Only call super if no existing init subclass (#9)

antonagestam · Mar 20, 2022 · f0ad387 · f0ad387
1 parent 487d347
commit f0ad387
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Showing 2 changed files with 8 additions and 5 deletions.
diff --git a/abcattrs/abcattrs.py b/abcattrs/abcattrs.py
@@ -79,13 +79,15 @@ def check_abstract_class_attributes(cls: type) -> None:
 
 def _init_subclass(
     cls: type,
-    existing_init_subclass: Callable[..., None] = lambda *_, **__: None,
+    existing_init_subclass: Callable[..., None] | None = None,
     *args: Any,
     **kwargs: Any,
 ) -> None:
     """
     __init_subclass__ implementation added to classes decorated with @abstractattrs.
     """
-    super(cls).__init_subclass__()  # type: ignore[misc]
+    if existing_init_subclass is None:
+        super(cls).__init_subclass__()  # type: ignore[misc]
+    else:
+        existing_init_subclass(cls, *args, **kwargs)
     check_abstract_class_attributes(cls)
-    existing_init_subclass(cls, *args, **kwargs)
diff --git a/tests/test_decorator.py b/tests/test_decorator.py
@@ -93,9 +93,10 @@ class A(abc.ABC):
         attr: Abstract[int]
 
     with pytest.raises(UndefinedAbstractAttribute):
-        type("B", (A,), {})
+        type("B", (A,), {}, class_arg="doot")
 
-    init_subclass.assert_not_called()
+    init_subclass.assert_called_once()
+    init_subclass.reset_mock()
 
     class C(A, class_arg="intact"):
         attr = 1