Jan 16, 2026 · Feb 2, 2026 · Feb 2, 2026 · Feb 3, 2026 · Feb 2, 2026 · Feb 2, 2026
diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py
 import sys
 import copy
 import types
 import inspect
 import keyword
 import itertools
 import annotationlib
 # See https://bugs.python.org/issue32929#msg312829 for an if-statement
 # version of this table.

 class AutoDocstring:
    """A non-data descriptor to autogenerate class docstring
    from the signature of its __init__ method.
    """

    def __get__(self, _obj, cls):
        # TODO: Make this top-level lazy import once PEP810 lands
        import inspect

        try:
            # In some cases fetching a signature is not possible.
            # But, we surely should not fail in this case.
            text_sig = str(inspect.signature(
                 cls,
                 annotation_format=annotationlib.Format.FORWARDREF,
            )).replace(' -> None', '')
        except (TypeError, ValueError):
            text_sig = ''

        doc = cls.__name__ + text_sig
        setattr(cls, '__doc__', doc)
        return doc


 def _process_class(cls, init, repr, eq, order, unsafe_hash, frozen,
                   match_args, kw_only, slots, weakref_slot):
    if hash_action:
        cls.__hash__ = hash_action(cls, field_list, func_builder)

    # Generate the methods and add them to the class.  This needs to be done
    # before the __doc__ logic below, since inspect will look at the __init__
    # signature.
    # Generate the methods and add them to the class.
    func_builder.add_fns_to_class(cls)

    if not getattr(cls, '__doc__'):
        # Create a class doc-string.
        try:
            # In some cases fetching a signature is not possible.
            # But, we surely should not fail in this case.
            text_sig = str(inspect.signature(
                cls,
                annotation_format=annotationlib.Format.FORWARDREF,
            )).replace(' -> None', '')
        except (TypeError, ValueError):
            text_sig = ''
        cls.__doc__ = (cls.__name__ + text_sig)
        # Create a class doc-string lazily via descriptor protocol
        # to avoid importing `inspect` module.
        cls.__doc__ = AutoDocstring()

    if match_args:
        # I could probably compute this once.
    # make an update, since all closures for a class will share a
    # given cell.
    for member in newcls.__dict__.values():

        # If this is a wrapped function, unwrap it.
        member = inspect.unwrap(member)
        if not isinstance(member, type) and hasattr(member, '__wrapped__'):
            # TODO: Make this top-level lazy import once PEP810 lands
            import inspect
            member = inspect.unwrap(member)

        if isinstance(member, types.FunctionType):
            if _update_func_cell_for__class__(member, cls, newcls):
diff --git a/Lib/inspect.py b/Lib/inspect.py
 from collections import namedtuple, OrderedDict
 from weakref import ref as make_weakref

 # Create constants for the compiler flags in Include/code.h
 # Create constants for the compiler flags in Include/cpython/code.h
 # We try to get them from dis to avoid duplication
 mod_dict = globals()
 for k, v in dis.COMPILER_FLAG_NAMES.items():
diff --git a/Lib/test/test_dataclasses/__init__.py b/Lib/test/test_dataclasses/__init__.py

        self.assertDocStrEqual(C.__doc__, "C()")

    def test_docstring_slotted(self):
        @dataclass(slots=True)
        class C:
            x: int

        self.assertDocStrEqual(C.__doc__, "C(x:int)")

    def test_docstring_one_field(self):
        @dataclass
        class C:
Original file line number	Diff line number	Diff line change
Expand Up		@@ -2,7 +2,6 @@
		import sys
		import copy
		import types
		import inspect
		import keyword
		import itertools
		import annotationlib
Expand DownExpand Up		@@ -982,6 +981,29 @@ def _hash_exception(cls, fields, func_builder):
		# See https://bugs.python.org/issue32929#msg312829 for an if-statement
		# version of this table.

		class AutoDocstring:
Copy link Contributor sergey-miryanovFeb 3, 2026 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. I'm not sure we should add a new top-level entity here (despite it seems useful).
		"""A non-data descriptor to autogenerate class docstring
		from the signature of its __init__ method.
		"""

		def __get__(self, _obj, cls):
		# TODO: Make this top-level lazy import once PEP810 lands
		import inspect

		try:
		# In some cases fetching a signature is not possible.
		# But, we surely should not fail in this case.
		text_sig = str(inspect.signature(
		cls,
		annotation_format=annotationlib.Format.FORWARDREF,
		)).replace(' -> None', '')
		except (TypeError, ValueError):
		text_sig = ''

		doc = cls.__name__ + text_sig
		setattr(cls, '__doc__', doc)
		return doc


		def _process_class(cls, init, repr, eq, order, unsafe_hash, frozen,
		match_args, kw_only, slots, weakref_slot):
Expand DownExpand Up		@@ -1209,23 +1231,13 @@ def _process_class(cls, init, repr, eq, order, unsafe_hash, frozen,
		if hash_action:
		cls.__hash__ = hash_action(cls, field_list, func_builder)

		# Generate the methods and add them to the class. This needs to be done
		# before the __doc__ logic below, since inspect will look at the __init__
		# signature.
		# Generate the methods and add them to the class.
		func_builder.add_fns_to_class(cls)

		if not getattr(cls, '__doc__'):
		# Create a class doc-string.
		try:
		# In some cases fetching a signature is not possible.
		# But, we surely should not fail in this case.
		text_sig = str(inspect.signature(
		cls,
		annotation_format=annotationlib.Format.FORWARDREF,
		)).replace(' -> None', '')
		except (TypeError, ValueError):
		text_sig = ''
		cls.__doc__ = (cls.__name__ + text_sig)
		# Create a class doc-string lazily via descriptor protocol
		# to avoid importing `inspect` module.
		cls.__doc__ = AutoDocstring()

		if match_args:
		# I could probably compute this once.
Expand DownExpand Up		@@ -1377,8 +1389,12 @@ def _add_slots(cls, is_frozen, weakref_slot, defined_fields):
		# make an update, since all closures for a class will share a
		# given cell.
		for member in newcls.__dict__.values():

		# If this is a wrapped function, unwrap it.
		member = inspect.unwrap(member)
		if not isinstance(member, type) and hasattr(member, '__wrapped__'):
Copy link ContributorAuthor danielhollasFeb 2, 2026 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. This check was copied from the while loop in`inspect.unwrap`
		# TODO: Make this top-level lazy import once PEP810 lands
Copy link Member StanFromIrelandFeb 2, 2026 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. PEP 810is landing in 3.15, there is no point in adding an intermediate stage here, we can wait a few weeks. aisk reacted with thumbs up emoji
		import inspect
		member = inspect.unwrap(member)

		if isinstance(member, types.FunctionType):
		if _update_func_cell_for__class__(member, cls, newcls):
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -165,7 +165,7 @@
		from collections import namedtuple, OrderedDict
		from weakref import ref as make_weakref

		# Create constants for the compiler flags in Include/code.h
		# Create constants for the compiler flags in Include/cpython/code.h
		# We try to get them from dis to avoid duplication
		mod_dict = globals()
		for k, v in dis.COMPILER_FLAG_NAMES.items():
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -2295,6 +2295,13 @@ class C:

		self.assertDocStrEqual(C.__doc__, "C()")

		def test_docstring_slotted(self):
		@dataclass(slots=True)
		class C:
		x: int

		self.assertDocStrEqual(C.__doc__, "C(x:int)")

		def test_docstring_one_field(self):
		@dataclass
		class C:
Expand Down