fix @db.declared_attr(with_table=True) override

* so that overwritten methods are not called
* refs #659

Author: fantix

src/gino/declarative.py

@@ -116,8 +116,12 @@ def __new__(mcs, name, bases, namespace, **kwargs):
         if rv.__table__ is None:
             rv.__table__ = getattr(rv, "_init_table")(rv)
 
-        for each_cls in rv.__mro__[::-1]:
+        visited = set()
+        for each_cls in rv.__mro__:
             for k, v in getattr(each_cls, "__namespace__", each_cls.__dict__).items():
+                if k in visited:
+                    continue
+                visited.add(k)
                 if callable(v) and getattr(v, "__declared_attr_with_table__", False):
                     setattr(rv, k, v(rv))
         return rv

tests/test_declarative.py

@@ -373,3 +373,28 @@ def field(self):
 
     assert len(Model.__table__.columns) == 1
     assert Model().field == "field is a const value"
+
+
+async def test_declared_attr_with_table_override():
+    mixin_called = False
+    override_called = False
+
+    class ModelMixin:
+        @db.declared_attr(with_table=True)
+        def some(self):
+            nonlocal mixin_called
+            mixin_called = True
+            return "mixin"
+
+    class Model(db.Model, ModelMixin):
+        __tablename__ = "model8"
+
+        @db.declared_attr(with_table=True)
+        def some(self):
+            nonlocal override_called
+            override_called = True
+            return "override"
+
+    assert Model.some == "override"
+    assert not mixin_called
+    assert override_called