https://github.com/python/cpython/commit/727cdcba8ea01a1f317f560bc9fc8fbd2912011d commit: 727cdcba8ea01a1f317f560bc9fc8fbd2912011d branch: 3.14 author: Jelle Zijlstra <[email protected]> committer: JelleZijlstra <[email protected]> date: 2025-11-10T07:14:32-08:00 summary:
[3.14] gh-137530: generate an __annotate__ function for dataclasses __init__ (GH-137711) (#141352) (cherry picked from commit 12837c63635559873a5abddf511d38456d69617b) Co-authored-by: David Ellis <[email protected]> files: A Misc/NEWS.d/next/Library/2025-10-21-15-54-13.gh-issue-137530.ZyIVUH.rst M Lib/dataclasses.py M Lib/test/test_dataclasses/__init__.py diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py index d29f1615f276d2..fb7e1701cce0a4 100644 --- a/Lib/dataclasses.py +++ b/Lib/dataclasses.py @@ -441,9 +441,11 @@ def __init__(self, globals): self.locals = {} self.overwrite_errors = {} self.unconditional_adds = {} + self.method_annotations = {} def add_fn(self, name, args, body, *, locals=None, return_type=MISSING, - overwrite_error=False, unconditional_add=False, decorator=None): + overwrite_error=False, unconditional_add=False, decorator=None, + annotation_fields=None): if locals is not None: self.locals.update(locals) @@ -464,16 +466,14 @@ def add_fn(self, name, args, body, *, locals=None, return_type=MISSING, self.names.append(name) - if return_type is not MISSING: - self.locals[f'__dataclass_{name}_return_type__'] = return_type - return_annotation = f'->__dataclass_{name}_return_type__' - else: - return_annotation = '' + if annotation_fields is not None: + self.method_annotations[name] = (annotation_fields, return_type) + args = ','.join(args) body = '\n'.join(body) # Compute the text of the entire function, add it to the text we're generating. - self.src.append(f'{f' {decorator}\n' if decorator else ''} def {name}({args}){return_annotation}:\n{body}') + self.src.append(f'{f' {decorator}\n' if decorator else ''} def {name}({args}):\n{body}') def add_fns_to_class(self, cls): # The source to all of the functions we're generating. @@ -509,6 +509,15 @@ def add_fns_to_class(self, cls): # Now that we've generated the functions, assign them into cls. for name, fn in zip(self.names, fns): fn.__qualname__ = f"{cls.__qualname__}.{fn.__name__}" + + try: + annotation_fields, return_type = self.method_annotations[name] + except KeyError: + pass + else: + annotate_fn = _make_annotate_function(cls, name, annotation_fields, return_type) + fn.__annotate__ = annotate_fn + if self.unconditional_adds.get(name, False): setattr(cls, name, fn) else: @@ -524,6 +533,44 @@ def add_fns_to_class(self, cls): raise TypeError(error_msg) +def _make_annotate_function(__class__, method_name, annotation_fields, return_type): + # Create an __annotate__ function for a dataclass + # Try to return annotations in the same format as they would be + # from a regular __init__ function + + def __annotate__(format, /): + Format = annotationlib.Format + match format: + case Format.VALUE | Format.FORWARDREF | Format.STRING: + cls_annotations = {} + for base in reversed(__class__.__mro__): + cls_annotations.update( + annotationlib.get_annotations(base, format=format) + ) + + new_annotations = {} + for k in annotation_fields: + new_annotations[k] = cls_annotations[k] + + if return_type is not MISSING: + if format == Format.STRING: + new_annotations["return"] = annotationlib.type_repr(return_type) + else: + new_annotations["return"] = return_type + + return new_annotations + + case _: + raise NotImplementedError(format) + + # This is a flag for _add_slots to know it needs to regenerate this method + # In order to remove references to the original class when it is replaced + __annotate__.__generated_by_dataclasses__ = True + __annotate__.__qualname__ = f"{__class__.__qualname__}.{method_name}.__annotate__" + + return __annotate__ + + def _field_assign(frozen, name, value, self_name): # If we're a frozen class, then assign to our fields in __init__ # via object.