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3015 lines (2495 loc) · 96 KB
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# SPDX-License-Identifier: MIT
import contextlib
import copy
import enum
import inspect
import linecache
import sys
import types
import typing
from operator import itemgetter
# We need to import _compat itself in addition to the _compat members to avoid
# having the thread-local in the globals here.
from . import _compat, _config, setters
from ._compat import (
PY310,
_AnnotationExtractor,
get_generic_base,
set_closure_cell,
)
from .exceptions import (
DefaultAlreadySetError,
FrozenInstanceError,
NotAnAttrsClassError,
UnannotatedAttributeError,
)
# This is used at least twice, so cache it here.
_obj_setattr = object.__setattr__
_init_converter_pat = "__attr_converter_%s"
_init_factory_pat = "__attr_factory_%s"
_classvar_prefixes = (
"typing.ClassVar",
"t.ClassVar",
"ClassVar",
"typing_extensions.ClassVar",
)
# we don't use a double-underscore prefix because that triggers
# name mangling when trying to create a slot for the field
# (when slots=True)
_hash_cache_field = "_attrs_cached_hash"
_empty_metadata_singleton = types.MappingProxyType({})
# Unique object for unequivocal getattr() defaults.
_sentinel = object()
_ng_default_on_setattr = setters.pipe(setters.convert, setters.validate)
class _Nothing(enum.Enum):
"""
Sentinel to indicate the lack of a value when ``None`` is ambiguous.
If extending attrs, you can use ``typing.Literal[NOTHING]`` to show
that a value may be ``NOTHING``.
.. versionchanged:: 21.1.0 ``bool(NOTHING)`` is now False.
.. versionchanged:: 22.2.0 ``NOTHING`` is now an ``enum.Enum`` variant.
"""
NOTHING = enum.auto()
def __repr__(self):
return "NOTHING"
def __bool__(self):
return False
NOTHING = _Nothing.NOTHING
"""
Sentinel to indicate the lack of a value when ``None`` is ambiguous.
"""
class _CacheHashWrapper(int):
"""
An integer subclass that pickles / copies as None
This is used for non-slots classes with ``cache_hash=True``, to avoid
serializing a potentially (even likely) invalid hash value. Since ``None``
is the default value for uncalculated hashes, whenever this is copied,
the copy's value for the hash should automatically reset.
See GH #613 for more details.
"""
def __reduce__(self, _none_constructor=type(None), _args=()): # noqa: B008
return _none_constructor, _args
def attrib(
default=NOTHING,
validator=None,
repr=True,
cmp=None,
hash=None,
init=True,
metadata=None,
type=None,
converter=None,
factory=None,
kw_only=False,
eq=None,
order=None,
on_setattr=None,
alias=None,
):
"""
Create a new attribute on a class.
.. warning::
Does *not* do anything unless the class is also decorated with `attr.s`
/ `attrs.define` / and so on!
Please consider using `attrs.field` in new code (``attr.ib`` will *never*
go away, though).
:param default: A value that is used if an *attrs*-generated ``__init__``
is used and no value is passed while instantiating or the attribute is
excluded using ``init=False``.
If the value is an instance of `attrs.Factory`, its callable will be
used to construct a new value (useful for mutable data types like lists
or dicts).
If a default is not set (or set manually to `attrs.NOTHING`), a value
*must* be supplied when instantiating; otherwise a `TypeError` will be
raised.
The default can also be set using decorator notation as shown below.
.. seealso:: `defaults`
:param callable factory: Syntactic sugar for
``default=attr.Factory(factory)``.
:param validator: `callable` that is called by *attrs*-generated
``__init__`` methods after the instance has been initialized. They
receive the initialized instance, the :func:`~attrs.Attribute`, and the
passed value.
The return value is *not* inspected so the validator has to throw an
exception itself.
If a `list` is passed, its items are treated as validators and must all
pass.
Validators can be globally disabled and re-enabled using
`attrs.validators.get_disabled` / `attrs.validators.set_disabled`.
The validator can also be set using decorator notation as shown below.
