Preserve qualifier on optional factory compat alias

test/unit/test_inject_from_container_optional_types.py

@@ -71,6 +71,30 @@ def make_foo() -> Foo | None:
     assert inst is container.get(Foo | None)
 
 
+def test_optional_factory_with_qualifier() -> None:
+    # https://github.com/maldoinc/wireup/issues/138
+    # A factory returning Optional[T] with a qualifier must preserve the qualifier
+    # on the backwards-compatibility alias factory created for the raw type T.
+    @wireup.injectable
+    class AuthContext:
+        pass
+
+    @wireup.injectable
+    def require_authentication() -> AuthContext:
+        return AuthContext()
+
+    @wireup.injectable(qualifier="optional")
+    def maybe_get_authentication() -> AuthContext | None:
+        return None
+
+    container = wireup.create_sync_container(
+        injectables=[require_authentication, maybe_get_authentication],
+    )
+
+    assert isinstance(container.get(AuthContext), AuthContext)
+    assert container.get(AuthContext | None, qualifier="optional") is None
+
+
 def test_registering_optional_and_plain_type_raises_duplicate() -> None:
     @wireup.injectable
     class Foo:

wireup/ioc/registry.py

@@ -393,12 +393,17 @@ def compat_fn(raw_type_instance: Any) -> Any:
 
                 return raw_type_instance
 
+            # The alias factory depends on the normalized Optional[T] instance. When the
+            # original factory was registered with a qualifier, carry it over so the
+            # dependency resolves to the qualified factory instead of an unqualified one.
+            raw_type_annotation = klass if qualifier is None else Annotated[klass, InjectableQualifier(qualifier)]
+
             compat_fn.__signature__ = inspect.Signature(  # type: ignore[attr-defined]
                 parameters=[
                     inspect.Parameter(
                         "raw_type_instance",
                         kind=inspect.Parameter.POSITIONAL_OR_KEYWORD,
-                        annotation=klass,
+                        annotation=raw_type_annotation,
                     )
                 ],
             )