__setattr__. Otherwise, just use a simple @@ -612,7 +659,7 @@ def _init_param(f): elif f.default_factory is not MISSING: # There's a factory function. Set a marker. default = '=__dataclass_HAS_DEFAULT_FACTORY__' - return f'{f.name}:__dataclass_type_{f.name}__{default}' + return f'{f.name}{default}' def _init_fn(fields, std_fields, kw_only_fields, frozen, has_post_init, @@ -635,11 +682,10 @@ def _init_fn(fields, std_fields, kw_only_fields, frozen, has_post_init, raise TypeError(f'non-default argument {f.name!r} ' f'follows default argument {seen_default.name!r}') - locals = {**{f'__dataclass_type_{f.name}__': f.type for f in fields}, - **{'__dataclass_HAS_DEFAULT_FACTORY__': _HAS_DEFAULT_FACTORY, - '__dataclass_builtins_object__': object, - } - } + annotation_fields = [f.name for f in fields if f.init] + + locals = {'__dataclass_HAS_DEFAULT_FACTORY__': _HAS_DEFAULT_FACTORY, + '__dataclass_builtins_object__': object} body_lines = [] for f in fields: @@ -670,7 +716,8 @@ def _init_fn(fields, std_fields, kw_only_fields, frozen, has_post_init, [self_name] + _init_params, body_lines, locals=locals, - return_type=None) + return_type=None, + annotation_fields=annotation_fields) def _frozen_get_del_attr(cls, fields, func_builder): @@ -1336,6 +1383,25 @@ def _add_slots(cls, is_frozen, weakref_slot, defined_fields): or _update_func_cell_for__class__(member.fdel, cls, newcls)): break + # Get new annotations to remove references to the original class + # in forward references + newcls_ann = annotationlib.get_annotations( + newcls, format=annotationlib.Format.FORWARDREF) + + # Fix references in dataclass Fields + for f in getattr(newcls, _FIELDS).values(): + try: + ann = newcls_ann[f.name] + except KeyError: + pass + else: + f.type = ann + + # Fix the class reference in the __annotate__ method + init_annotate = newcls.__init__.__annotate__ + if getattr(init_annotate, "__generated_by_dataclasses__", False): + _update_func_cell_for__class__(init_annotate, cls, newcls) + return newcls diff --git a/Lib/test/test_dataclasses/__init__.py b/Lib/test/test_dataclasses/__init__.py index 6bf5e5b3e5554b..513dd78c4381b4 100644 --- a/Lib/test/test_dataclasses/__init__.py +++ b/Lib/test/test_dataclasses/__init__.py @@ -2471,6 +2471,135 @@ def __init__(self, a): self.assertEqual(D(5).a, 10) +class TestInitAnnotate(unittest.TestCase): + # Tests for the generated __annotate__ function for __init__ + # See: https://github.com/python/cpython/issues/137530 + + def test_annotate_function(self): + # No forward references + @dataclass + class A: + a: int + + value_annos = annotationlib.get_annotations(A.__init__, format=annotationlib.Format.VALUE) + forwardref_annos = annotationlib.get_annotations(A.__init__, format=annotationlib.Format.FORWARDREF) + string_annos = annotationlib.get_annotations(A.__init__, format=annotationlib.Format.STRING) + + self.assertEqual(value_annos, {'a': int, 'return': None}) + self.assertEqual(forwardref_annos, {'a': int, 'return': None}) + self.assertEqual(string_annos, {'a': 'int', 'return': 'None'}) + + self.assertTrue(getattr(A.__init__.__annotate__, "__generated_by_dataclasses__")) + + def test_annotate_function_forwardref(self): + # With forward references + @dataclass + class B: + b: undefined + + # VALUE annotations should raise while unresolvable + with self.assertRaises(NameError): + _ = annotationlib.get_annotations(B.__init__, format=annotationlib.Format.VALUE) + + forwardref_annos = annotationlib.get_annotations(B.__init__, format=annotationlib.Format.FORWARDREF) + string_annos = annotationlib.get_annotations(B.__init__, format=annotationlib.Format.STRING) + + self.assertEqual(forwardref_annos, {'b': support.EqualToForwardRef('undefined', owner=B, is_class=True), 'return': None}) + self.assertEqual(string_annos, {'b': 'undefined', 'return': 'None'}) + + # Now VALUE and FORWARDREF should resolve, STRING should be unchanged + undefined = int + + value_annos = annotationlib.get_annotations(B.__init__, format=annotationlib.Format.VALUE) + forwardref_annos = annotationlib.get_annotations(B.