Merge pull request #90 from oxan/pep695

PEP 695 support

rest_framework_dataclasses/field_utils.py

@@ -75,7 +75,7 @@ def get_type_info(tp: type) -> TypeInfo:
  tp = typing_utils.get_iterable_element_type(tp)
 
  if typing_utils.is_type_variable(tp):
- tp = typing_utils.get_variable_type_substitute(tp)
+ tp = typing_utils.get_type_variable_substitution(tp)
 
  return TypeInfo(is_many, is_mapping, is_final, is_nullable, tp, cp)
 

rest_framework_dataclasses/typing_utils.py

@@ -56,8 +56,10 @@ def get_resolved_type_hints(tp: type) -> typing.Dict[str, type]:
  Resolving the type hints means converting any stringified type hint into an actual type object. These can come from
  either forward references (PEP 484), or postponed evaluation (PEP 563).
  """
- # typing.get_type_hints() does the heavy lifting for us, except when using PEP 585 generic types that contain a
- # stringified type hint (see https://bugs.python.org/issue41370)
+ # typing.get_type_hints() does the heavy lifting for us, except:
+ # - when using PEP 585 generic types that contain a stringified type hint, on Python 3.9 and 3.10. See
+ # https://bugs.python.org/issue41370. Only references to objects in the global namespace are supported here.
+ # - when using PEP 695 type aliases
  def _resolve_type(context_type: type, resolve_type: typing.Union[str, type]) -> type:
  if isinstance(resolve_type, str):
  globalsns = sys.modules[context_type.__module__].__dict__
@@ -66,12 +68,14 @@ def _resolve_type(context_type: type, resolve_type: typing.Union[str, type]) ->
  return _resolve_type_hint(context_type, resolve_type)
 
  def _resolve_type_hint(context_type: type, resolve_type: type) -> type:
- if not hasattr(types, 'GenericAlias') or not isinstance(resolve_type, types.GenericAlias):
+ if hasattr(types, 'GenericAlias') and isinstance(resolve_type, types.GenericAlias):
+ args = tuple(_resolve_type(context_type, arg) for arg in resolve_type.__args__)
+ return typing.cast(type, types.GenericAlias(resolve_type.__origin__, args))
+ elif hasattr(typing, 'TypeAliasType') and isinstance(resolve_type, typing.TypeAliasType):
+ return _resolve_type_hint(context_type, resolve_type.__value__)
+ else:
  return resolve_type
 
- args = tuple(_resolve_type(context_type, arg) for arg in resolve_type.__args__)
- return typing.cast(type, types.GenericAlias(resolve_type.__origin__, args))
-
  return {k: _resolve_type_hint(tp, v) for k, v in typing.get_type_hints(tp).items()}
 
 
@@ -284,7 +288,7 @@ def is_type_variable(tp: type) -> bool:
  return isinstance(tp, typing.TypeVar)
 
 
-def get_variable_type_substitute(tp: type) -> type:
+def get_type_variable_substitution(tp: type) -> type:
  """
  Get the substitute for a variable type.
  """

tests/__init__.py

@@ -0,0 +1,21 @@
+import unittest
+import sys
+
+
+def load_tests(loader: unittest.TestLoader, tests, pattern):
+ # Manually load tests to avoid loading tests with syntax that's incompatible with the current Python version
+ for module in (
+ 'test_field_generation',
+ 'test_field_utils',
+ 'test_fields',
+ 'test_functional',
+ 'test_issues',
+ 'test_serializers',
+ 'test_typing_utils',
+ ):
+ tests.addTests(loader.loadTestsFromName('tests.' + module))
+
+ if sys.version_info >= (3, 12, 0):
+ tests.addTests(loader.loadTestsFromName('tests.test_py312'))
+
+ return tests

