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@antoine-tran
Last active August 16, 2024 21:30
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Update a dataclass inplace
from typing import Any, ClassVar, Final, Mapping, Protocol, TypeAlias, TypeGuard, TypeVar
import typing_extensions
class DataClass(Protocol):
"""Represents a data class object."""
__dataclass_fields__: ClassVar[dict[str, Field[Any]]]
def is_dataclass_instance(obj: Any) -> TypeGuard[DataClass]:
"""Return ``True`` if ``obj`` is of type :class:`DataClass`."""
return is_dataclass(obj) and not isinstance(obj, type)
def update_dataclass(
obj: DataClass,
overrides: Mapping[str, Any],
) -> List[str]:
"""Update ``obj`` with the data contained in ``overrides`` Return the unknown fields.
:param obj:
The data class instance to update.
:param overrides:
The dictionary containing the data to set in ``obj``.
"""
unknown_fields: List[str] = []
field_path: List[str] = []
def update(obj_: DataClass, overrides_: Mapping[str, Any]) -> None:
overrides_copy = {**overrides_}
for field in fields(obj_):
value = getattr(obj_, field.name)
try:
override = overrides_copy.pop(field.name)
except KeyError:
continue
# Recursively traverse child dataclasses.
if override is not None and is_dataclass_instance(value):
if not isinstance(override, Mapping):
pathname = ".".join(field_path + [field.name])
raise RuntimeError(
pathname, f"The field '{pathname}' is expected to be of type `{type(value)}`, but is of type `{type(override)}` instead." # fmt: skip
)
field_path.append(field.name)
update(value, override)
field_path.pop()
else:
setattr(obj_, field.name, override)
if overrides_copy:
unknown_fields.extend(
".".join(field_path + [name]) for name in overrides_copy
)
update(obj, overrides)
unknown_fields.sort()
return unknown_fields
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