[Dynamo] Fix NamedTuple hasattr bug (#124531)

Fixes #124402

Pull Request resolved: https://github.com/pytorch/pytorch/pull/124531
Approved by: https://github.com/jansel

test/dynamo/test_functions.py

@@ -1284,6 +1284,22 @@ class FunctionTests(torch._dynamo.test_case.TestCase):
         mytuple = FunctionTests.MyNamedTuple(a, b)
         return mytuple.add(), mytuple.static_method(), mytuple.class_method()
 
+    @make_test
+    def test_namedtuple_hasattr(a, b):
+        mytuple = FunctionTests.MyNamedTuple(a, b)
+
+        def isinstance_namedtuple(obj) -> bool:
+            return (
+                isinstance(obj, tuple)
+                and hasattr(obj, "_asdict")
+                and hasattr(obj, "_fields")
+            )
+
+        if isinstance_namedtuple(mytuple):
+            return a + b
+        else:
+            return a - b
+
     @make_test
     def test_is_quantized(a, b):
         if not a.is_quantized:

torch/_dynamo/variables/lists.py

@@ -586,8 +586,7 @@ class NamedTupleVariable(TupleVariable):
         return self.items[fields.index(name)]
 
     def call_hasattr(self, tx, name: str) -> "VariableTracker":
-        fields = namedtuple_fields(self.tuple_cls)
-        return variables.ConstantVariable.create(name in fields)
+        return variables.ConstantVariable.create(hasattr(self.tuple_cls, name))
 
 
 class SliceVariable(BaseListVariable):