.. seealso:: :ref:`validators`
:type validator: `callable` or a `list` of `callable`\\ s.
:param repr: Include this attribute in the generated ``__repr__`` method.
If ``True``, include the attribute; if ``False``, omit it. By default,
the built-in ``repr()`` function is used. To override how the attribute
value is formatted, pass a ``callable`` that takes a single value and
returns a string. Note that the resulting string is used as-is, i.e. it
will be used directly *instead* of calling ``repr()`` (the default).
:type repr: a `bool` or a `callable` to use a custom function.
:param eq: If ``True`` (default), include this attribute in the generated
``__eq__`` and ``__ne__`` methods that check two instances for
equality. To override how the attribute value is compared, pass a
``callable`` that takes a single value and returns the value to be
compared.
.. seealso:: `comparison`
:type eq: a `bool` or a `callable`.
:param order: If ``True`` (default), include this attributes in the
generated ``__lt__``, ``__le__``, ``__gt__`` and ``__ge__`` methods. To
override how the attribute value is ordered, pass a ``callable`` that
takes a single value and returns the value to be ordered.
.. seealso:: `comparison`
:type order: a `bool` or a `callable`.
:param cmp: Setting *cmp* is equivalent to setting *eq* and *order* to the
same value. Must not be mixed with *eq* or *order*.
.. seealso:: `comparison`
:type cmp: a `bool` or a `callable`.
:param bool | None hash: Include this attribute in the generated
``__hash__`` method. If ``None`` (default), mirror *eq*'s value. This
is the correct behavior according the Python spec. Setting this value
to anything else than ``None`` is *discouraged*.
.. seealso:: `hashing`
:param bool init: Include this attribute in the generated ``__init__``
method. It is possible to set this to ``False`` and set a default
value. In that case this attributed is unconditionally initialized
with the specified default value or factory.
.. seealso:: `init`
:param callable converter: `callable` that is called by *attrs*-generated
``__init__`` methods to convert attribute's value to the desired
format. It is given the passed-in value, and the returned value will
be used as the new value of the attribute. The value is converted
before being passed to the validator, if any.
.. seealso:: :ref:`converters`
:param dict | None metadata: An arbitrary mapping, to be used by
third-party components. See `extending-metadata`.
:param type: The type of the attribute. Nowadays, the preferred method to
specify the type is using a variable annotation (see :pep:`526`). This
argument is provided for backward compatibility. Regardless of the
approach used, the type will be stored on ``Attribute.type``.
Please note that *attrs* doesn't do anything with this metadata by
itself. You can use it as part of your own code or for `static type
checking <types>`.
:param bool kw_only: Make this attribute keyword-only in the generated
``__init__`` (if ``init`` is ``False``, this parameter is ignored).
:param on_setattr: Allows to overwrite the *on_setattr* setting from
`attr.s`. If left `None`, the *on_setattr* value from `attr.s` is used.
Set to `attrs.setters.NO_OP` to run **no** `setattr` hooks for this
attribute -- regardless of the setting in `attr.s`.
:type on_setattr: `callable`, or a list of callables, or `None`, or
`attrs.setters.NO_OP`
:param str | None alias: Override this attribute's parameter name in the
generated ``__init__`` method. If left `None`, default to ``name``
stripped of leading underscores. See `private-attributes`.
.. versionadded:: 15.2.0 *convert*
.. versionadded:: 16.3.0 *metadata*
.. versionchanged:: 17.1.0 *validator* can be a ``list`` now.
.. versionchanged:: 17.1.0
*hash* is ``None`` and therefore mirrors *eq* by default.
.. versionadded:: 17.3.0 *type*
.. deprecated:: 17.4.0 *convert*
.. versionadded:: 17.4.0 *converter* as a replacement for the deprecated
*convert* to achieve consistency with other noun-based arguments.
.. versionadded:: 18.1.0
``factory=f`` is syntactic sugar for ``default=attr.Factory(f)``.
.. versionadded:: 18.2.0 *kw_only*
.. versionchanged:: 19.2.0 *convert* keyword argument removed.
