Added test and explanation for assigning __init__.__doc__

equinox/_module.py

@@ -212,7 +212,19 @@ def __new__(mcs, name, bases, dict_, /, strict: bool = False, **kwargs):
         # (This part has to happen after dataclass registration.)
         _has_dataclass_init[cls] = _init
         if _init:
+            # Assign `__doc__` in case its been manually overriden:
+            # ```
+            # class Foo(eqx.Module):
+            #     x: int
+            #
+            # Foo.__init__.__doc__ = "Foo should be called with with an integer `x`."
+            #
+            # class Bar(Foo):
+            #     pass
+            # ```
+            # With `Bar.__init__.__doc__` used during documentation generation.
             cls.__init__.__doc__ = init_doc  # pyright: ignore
+            # TODO: is this next line still necessary?
             cls.__init__.__module__ = cls.__module__
         # [Step 6] Check strict abstract modules.
         if strict:

tests/test_module.py

@@ -579,3 +579,18 @@ class C(B):
     B()
     C()
     assert not A.called
+
+
+def test_inherit_doc():
+    # This is not what dataclasses do by default -- they would set `B.__init__.__doc__`
+    # to `None`
+
+    class A(eqx.Module):
+        pass
+
+    A.__init__.__doc__ = "Hey there!"
+
+    class B(A):
+        pass
+
+    assert B.__init__.__doc__ == "Hey there!"