Source code
from __future__ import annotations
import abc
import contextlib
import enum
import itertools
import linecache
import sys
import types
import unicodedata
import weakref
from collections.abc import Callable, Mapping
from functools import cached_property
from typing import Any, NamedTuple, TypeVar
from . import _compat, _config, setters
from ._compat import (
PY_3_11_PLUS,
PY_3_13_PLUS,
_AnnotationExtractor,
_get_annotations,
_lazy_is_generator,
get_generic_base,
)
from .exceptions import (
DefaultAlreadySetError,
FrozenInstanceError,
NotAnAttrsClassError,
UnannotatedAttributeError,
)
class ClassProps:
"""
Effective class properties as derived from parameters to `attr.s()` or
`define()` decorators.
This is the same data structure that *attrs* uses internally to decide how
to construct the final class.
Warning:
This feature is currently **experimental** and is not covered by our
strict backwards-compatibility guarantees.
Attributes:
is_exception (bool):
Whether the class is treated as an exception class.
is_slotted (bool):
Whether the class is `slotted <slotted classes>`.
has_weakref_slot (bool):
Whether the class has a slot for weak references.
is_frozen (bool):
Whether the class is frozen.
kw_only (KeywordOnly):
Whether / how the class enforces keyword-only arguments on the
``__init__`` method.
collected_fields_by_mro (bool):
Whether the class fields were collected by method resolution order.
That is, correctly but unlike `dataclasses`.
added_init (bool):
Whether the class has an *attrs*-generated ``__init__`` method.
added_repr (bool):
Whether the class has an *attrs*-generated ``__repr__`` method.
added_eq (bool):
Whether the class has *attrs*-generated equality methods.
added_ordering (bool):
Whether the class has *attrs*-generated ordering methods.
hashability (Hashability): How `hashable <hashing>` the class is.
added_match_args (bool):
Whether the class supports positional `match <match>` over its
fields.
added_str (bool):
Whether the class has an *attrs*-generated ``__str__`` method.
added_pickling (bool):
Whether the class has *attrs*-generated ``__getstate__`` and
``__setstate__`` methods for `pickle`.
on_setattr_hook (Callable[[Any, Attribute[Any], Any], Any] | None):
The class's ``__setattr__`` hook.
field_transformer (Callable[[Attribute[Any]], Attribute[Any]] | None):
The class's `field transformers <transform-fields>`.
.. versionadded:: 25.4.0
"""
class Hashability(enum.Enum):
"""
The hashability of a class.
.. versionadded:: 25.4.0
"""
HASHABLE = "hashable"
"""Write a ``__hash__``."""
HASHABLE_CACHED = "hashable_cache"
"""Write a ``__hash__`` and cache the hash."""
UNHASHABLE = "unhashable"
"""Set ``__hash__`` to ``None``."""
LEAVE_ALONE = "leave_alone"
"""Don't touch ``__hash__``."""
class KeywordOnly(enum.Enum):
"""
How attributes should be treated regarding keyword-only parameters.
.. versionadded:: 25.4.0
"""
NO = "no"
"""Attributes are not keyword-only."""
YES = "yes"
"""Attributes in current class without kw_only=False are keyword-only."""
FORCE = "force"
"""All attributes are keyword-only."""
__slots__ = ( # noqa: RUF023 -- order matters for __init__
"is_exception",
"is_slotted",
"has_weakref_slot",
"is_frozen",
"kw_only",
"collected_fields_by_mro",
"added_init",
"added_repr",
"added_eq",
"added_ordering",
"hashability",
"added_match_args",
"added_str",
"added_pickling",
"on_setattr_hook",
"field_transformer",
)
def __init__(
self,
is_exception,
is_slotted,
has_weakref_slot,
is_frozen,
kw_only,
collected_fields_by_mro,
added_init,
added_repr,
added_eq,
added_ordering,
hashability,
added_match_args,
added_str,
added_pickling,
on_setattr_hook,
field_transformer,
):
self.is_exception = is_exception
self.is_slotted = is_slotted
self.has_weakref_slot = has_weakref_slot
self.is_frozen = is_frozen
self.kw_only = kw_only
self.collected_fields_by_mro = collected_fields_by_mro
self.added_init = added_init
self.added_repr = added_repr
self.added_eq = added_eq
self.added_ordering = added_ordering
self.hashability = hashability
self.added_match_args = added_match_args
self.added_str = added_str
self.added_pickling = added_pickling
self.on_setattr_hook = on_setattr_hook
self.field_transformer = field_transformer
@property
def is_hashable(self):
return (
self.hashability is ClassProps.Hashability.HASHABLE
or self.hashability is ClassProps.Hashability.HASHABLE_CACHED
)