.. versionchanged:: 19.2.0 *repr* also accepts a custom callable.
.. deprecated:: 19.2.0 *cmp* Removal on or after 2021-06-01.
.. versionadded:: 19.2.0 *eq* and *order*
.. versionadded:: 20.1.0 *on_setattr*
.. versionchanged:: 20.3.0 *kw_only* backported to Python 2
.. versionchanged:: 21.1.0
*eq*, *order*, and *cmp* also accept a custom callable
.. versionchanged:: 21.1.0 *cmp* undeprecated
.. versionadded:: 22.2.0 *alias*
"""
eq, eq_key, order, order_key = _determine_attrib_eq_order(
cmp, eq, order, True
)
if hash is not None and hash is not True and hash is not False:
msg = "Invalid value for hash. Must be True, False, or None."
raise TypeError(msg)
if factory is not None:
if default is not NOTHING:
msg = (
"The `default` and `factory` arguments are mutually exclusive."
)
raise ValueError(msg)
if not callable(factory):
msg = "The `factory` argument must be a callable."
raise ValueError(msg)
default = Factory(factory)
if metadata is None:
metadata = {}
# Apply syntactic sugar by auto-wrapping.
if isinstance(on_setattr, (list, tuple)):
on_setattr = setters.pipe(*on_setattr)
if validator and isinstance(validator, (list, tuple)):
validator = and_(*validator)
if converter and isinstance(converter, (list, tuple)):
converter = pipe(*converter)
return _CountingAttr(
default=default,
validator=validator,
repr=repr,
cmp=None,
hash=hash,
init=init,
converter=converter,
metadata=metadata,
type=type,
kw_only=kw_only,
eq=eq,
eq_key=eq_key,
order=order,
order_key=order_key,
on_setattr=on_setattr,
alias=alias,
)
def _compile_and_eval(script, globs, locs=None, filename=""):
"""
"Exec" the script with the given global (globs) and local (locs) variables.
"""
bytecode = compile(script, filename, "exec")
eval(bytecode, globs, locs)
def _make_method(name, script, filename, globs):
"""
Create the method with the script given and return the method object.
"""
locs = {}
# In order of debuggers like PDB being able to step through the code,
# we add a fake linecache entry.
count = 1
base_filename = filename
while True:
linecache_tuple = (
len(script),
None,
script.splitlines(True),
filename,
)
old_val = linecache.cache.setdefault(filename, linecache_tuple)
if old_val == linecache_tuple:
break
filename = f"{base_filename[:-1]}-{count}>"
count += 1
_compile_and_eval(script, globs, locs, filename)
return locs[name]
def _make_attr_tuple_class(cls_name, attr_names):
"""
Create a tuple subclass to hold `Attribute`s for an `attrs` class.
The subclass is a bare tuple with properties for names.
class MyClassAttributes(tuple):
__slots__ = ()
x = property(itemgetter(0))
"""
attr_class_name = f"{cls_name}Attributes"
attr_class_template = [
f"class {attr_class_name}(tuple):",
" __slots__ = ()",
]
if attr_names:
for i, attr_name in enumerate(attr_names):
attr_class_template.append(
f" {attr_name} = _attrs_property(_attrs_itemgetter({i}))"
)
else:
attr_class_template.append(" pass")
globs = {"_attrs_itemgetter": itemgetter, "_attrs_property": property}
_compile_and_eval("\n".join(attr_class_template), globs)
return globs[attr_class_name]
# Tuple class for extracted attributes from a class definition.
# `base_attrs` is a subset of `attrs`.
_Attributes = _make_attr_tuple_class(
"_Attributes",
[
# all attributes to build dunder methods for
"attrs",
# attributes that have been inherited
"base_attrs",
# map inherited attributes to their originating classes
"base_attrs_map",
],
)
def _is_class_var(annot):
"""
Check whether *annot* is a typing.ClassVar.
The string comparison hack is used to avoid evaluating all string
annotations which would put attrs-based classes at a performance
disadvantage compared to plain old classes.
