Fix bug with TypedDict for typing_extensions specifically (#120)

.github/workflows/build.yml

@@ -25,7 +25,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install tox tox-gh-actions poetry==1.2.2
+        pip install 'tox<5' tox-gh-actions 'poetry<1.5'
     - name: Test with tox
       run: tox
 

CHANGELOG.rst

@@ -1,6 +1,12 @@
 Changelog
 =========
 
+0.16.5 (2023-03-01)
+-------------------
+
+- Don't flag ``TypedDict`` from ``typing_extensions`` in Python versions
+  where ``typing`` has ``TypedDict`` itself.
+
 0.16.4 (2023-01-13)
 -------------------
 

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "slotscheck"
-version = "0.16.4"
+version = "0.16.5"
 description = "Ensure your __slots__ are working properly."
 authors = ["Arie Bovenberg <a.c.bovenberg@gmail.com>"]
 license = "MIT"
@@ -34,12 +34,11 @@ flake8 = "^5.0.4"
 isort = "^5.11.5"
 mypy = "^1.0"
 pytest = "^7.2.1"
-tox = "^3.27.1"
 black = "^23.1"
 pytest-cov = "^4.0.0"
 pytest-mock = "^3.6.1"
-types-dataclasses = "^0.6.6"
-# Not actually used, but a rare library whose __init__ is an extension.
+typing_extensions = ">=4.1,<5"
+# Only actually needed as an example library whose __init__ is an extension.
 pydantic = "1.9.2"
 
 [tool.poetry.scripts]

src/slotscheck/checks.py

@@ -1,12 +1,23 @@
 "Slots-related checks and inspection tools"
 import platform
 import sys
-from typing import Collection, Iterator, Optional
+from typing import Callable, Collection, Iterator, Optional
+
+from .common import either
+
+is_typeddict: Callable[[type], bool]
 
 try:
     from typing import is_typeddict
-except ImportError:  # pragma: no cover
-    from typing_extensions import is_typeddict
+
+    try:
+        from typing_extensions import is_typeddict as _is_typing_ext_typeddict
+    except ModuleNotFoundError:
+        pass
+    else:
+        is_typeddict = either(is_typeddict, _is_typing_ext_typeddict)
+except ModuleNotFoundError:  # pragma: no cover
+    from typing_extensions import is_typeddict as is_any_typeddict
 
 
 def slots(c: type) -> Optional[Collection[str]]:
@@ -26,7 +37,7 @@ def has_slots(c: type) -> bool:
     return (
         "__slots__" in c.__dict__
         or not (issubclass(c, BaseException) or is_pure_python(c))
-        or is_typeddict(c)
+        or is_any_typeddict(c)
     )
 
 

src/slotscheck/common.py

@@ -12,6 +12,7 @@
     Set,
     Tuple,
     TypeVar,
+    overload,
 )
 
 flatten = chain.from_iterable
@@ -69,6 +70,22 @@ def both(__a: Predicate[_T1], __b: Predicate[_T1]) -> Predicate[_T1]:
     return lambda x: __a(x) and __b(x)
 
 
+@overload
+def either(
+    __a: Callable[[_T1], bool], __b: Callable[[_T1], bool]
+) -> Callable[[_T1], bool]:
+    ...
+
+
+@overload
+def either(__a: Predicate[_T1], __b: Predicate[_T1]) -> Predicate[_T1]:
+    ...
+
+
+def either(__a: Any, __b: Any) -> Any:
+    return lambda x: __a(x) or __b(x)
+
+
 def map_optional(
     f: Callable[[_T1], Optional[_T2]], it: Iterable[_T1]
 ) -> Iterator[_T2]:

tests/src/test_checks.py

@@ -7,13 +7,14 @@
 from xml.etree.ElementTree import Element
 
 import pytest
+from typing_extensions import TypedDict as TypingExtensionsTypedDict
 
 from slotscheck.checks import has_slotless_base, has_slots, slots_overlap
 
 try:
     from typing import TypedDict
 except ImportError:
-    from typing_extensions import TypedDict
+    TypedDict = TypingExtensionsTypedDict
 
 
 class HasSlots:
@@ -73,6 +74,10 @@ class MyDict(TypedDict):
     foo: str
 
 
+class MyTypingExtensionsTypedDict(TypingExtensionsTypedDict):
+    bla: int
+
+
 class TestHasSlots:
     @pytest.mark.parametrize(
         "klass",
@@ -84,6 +89,9 @@ def test_not_purepython(self, klass):
     def test_typeddict(self):
         assert has_slots(MyDict)
 
+    def test_typing_extensions_typeddict(self):
+        assert has_slots(MyTypingExtensionsTypedDict)
+
     @pytest.mark.parametrize(
         "klass",
         [