diff options
Diffstat (limited to 'Lib/dataclasses.py')
| -rw-r--r-- | Lib/dataclasses.py | 54 |
1 files changed, 37 insertions, 17 deletions
diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py index f5cb97e..bdda7cc 100644 --- a/Lib/dataclasses.py +++ b/Lib/dataclasses.py @@ -283,11 +283,12 @@ class Field: 'compare', 'metadata', 'kw_only', + 'doc', '_field_type', # Private: not to be used by user code. ) def __init__(self, default, default_factory, init, repr, hash, compare, - metadata, kw_only): + metadata, kw_only, doc): self.name = None self.type = None self.default = default @@ -300,6 +301,7 @@ class Field: if metadata is None else types.MappingProxyType(metadata)) self.kw_only = kw_only + self.doc = doc self._field_type = None @recursive_repr() @@ -315,6 +317,7 @@ class Field: f'compare={self.compare!r},' f'metadata={self.metadata!r},' f'kw_only={self.kw_only!r},' + f'doc={self.doc!r},' f'_field_type={self._field_type}' ')') @@ -382,7 +385,7 @@ class _DataclassParams: # so that a type checker can be told (via overloads) that this is a # function whose type depends on its parameters. def field(*, default=MISSING, default_factory=MISSING, init=True, repr=True, - hash=None, compare=True, metadata=None, kw_only=MISSING): + hash=None, compare=True, metadata=None, kw_only=MISSING, doc=None): """Return an object to identify dataclass fields. default is the default value of the field. default_factory is a @@ -394,7 +397,7 @@ def field(*, default=MISSING, default_factory=MISSING, init=True, repr=True, comparison functions. metadata, if specified, must be a mapping which is stored but not otherwise examined by dataclass. If kw_only is true, the field will become a keyword-only parameter to - __init__(). + __init__(). doc is an optional docstring for this field. It is an error to specify both default and default_factory. """ @@ -402,7 +405,7 @@ def field(*, default=MISSING, default_factory=MISSING, init=True, repr=True, if default is not MISSING and default_factory is not MISSING: raise ValueError('cannot specify both default and default_factory') return Field(default, default_factory, init, repr, hash, compare, - metadata, kw_only) + metadata, kw_only, doc) def _fields_in_init_order(fields): @@ -1174,7 +1177,7 @@ def _process_class(cls, init, repr, eq, order, unsafe_hash, frozen, if weakref_slot and not slots: raise TypeError('weakref_slot is True but slots is False') if slots: - cls = _add_slots(cls, frozen, weakref_slot) + cls = _add_slots(cls, frozen, weakref_slot, fields) abc.update_abstractmethods(cls) @@ -1239,7 +1242,32 @@ def _update_func_cell_for__class__(f, oldcls, newcls): return False -def _add_slots(cls, is_frozen, weakref_slot): +def _create_slots(defined_fields, inherited_slots, field_names, weakref_slot): + # The slots for our class. Remove slots from our base classes. Add + # '__weakref__' if weakref_slot was given, unless it is already present. + seen_docs = False + slots = {} + for slot in itertools.filterfalse( + inherited_slots.__contains__, + itertools.chain( + # gh-93521: '__weakref__' also needs to be filtered out if + # already present in inherited_slots + field_names, ('__weakref__',) if weakref_slot else () + ) + ): + doc = getattr(defined_fields.get(slot), 'doc', None) + if doc is not None: + seen_docs = True + slots.update({slot: doc}) + + # We only return dict if there's at least one doc member, + # otherwise we return tuple, which is the old default format. + if seen_docs: + return slots + return tuple(slots) + + +def _add_slots(cls, is_frozen, weakref_slot, defined_fields): # Need to create a new class, since we can't set __slots__ after a # class has been created, and the @dataclass decorator is called # after the class is created. @@ -1255,17 +1283,9 @@ def _add_slots(cls, is_frozen, weakref_slot): inherited_slots = set( itertools.chain.from_iterable(map(_get_slots, cls.__mro__[1:-1])) ) - # The slots for our class. Remove slots from our base classes. Add - # '__weakref__' if weakref_slot was given, unless it is already present. - cls_dict["__slots__"] = tuple( - itertools.filterfalse( - inherited_slots.__contains__, - itertools.chain( - # gh-93521: '__weakref__' also needs to be filtered out if - # already present in inherited_slots - field_names, ('__weakref__',) if weakref_slot else () - ) - ), + + cls_dict["__slots__"] = _create_slots( + defined_fields, inherited_slots, field_names, weakref_slot, ) for field_name in field_names: |