"""
annot = str(annot)
# Annotation can be quoted.
if annot.startswith(("'", '"')) and annot.endswith(("'", '"')):
annot = annot[1:-1]
return annot.startswith(_classvar_prefixes)
def _has_own_attribute(cls, attrib_name):
"""
Check whether *cls* defines *attrib_name* (and doesn't just inherit it).
"""
attr = getattr(cls, attrib_name, _sentinel)
if attr is _sentinel:
return False
for base_cls in cls.__mro__[1:]:
a = getattr(base_cls, attrib_name, None)
if attr is a:
return False
return True
def _get_annotations(cls):
"""
Get annotations for *cls*.
"""
if _has_own_attribute(cls, "__annotations__"):
return cls.__annotations__
return {}
def _collect_base_attrs(cls, taken_attr_names):
"""
Collect attr.ibs from base classes of *cls*, except *taken_attr_names*.
"""
base_attrs = []
base_attr_map = {} # A dictionary of base attrs to their classes.
# Traverse the MRO and collect attributes.
for base_cls in reversed(cls.__mro__[1:-1]):
for a in getattr(base_cls, "__attrs_attrs__", []):
if a.inherited or a.name in taken_attr_names:
continue
a = a.evolve(inherited=True) # noqa: PLW2901
base_attrs.append(a)
base_attr_map[a.name] = base_cls
# For each name, only keep the freshest definition i.e. the furthest at the
# back. base_attr_map is fine because it gets overwritten with every new
# instance.
filtered = []
seen = set()
for a in reversed(base_attrs):
if a.name in seen:
continue
filtered.insert(0, a)
seen.add(a.name)
return filtered, base_attr_map
def _collect_base_attrs_broken(cls, taken_attr_names):
"""
Collect attr.ibs from base classes of *cls*, except *taken_attr_names*.
N.B. *taken_attr_names* will be mutated.
Adhere to the old incorrect behavior.
Notably it collects from the front and considers inherited attributes which
leads to the buggy behavior reported in #428.
"""
base_attrs = []
base_attr_map = {} # A dictionary of base attrs to their classes.
# Traverse the MRO and collect attributes.
for base_cls in cls.__mro__[1:-1]:
for a in getattr(base_cls, "__attrs_attrs__", []):
if a.name in taken_attr_names:
continue
a = a.evolve(inherited=True) # noqa: PLW2901
taken_attr_names.add(a.name)
base_attrs.append(a)
base_attr_map[a.name] = base_cls
return base_attrs, base_attr_map
def _transform_attrs(
cls, these, auto_attribs, kw_only, collect_by_mro, field_transformer
):
"""
Transform all `_CountingAttr`s on a class into `Attribute`s.
If *these* is passed, use that and don't look for them on the class.
*collect_by_mro* is True, collect them in the correct MRO order, otherwise
use the old -- incorrect -- order. See #428.
Return an `_Attributes`.
"""
cd = cls.__dict__
anns = _get_annotations(cls)
if these is not None:
ca_list = list(these.items())
elif auto_attribs is True:
ca_names = {
name
for name, attr in cd.items()
if isinstance(attr, _CountingAttr)
}
ca_list = []
annot_names = set()
for attr_name, type in anns.items():
if _is_class_var(type):
continue
annot_names.add(attr_name)
a = cd.get(attr_name, NOTHING)
if not isinstance(a, _CountingAttr):
a = attrib() if a is NOTHING else attrib(default=a)
ca_list.append((attr_name, a))
unannotated = ca_names - annot_names
if len(unannotated) > 0:
raise UnannotatedAttributeError(
"The following `attr.ib`s lack a type annotation: "
+ ", ".join(
sorted(unannotated, key=lambda n: cd.get(n).counter)
)
+ "."
