def __new__( # type: ignore # noqa: CCR001
mcs: "ModelMetaclass", name: str, bases: Any, attrs: dict
) -> "ModelMetaclass":
"""
Metaclass used by ormar Models that performs configuration
and build of ormar Models.
Sets pydantic configuration.
Extract model_fields and convert them to pydantic FieldInfo,
updates class namespace.
Extracts settings and fields from parent classes.
Fetches methods decorated with @property_field decorator
to expose them later in dict().
Construct parent pydantic Metaclass/ Model.
If class has Meta class declared (so actual ormar Models) it also:
* populate sqlalchemy columns, pkname and tables from model_fields
* register reverse relationships on related models
* registers all relations in alias manager that populates table_prefixes
* exposes alias manager on each Model
* creates QuerySet for each model and exposes it on a class
:param name: name of current class
:type name: str
:param bases: base classes
:type bases: Tuple
:param attrs: class namespace
:type attrs: Dict
"""
attrs["Config"] = get_pydantic_base_orm_config()
attrs["__name__"] = name
attrs, model_fields = extract_annotations_and_default_vals(attrs)
for base in reversed(bases):
mod = base.__module__
if mod.startswith("ormar.models.") or mod.startswith("pydantic."):
continue
attrs, model_fields = extract_from_parents_definition(
base_class=base, curr_class=mcs, attrs=attrs, model_fields=model_fields
)
new_model = super().__new__( # type: ignore
mcs, name, bases, attrs
)
add_cached_properties(new_model)
if hasattr(new_model, "Meta"):
populate_default_options_values(new_model, model_fields)
check_required_meta_parameters(new_model)
add_property_fields(new_model, attrs)
register_signals(new_model=new_model)
populate_choices_validators(new_model)
if not new_model.Meta.abstract:
new_model = populate_meta_tablename_columns_and_pk(name, new_model)
populate_meta_sqlalchemy_table_if_required(new_model.Meta)
expand_reverse_relationships(new_model)
# TODO: iterate only related fields
for field in new_model.Meta.model_fields.values():
register_relation_in_alias_manager(field=field)
if new_model.Meta.pkname not in attrs["__annotations__"]:
field_name = new_model.Meta.pkname
attrs["__annotations__"][field_name] = Optional[int] # type: ignore
attrs[field_name] = None
new_model.__fields__[field_name] = get_pydantic_field(
field_name=field_name, model=new_model
)
new_model.Meta.alias_manager = alias_manager
return new_model
def extract_from_parents_definition( # noqa: CCR001
base_class: type,
curr_class: type,
attrs: Dict,
model_fields: Dict[str, Union[BaseField, ForeignKeyField, ManyToManyField]],
) -> Tuple[Dict, Dict]:
"""
Extracts fields from base classes if they have valid oramr fields.
If model was already parsed -> fields definitions need to be removed from class
cause pydantic complains about field re-definition so after first child
we need to extract from __parsed_fields__ not the class itself.
If the class is parsed first time annotations and field definition is parsed
from the class.__dict__.
If the class is a ormar.Model it is skipped.
:param base_class: one of the parent classes
:type base_class: Model or model parent class
:param curr_class: current constructed class
:type curr_class: Model or model parent class
:param attrs: new namespace for class being constructed
:type attrs: Dict
:param model_fields: ormar fields in defined in current class
:type model_fields: Dict[str, BaseField]
:return: updated attrs and model_fields
:rtype: Tuple[Dict, Dict]
"""
if hasattr(base_class, "Meta"):
base_class = cast(Type["Model"], base_class)
return copy_data_from_parent_model(
base_class=base_class,
curr_class=curr_class,
attrs=attrs,
model_fields=model_fields,
)
key = "__annotations__"
if hasattr(base_class, PARSED_FIELDS_KEY):
# model was already parsed -> fields definitions need to be removed from class
# cause pydantic complains about field re-definition so after first child
# we need to extract from __parsed_fields__ not the class itself
new_attrs, new_model_fields = getattr(base_class, PARSED_FIELDS_KEY)
new_fields = set(new_model_fields.keys())
model_fields = update_attrs_and_fields(
attrs=attrs,
new_attrs=new_attrs,
model_fields=model_fields,
new_model_fields=new_model_fields,
new_fields=new_fields,
)
return attrs, model_fields
potential_fields = get_potential_fields(base_class.__dict__)
if potential_fields:
# parent model has ormar fields defined and was not parsed before
new_attrs = {key: {k: v for k, v in base_class.__dict__.get(key, {}).items()}}
new_attrs.update(potential_fields)
new_fields = set(potential_fields.keys())
for name in new_fields:
delattr(base_class, name)
new_attrs, new_model_fields = extract_annotations_and_default_vals(new_attrs)
setattr(base_class, PARSED_FIELDS_KEY, (new_attrs, new_model_fields))
model_fields = update_attrs_and_fields(
attrs=attrs,
new_attrs=new_attrs,
model_fields=model_fields,
new_model_fields=new_model_fields,
new_fields=new_fields,
)
return attrs, model_fields
