Fix __init__ + __init_subclass__ + AbstractClassVar

equinox/_module.py

@@ -698,7 +698,10 @@ def _is_abstract(cls):
 
 
 class _Initable:
-    pass
+    # Prevent `__init_subclass__` from triggering when creating initable versions of
+    # classes.
+    def __init_subclass__(cls, **kwargs):
+        del kwargs
 
 
 _transform_types = {
@@ -805,7 +808,7 @@ def _make_initable(
     else:
         field_names = {field.name for field in dataclasses.fields(cls)}
 
-    class _InitableModule(cls, _Initable):
+    class _InitableModule(_Initable, cls):
         pass
 
     def __setattr__(self, name, value):

tests/test_module.py

@@ -1204,3 +1204,20 @@ class E(D, B):
     assert called_a
     assert called_b
     assert called_d
+
+
+# https://github.com/patrick-kidger/equinox/issues/858
+def test_init_subclass_and_abstract_class_var():
+    class Parent(eqx.Module):
+        abs_cls_var: eqx.AbstractClassVar[str]
+
+        def __init__(self):
+            pass
+
+        def __init_subclass__(cls):
+            cls.abs_cls_var
+
+    class Child(Parent):
+        abs_cls_var = "foo"
+
+    Child()  # pyright: ignore[reportCallIssue]