)
else:
ca_list = sorted(
(
(name, attr)
for name, attr in cd.items()
if isinstance(attr, _CountingAttr)
),
key=lambda e: e[1].counter,
)
own_attrs = [
Attribute.from_counting_attr(
name=attr_name, ca=ca, type=anns.get(attr_name)
)
for attr_name, ca in ca_list
]
if collect_by_mro:
base_attrs, base_attr_map = _collect_base_attrs(
cls, {a.name for a in own_attrs}
)
else:
base_attrs, base_attr_map = _collect_base_attrs_broken(
cls, {a.name for a in own_attrs}
)
if kw_only:
own_attrs = [a.evolve(kw_only=True) for a in own_attrs]
base_attrs = [a.evolve(kw_only=True) for a in base_attrs]
attrs = base_attrs + own_attrs
# Mandatory vs non-mandatory attr order only matters when they are part of
# the __init__ signature and when they aren't kw_only (which are moved to
# the end and can be mandatory or non-mandatory in any order, as they will
# be specified as keyword args anyway). Check the order of those attrs:
had_default = False
for a in (a for a in attrs if a.init is not False and a.kw_only is False):
if had_default is True and a.default is NOTHING:
msg = f"No mandatory attributes allowed after an attribute with a default value or factory. Attribute in question: {a!r}"
raise ValueError(msg)
if had_default is False and a.default is not NOTHING:
had_default = True
if field_transformer is not None:
attrs = field_transformer(cls, attrs)
# Resolve default field alias after executing field_transformer.
# This allows field_transformer to differentiate between explicit vs
# default aliases and supply their own defaults.
attrs = [
a.evolve(alias=_default_init_alias_for(a.name)) if not a.alias else a
for a in attrs
]
# Create AttrsClass *after* applying the field_transformer since it may
# add or remove attributes!
attr_names = [a.name for a in attrs]
AttrsClass = _make_attr_tuple_class(cls.__name__, attr_names)
return _Attributes((AttrsClass(attrs), base_attrs, base_attr_map))
def _frozen_setattrs(self, name, value):
"""
Attached to frozen classes as __setattr__.
"""
if isinstance(self, BaseException) and name in (
"__cause__",
"__context__",
"__traceback__",
):
BaseException.__setattr__(self, name, value)
return
raise FrozenInstanceError()
def _frozen_delattrs(self, name):
"""
Attached to frozen classes as __delattr__.
"""
raise FrozenInstanceError()
class _ClassBuilder:
"""
Iteratively build *one* class.
"""
__slots__ = (
"_attr_names",
"_attrs",
"_base_attr_map",
"_base_names",
"_cache_hash",
"_cls",
"_cls_dict",
"_delete_attribs",
"_frozen",
"_has_pre_init",
"_pre_init_has_args",
"_has_post_init",
"_is_exc",
"_on_setattr",
"_slots",
"_weakref_slot",
"_wrote_own_setattr",
"_has_custom_setattr",
)
def __init__(
self,
cls,
these,
slots,
frozen,
weakref_slot,
getstate_setstate,
auto_attribs,
kw_only,
cache_hash,
is_exc,
collect_by_mro,
on_setattr,
has_custom_setattr,
field_transformer,
):
attrs, base_attrs, base_map = _transform_attrs(
cls,
these,
auto_attribs,
kw_only,
collect_by_mro,
field_transformer,
)
self._cls = cls
self._cls_dict = dict(cls.__dict__) if slots else {}
self._attrs = attrs
self._base_names = {a.name for a in base_attrs}
self._base_attr_map = base_map
self._attr_names = tuple(a.name for a in attrs)
self._slots = slots
self._frozen = frozen
self._weakref_slot = weakref_slot
self._cache_hash = cache_hash
self._has_pre_init = bool(getattr(cls, "__attrs_pre_init__", False))
self._pre_init_has_args = False
if self._has_pre_init:
# Check if the pre init method has more arguments than just `self`
# We want to pass arguments if pre init expects arguments
pre_init_func = cls.__attrs_pre_init__
pre_init_signature = inspect.signature(pre_init_func)
self._pre_init_has_args = len(pre_init_signature.parameters) > 1
self._has_post_init = bool(getattr(cls, "__attrs_post_init__", False))
self._delete_attribs = not bool(these)
self._is_exc = is_exc
self._on_setattr = on_setattr
self._has_custom_setattr = has_custom_setattr
self._wrote_own_setattr = False
self._cls_dict["__attrs_attrs__"] = self._attrs
if frozen:
self._cls_dict["__setattr__"] = _frozen_setattrs
self._cls_dict["__delattr__"] = _frozen_delattrs
self._wrote_own_setattr = True
elif on_setattr in (
_ng_default_on_setattr,
setters.validate,
setters.convert,
):
has_validator = has_converter = False
for a in attrs:
if a.validator is not None:
has_validator = True
if a.converter is not None:
has_converter = True
if has_validator and has_converter:
break
if (
(
on_setattr == _ng_default_on_setattr
and not (has_validator or has_converter)
)
or (on_setattr == setters.validate and not has_validator)
or (on_setattr == setters.convert and not has_converter)
):
