Merge branch 'main' into add-mypy-const

.github/workflows/main.yml

@@ -27,7 +27,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-      - uses: actions/setup-python@v3
+      - uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
 
@@ -54,7 +54,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-      - uses: actions/setup-python@v3
+      - uses: actions/setup-python@v4
         with:
           # Use latest Python, so it understands all syntax.
           python-version: ${{env.PYTHON_LATEST}}
@@ -86,7 +86,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-      - uses: actions/setup-python@v3
+      - uses: actions/setup-python@v4
         with:
           python-version: ${{env.PYTHON_LATEST}}
 
@@ -107,7 +107,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-      - uses: actions/setup-python@v3
+      - uses: actions/setup-python@v4
         with:
           python-version: ${{env.PYTHON_LATEST}}
       - run: python -m pip install -e .[dev]

changelog.d/1001.change.rst

@@ -0,0 +1,3 @@
+On Python 3.10 and later, call `abc.update_abstractmethods() <https://docs.pytho.
+org/3.10/library/abc.html#abc.update_abstractmethods>`_ on dict classes after creation.
+This improves the detection of abstractness.

changelog.d/997.change.rst

@@ -0,0 +1,2 @@
+``attrs.has()`` is now a ``TypeGuard`` for ``AttrsInstance``.
+That means that type checkers know a class is an instance of an ``attrs`` class if you check it using ``attrs.has()`` (or ``attr.has()``) first.

setup.py

@@ -143,5 +143,4 @@ def find_meta(meta):
         install_requires=INSTALL_REQUIRES,
         extras_require=EXTRAS_REQUIRE,
         include_package_data=True,
-        options={"bdist_wheel": {"universal": "1"}},
     )

src/attr/__init__.pyi

@@ -28,6 +28,11 @@ from ._typing_compat import AttrsInstance_
 
 AttrsInstance = AttrsInstance_
 
+if sys.version_info >= (3, 10):
+    from typing import TypeGuard
+else:
+    from typing_extensions import TypeGuard
+
 __version__: str
 __version_info__: VersionInfo
 __title__: str
@@ -467,7 +472,7 @@ def astuple(
     tuple_factory: Type[Sequence[Any]] = ...,
     retain_collection_types: bool = ...,
 ) -> Tuple[Any, ...]: ...
-def has(cls: type) -> bool: ...
+def has(cls: type) -> TypeGuard[Type[AttrsInstance]]: ...
 def assoc(inst: _T, **changes: Any) -> _T: ...
 def evolve(inst: _T, **changes: Any) -> _T: ...
 

src/attr/_make.py

@@ -717,15 +717,33 @@ def __init__(
     def __repr__(self):
         return f"<_ClassBuilder(cls={self._cls.__name__})>"
 
-    def build_class(self):
-        """
-        Finalize class based on the accumulated configuration.
+    if PY310:
+        import abc
+
+        def build_class(self):
+            """
+            Finalize class based on the accumulated configuration.
+
+            Builder cannot be used after calling this method.
+            """
+            if self._slots is True:
+                return self._create_slots_class()
+
+            return self.abc.update_abstractmethods(
+                self._patch_original_class()
+            )
+
+    else:
+
+        def build_class(self):
+            """
+            Finalize class based on the accumulated configuration.
+
+            Builder cannot be used after calling this method.
+            """
+            if self._slots is True:
+                return self._create_slots_class()
 
-        Builder cannot be used after calling this method.
-        """
-        if self._slots is True:
-            return self._create_slots_class()
-        else:
             return self._patch_original_class()
 
     def _patch_original_class(self):

tests/test_abc.py

@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: MIT
+
+import abc
+import inspect
+
+import pytest
+
+import attrs
+
+from attr._compat import PY310
+
+
+@pytest.mark.skipif(not PY310, reason="abc.update_abstractmethods is 3.10+")
+class TestUpdateAbstractMethods:
+    def test_abc_implementation(self, slots):
+        """
+        If an attrs class implements an abstract method, it stops being
+        abstract.
+        """
+
+        class Ordered(abc.ABC):
+            @abc.abstractmethod
+            def __lt__(self, other):
+                pass
+
+            @abc.abstractmethod
+            def __le__(self, other):
+                pass
+
+        @attrs.define(order=True, slots=slots)
+        class Concrete(Ordered):
+            x: int
+
+        assert not inspect.isabstract(Concrete)
+        assert Concrete(2) > Concrete(1)
+
+    def test_remain_abstract(self, slots):
+        """
+        If an attrs class inherits from an abstract class but doesn't implement
+        abstract methods, it remains abstract.
+        """
+
+        class A(abc.ABC):
+            @abc.abstractmethod
+            def foo(self):
+                pass
+
+        @attrs.define(slots=slots)
+        class StillAbstract(A):
+            pass
+
+        assert inspect.isabstract(StillAbstract)
+        with pytest.raises(
+            TypeError, match="class StillAbstract with abstract method foo"
+        ):
+            StillAbstract()

tests/test_mypy.yml

@@ -1371,3 +1371,15 @@
       b: str
 
     fields(A)  # E: Argument 1 to "fields" has incompatible type "Type[A]"; expected "Type[AttrsInstance]"
+
+- case: testHasTypeGuard
+  main: |
+    from attrs import define, has
+
+    @define
+    class A:
+        pass
+
+    reveal_type(A)  # N: Revealed type is "def () -> main.A"
+    if has(A):
+        reveal_type(A)  # N: Revealed type is "Type[attr.AttrsInstance]"

tests/typing_example.py

@@ -416,3 +416,8 @@ def accessing_from_attrs() -> None:
     attrs.setters.frozen
     attrs.validators.and_
     attrs.cmp_using
+
+
+foo = object
+if attrs.has(foo) or attr.has(foo):
+    foo.__attrs_attrs__

tox.ini

@@ -61,7 +61,7 @@ commands =
 skip_install = true
 deps = pre-commit
 passenv = HOMEPATH  # needed on Windows
-commands = pre-commit run --all-files
+commands = pre-commit run --all-files --show-diff-on-failure
 
 
 [testenv:manifest]