tests/test_py312.py

@@ -0,0 +1,35 @@
+import typing
+import unittest
+import sys
+
+from rest_framework_dataclasses import typing_utils
+
+
+@unittest.skipIf(sys.version_info < (3, 12, 0), 'Python 3.12 required')
+class Python312Test(unittest.TestCase):
+ def test_resolve_pep695(self):
+ type Str = str
+ type StrList = list[str]
+ type GenericList[T] = list[T]
+
+ class Hinted:
+ a: Str
+ b: StrList
+ c: GenericList
+
+ hints = typing_utils.get_resolved_type_hints(Hinted)
+ self.assertEqual(hints['a'], str)
+ self.assertEqual(hints['b'], list[str])
+ self.assertEqual(typing.get_origin(hints['c']), list)
+
+ def test_typevar_pep695(self):
+ type GenericList[T: str] = list[T]
+ def fn() -> GenericList:
+ pass
+
+ tp = typing_utils.get_resolved_type_hints(fn)['return']
+
+ self.assertTrue(typing_utils.is_iterable_type(tp))
+ element_type = typing_utils.get_iterable_element_type(tp)
+ self.assertTrue(typing_utils.is_type_variable(element_type))
+ self.assertEqual(typing_utils.get_type_variable_substitution(element_type), str)

tests/test_typing_utils.py

@@ -1,16 +1,51 @@
+import types as types_module
 import typing
 import unittest
 import sys
 
 from rest_framework_dataclasses import types, typing_utils
 
 
+class GlobalType:
+ pass
+
+
 class TypingTest(unittest.TestCase):
  def assertAnyTypeEquivalent(self, tp: type):
  # In some cases we accept either typing.Any (used by Python 3.9+) or an unconstrained typevar (used by Python
  # 3.7 and 3.8). It's essentially the same, and we strip the typevar before usage anyway.
  self.assertTrue(tp is typing.Any or (isinstance(tp, typing.TypeVar) and len(tp.__constraints__) == 0))
 
+ def test_resolve(self):
+ class Hinted:
+ a: str
+ b: 'str'
+
+ hints = typing_utils.get_resolved_type_hints(Hinted)
+ self.assertEqual(hints['a'], str)
+ self.assertEqual(hints['b'], str)
+
+ @unittest.skipIf(sys.version_info < (3, 9, 0), 'Python 3.9 required')
+ def test_resolve_pep585(self):
+ # Pre-Python 3.11 only references to the global namespace are supported
+ class Hinted:
+ a: list[GlobalType]
+ b: list['GlobalType']
+
+ hints = typing_utils.get_resolved_type_hints(Hinted)
+ self.assertEqual(hints['a'], types_module.GenericAlias(list, (GlobalType, )))
+ self.assertEqual(hints['b'], types_module.GenericAlias(list, (GlobalType, )))
+
+ @unittest.skipIf(sys.version_info < (3, 11, 0), 'Python 3.11 required')
+ def test_resolve_pep585_full(self):
+ class Hinted:
+ a: list[str]
+ b: list['str']
+
+ hints = typing_utils.get_resolved_type_hints(Hinted)
+ self.assertEqual(hints['a'], types_module.GenericAlias(list, (str, )))
+ self.assertEqual(hints['b'], types_module.GenericAlias(list, (str, )))
+
  def test_iterable(self):
  self.assertTrue(typing_utils.is_iterable_type(typing.Iterable[str]))
  self.assertTrue(typing_utils.is_iterable_type(typing.Collection[str]))
@@ -169,6 +204,6 @@ def test_variable_type(self):
  self.assertFalse(typing_utils.is_type_variable(int))
  self.assertFalse(typing_utils.is_type_variable(typing.List))
 
- self.assertEqual(typing_utils.get_variable_type_substitute(T), typing.Any)
- self.assertEqual(typing_utils.get_variable_type_substitute(U), typing.Union[int, str])
- self.assertEqual(typing_utils.get_variable_type_substitute(V), Exception)
+ self.assertEqual(typing_utils.get_type_variable_substitution(T), typing.Any)
+ self.assertEqual(typing_utils.get_type_variable_substitution(U), typing.Union[int, str])
+ self.assertEqual(typing_utils.get_type_variable_substitution(V), Exception)