# If class-level on_setattr is set to convert + validate, but
# there's no field to convert or validate, pretend like there's
# no on_setattr.
self._on_setattr = None
if getstate_setstate:
(
self._cls_dict["__getstate__"],
self._cls_dict["__setstate__"],
) = self._make_getstate_setstate()
def __repr__(self):
return f"<_ClassBuilder(cls={self._cls.__name__})>"
if PY310:
import abc
def build_class(self):
"""
Finalize class based on the accumulated configuration.
Builder cannot be used after calling this method.
"""
if self._slots is True:
return self._create_slots_class()
return self.abc.update_abstractmethods(
self._patch_original_class()
)
else:
def build_class(self):
"""
Finalize class based on the accumulated configuration.
Builder cannot be used after calling this method.
"""
if self._slots is True:
return self._create_slots_class()
return self._patch_original_class()
def _patch_original_class(self):
"""
Apply accumulated methods and return the class.
"""
cls = self._cls
base_names = self._base_names
# Clean class of attribute definitions (`attr.ib()`s).
if self._delete_attribs:
for name in self._attr_names:
if (
name not in base_names
and getattr(cls, name, _sentinel) is not _sentinel
):
# An AttributeError can happen if a base class defines a
# class variable and we want to set an attribute with the
# same name by using only a type annotation.
with contextlib.suppress(AttributeError):
delattr(cls, name)
# Attach our dunder methods.
for name, value in self._cls_dict.items():
setattr(cls, name, value)
# If we've inherited an attrs __setattr__ and don't write our own,
# reset it to object's.
if not self._wrote_own_setattr and getattr(
cls, "__attrs_own_setattr__", False
):
cls.__attrs_own_setattr__ = False
if not self._has_custom_setattr:
cls.__setattr__ = _obj_setattr
return cls
def _create_slots_class(self):
"""
Build and return a new class with a `__slots__` attribute.
"""
cd = {
k: v
for k, v in self._cls_dict.items()
if k not in (*tuple(self._attr_names), "__dict__", "__weakref__")
}
# If our class doesn't have its own implementation of __setattr__
# (either from the user or by us), check the bases, if one of them has
# an attrs-made __setattr__, that needs to be reset. We don't walk the
# MRO because we only care about our immediate base classes.
# XXX: This can be confused by subclassing a slotted attrs class with
# XXX: a non-attrs class and subclass the resulting class with an attrs
# XXX: class. See `test_slotted_confused` for details. For now that's
# XXX: OK with us.
if not self._wrote_own_setattr:
cd["__attrs_own_setattr__"] = False
if not self._has_custom_setattr:
for base_cls in self._cls.__bases__:
if base_cls.__dict__.get("__attrs_own_setattr__", False):
cd["__setattr__"] = _obj_setattr
break
# Traverse the MRO to collect existing slots
# and check for an existing __weakref__.
existing_slots = {}
weakref_inherited = False
for base_cls in self._cls.__mro__[1:-1]:
if base_cls.__dict__.get("__weakref__", None) is not None:
weakref_inherited = True
existing_slots.update(
{
name: getattr(base_cls, name)
for name in getattr(base_cls, "__slots__", [])
}
)
base_names = set(self._base_names)
names = self._attr_names
if (
self._weakref_slot
and "__weakref__" not in getattr(self._cls, "__slots__", ())
and "__weakref__" not in names
and not weakref_inherited
):
names += ("__weakref__",)