__init__, format=annotationlib.Format.FORWARDREF) + string_annos = annotationlib.get_annotations(B.__init__, format=annotationlib.Format.STRING) + + self.assertEqual(value_annos, {'b': int, 'return': None}) + self.assertEqual(forwardref_annos, {'b': int, 'return': None}) + self.assertEqual(string_annos, {'b': 'undefined', 'return': 'None'}) + + def test_annotate_function_init_false(self): + # Check `init=False` attributes don't get into the annotations of the __init__ function + @dataclass + class C: + c: str = field(init=False) + + self.assertEqual(annotationlib.get_annotations(C.__init__), {'return': None}) + + def test_annotate_function_contains_forwardref(self): + # Check string annotations on objects containing a ForwardRef + @dataclass + class D: + d: list[undefined] + + with self.assertRaises(NameError): + annotationlib.get_annotations(D.__init__) + + self.assertEqual( + annotationlib.get_annotations(D.__init__, format=annotationlib.Format.FORWARDREF), + {"d": list[support.EqualToForwardRef("undefined", is_class=True, owner=D)], "return": None} + ) + + self.assertEqual( + annotationlib.get_annotations(D.__init__, format=annotationlib.Format.STRING), + {"d": "list[undefined]", "return": "None"} + ) + + # Now test when it is defined + undefined = str + + # VALUE should now resolve + self.assertEqual( + annotationlib.get_annotations(D.__init__), + {"d": list[str], "return": None} + ) + + self.assertEqual( + annotationlib.get_annotations(D.__init__, format=annotationlib.Format.FORWARDREF), + {"d": list[str], "return": None} + ) + + self.assertEqual( + annotationlib.get_annotations(D.__init__, format=annotationlib.Format.STRING), + {"d": "list[undefined]", "return": "None"} + ) + + def test_annotate_function_not_replaced(self): + # Check that __annotate__ is not replaced on non-generated __init__ functions + @dataclass(slots=True) + class E: + x: str + def __init__(self, x: int) -> None: + self.x = x + + self.assertEqual( + annotationlib.get_annotations(E.__init__), {"x": int, "return": None} + ) + + self.assertFalse(hasattr(E.__init__.__annotate__, "__generated_by_dataclasses__")) + + def test_init_false_forwardref(self): + # Test forward references in fields not required for __init__ annotations. + + # At the moment this raises a NameError for VALUE annotations even though the + # undefined annotation is not required for the __init__ annotations. + # Ideally this will be fixed but currently there is no good way to resolve this + + @dataclass + class F: + not_in_init: list[undefined] = field(init=False, default=None) + in_init: int + + annos = annotationlib.get_annotations(F.__init__, format=annotationlib.Format.FORWARDREF) + self.assertEqual( + annos, + {"in_init": int, "return": None}, + ) + + with self.assertRaises(NameError): + annos = annotationlib.get_annotations(F.__init__) # NameError on not_in_init + + class TestRepr(unittest.TestCase): def test_repr(self): @dataclass @@ -3831,7 +3960,15 @@ def method(self) -> int: return SlotsTest - for make in (make_simple, make_with_annotations, make_with_annotations_and_method): + def make_with_forwardref(): + @dataclass(slots=True) + class SlotsTest: + x: undefined + y: list[undefined] + + return SlotsTest + + for make in (make_simple, make_with_annotations, make_with_annotations_and_method, make_with_forwardref): with self.subTest(make=make): C = make() support.gc_collect() diff --git a/Misc/NEWS.d/next/Library/2025-10-21-15-54-13.gh-issue-137530.ZyIVUH.rst b/Misc/NEWS.d/next/Library/2025-10-21-15-54-13.gh-issue-137530.ZyIVUH.rst new file mode 100644 index 00000000000000..4ff55b41dea96e --- /dev/null +++ b/Misc/NEWS.d/next/Library/2025-10-21-15-54-13.gh-issue-137530.ZyIVUH.rst @@ -0,0 +1 @@ +:mod:`dataclasses` Fix annotations for generated ``__init__`` methods by replacing the annotations that were in-line in the generated source code with ``__annotate__`` functions attached to the methods. _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
