create_model_module,
228227
)
229228

229+
if config_wrapper.frozen and '__hash__' not in namespace:
230+
set_default_hash_func(cls, bases)
231+
230232
# If this is placed before the complete_model_class call above,
231233
# the generic computed fields return type is set to PydanticUndefined
232234
cls.__pydantic_computed_fields__ = {
@@ -509,7 +511,7 @@ def set_model_fields(
509511
cls: type[BaseModel],
510512
config_wrapper: ConfigWrapper,
511513
ns_resolver: NsResolver | None,
512-
) -> None:
514+
) -> bool:
513515
"""Collect and set `cls.__pydantic_fields__` and `cls.__class_vars__`.
514516
515517
Args:
@@ -518,7 +520,22 @@ def set_model_fields(
518520
ns_resolver: Namespace resolver to use when getting model annotations.
519521
"""
520522
typevars_map = get_model_typevars_map(cls)
521-
fields, class_vars = collect_model_fields(cls, config_wrapper, ns_resolver, typevars_map=typevars_map)
523+
fields, class_vars, evaluation_suceeded = collect_model_fields(
524+
cls, config_wrapper, ns_resolver, typevars_map=typevars_map
525+
)
526+
527+
if evaluation_suceeded:
528+
# attributes which are fields are removed from the class namespace:
529+
# 1. To match the behaviour of annotation-only fields
530+
# 2. To avoid false positives in the NameError check above.
531+
# We only remove them if annotation evaluation suceeded, as otherwise
532+
# fields collection may be performed one more time, and we to keep assignments
533+
# (so that we can call `FieldInfo.from_annotated_attribute()`).
534+
for ann_name in fields:
535+
try:
536+
delattr(cls, ann_name)
537+
except AttributeError: # indicates the attribute was on a parent class
538+
pass
522539

523540
cls.__pydantic_fields__ = fields
524541
cls.__class_vars__.update(class_vars)
@@ -535,6 +552,8 @@ def set_model_fields(
535552
if value is not None and value.default is not PydanticUndefined:
536553
setattr(cls, k, value.default)
537554

555+
return evaluation_suceeded
556+
538557

539558
def complete_model_class(
540559
cls: type[BaseModel],
@@ -563,12 +582,22 @@ def complete_model_class(
563582
PydanticUndefinedAnnotation: If `PydanticUndefinedAnnotation` occurs in`__get_pydantic_core_schema__`
564583
and `raise_errors=True`.
565584
"""
585+
if not cls.__pydantic_fields_complete__:
586+
evaluation_suceeded = set_model_fields(cls, config_wrapper=config_wrapper, ns_resolver=ns_resolver)
587+
if not evaluation_suceeded:
588+
if raise_errors:
589+
raise PydanticUndefinedAnnotation(
590+
name='<unknown>', message=f'An annotation is not defined in model {cls}'
591+
)
592+
set_model_mocks(cls)
593+
return False
594+
595+
cls.__pydantic_fields_complete__ = True
596+
566597
if config_wrapper.defer_build:
567598
set_model_mocks(cls)
568599
return False
569600

570-
set_model_fields(cls, config_wrapper=config_wrapper, ns_resolver=ns_resolver)
571-
572601
typevars_map = get_model_typevars_map(cls)
573602
gen_schema = GenerateSchema(
574603
config_wrapper,

‎pydantic/fields.py

Lines changed: 1 addition & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -155,7 +155,6 @@ class FieldInfo(_repr.Representation):
155155

156156
__slots__ = (
157157
'annotation',
158-
'evaluated',
159158
'default',
160159
'default_factory',
161160
'alias',
@@ -209,7 +208,6 @@ def __init__(self, **kwargs: Unpack[_FieldInfoInputs]) -> None:
209208
self._attributes_set = {k: v for k, v in kwargs.items() if v is not _Unset}
210209
kwargs = {k: _DefaultValues.get(k) if v is _Unset else v for k, v in kwargs.items()} # type: ignore
211210
self.annotation = kwargs.get('annotation')
212-
self.evaluated = False
213211

214212
default = kwargs.pop('default', PydanticUndefined)
215213
if default is Ellipsis:
@@ -680,7 +678,7 @@ def __repr_args__(self) -> ReprArgs:
680678
for s in self.__slots__:
681679
# TODO: properly make use of the protocol (https://rich.readthedocs.io/en/stable/pretty.html#rich-repr-protocol)
682680
# By yielding a three-tuple:
683-
if s in ('_attributes_set', 'annotation', 'evaluated'):
681+
if s in ('_attributes_set', 'annotation'):
684682
continue
685683
elif s == 'metadata' and not self.metadata:
686684
continue

‎pydantic/main.py

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -147,6 +147,11 @@ class BaseModel(metaclass=_model_construction.ModelMetaclass):
147147
__pydantic_complete__: ClassVar[bool] = False
148148
"""Whether model building is completed, or if there are still undefined fields."""
149149

150+
__pydantic_fields_complete__: ClassVar[bool] = False
151+
"""Whether the fields where successfully collected. This is a private attribute, not meant
152+
to be used outside Pydantic.
153+
"""
154+
150155
__pydantic_core_schema__: ClassVar[CoreSchema]
151156
"""The core schema of the model."""
152157

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