# We only add the names of attributes that aren't inherited.
# Setting __slots__ to inherited attributes wastes memory.
slot_names = [name for name in names if name not in base_names]
# There are slots for attributes from current class
# that are defined in parent classes.
# As their descriptors may be overridden by a child class,
# we collect them here and update the class dict
reused_slots = {
slot: slot_descriptor
for slot, slot_descriptor in existing_slots.items()
if slot in slot_names
}
slot_names = [name for name in slot_names if name not in reused_slots]
cd.update(reused_slots)
if self._cache_hash:
slot_names.append(_hash_cache_field)
cd["__slots__"] = tuple(slot_names)
cd["__qualname__"] = self._cls.__qualname__
# Create new class based on old class and our methods.
cls = type(self._cls)(self._cls.__name__, self._cls.__bases__, cd)
# The following is a fix for
# <https://github.com/python-attrs/attrs/issues/102>.
# If a method mentions `__class__` or uses the no-arg super(), the
# compiler will bake a reference to the class in the method itself
# as `method.__closure__`. Since we replace the class with a
# clone, we rewrite these references so it keeps working.
for item in cls.__dict__.values():
if isinstance(item, (classmethod, staticmethod)):
# Class- and staticmethods hide their functions inside.
# These might need to be rewritten as well.
closure_cells = getattr(item.__func__, "__closure__", None)
elif isinstance(item, property):
# Workaround for property `super()` shortcut (PY3-only).
# There is no universal way for other descriptors.
closure_cells = getattr(item.fget, "__closure__", None)
else:
closure_cells = getattr(item, "__closure__", None)
if not closure_cells: # Catch None or the empty list.
continue
for cell in closure_cells:
try:
match = cell.cell_contents is self._cls
except ValueError: # noqa: PERF203
# ValueError: Cell is empty
pass
else:
if match:
set_closure_cell(cell, cls)
return cls
def add_repr(self, ns):
self._cls_dict["__repr__"] = self._add_method_dunders(
_make_repr(self._attrs, ns, self._cls)
)
return self
def add_str(self):
repr = self._cls_dict.get("__repr__")
if repr is None:
msg = "__str__ can only be generated if a __repr__ exists."
raise ValueError(msg)
def __str__(self):
return self.__repr__()
self._cls_dict["__str__"] = self._add_method_dunders(__str__)
return self
def _make_getstate_setstate(self):
"""
Create custom __setstate__ and __getstate__ methods.
"""
# __weakref__ is not writable.
state_attr_names = tuple(
an for an in self._attr_names if an != "__weakref__"
)
def slots_getstate(self):
"""
Automatically created by attrs.
"""
return {name: getattr(self, name) for name in state_attr_names}
hash_caching_enabled = self._cache_hash
def slots_setstate(self, state):
"""
Automatically created by attrs.
"""
__bound_setattr = _obj_setattr.__get__(self)
if isinstance(state, tuple):
# Backward compatibility with attrs instances pickled with
# attrs versions before v22.2.0 which stored tuples.
for name, value in zip(state_attr_names, state):
__bound_setattr(name, value)
else:
for name in state_attr_names:
if name in state:
__bound_setattr(name, state[name])
# The hash code cache is not included when the object is
# serialized, but it still needs to be initialized to None to
# indicate that the first call to __hash__ should be a cache
# miss.
if hash_caching_enabled:
__bound_setattr(_hash_cache_field, None)
return slots_getstate, slots_setstate
def make_unhashable(self):
self._cls_dict["__hash__"] = None
return self
def add_hash(self):
self._cls_dict["__hash__"] = self._add_method_dunders(
_make_hash(
self._cls,
self._attrs,
frozen=self._frozen,
cache_hash=self._cache_hash,
)
)
return self
def add_init(self):
self._cls_dict["__init__"] = self._add_method_dunders(
_make_init(
self._cls,
self._attrs,
self._has_pre_init,
self._pre_init_has_args,
self._has_post_init,
self._frozen,
self._slots,