[dynamo] raise observed exception for module attribute errors

williamwen42 · williamwen42 · commit 660888ac2872 · 2025-05-17T00:28:09.000Z
ghstack-source-id: 42de38f Pull Request resolved: #153659
diff --git a/test/dynamo/test_repros.py b/test/dynamo/test_repros.py
@@ -7176,6 +7176,23 @@ def func(a):
         output = capturedOutput.getvalue()
         self.assertNotIn("class GraphModule", output)
 
+    def test_module_attribute_error(self):
+        @torch.compile(backend="eager")
+        def f1(x):
+            return torch._bar(x)
+
+        @torch.compile(backend="eager")
+        def f2(x):
+            try:
+                return torch._bar(x)
+            except AttributeError:
+                return x + 1
+
+        with self.assertRaises(AttributeError):
+            f1(torch.ones(3))
+
+        self.assertEqual(f2(torch.ones(3)), torch.ones(3) + 1)
+
 
 instantiate_parametrized_tests(ReproTests)
 
diff --git a/torch/_dynamo/variables/misc.py b/torch/_dynamo/variables/misc.py
@@ -1270,7 +1270,10 @@ def var_getattr(self, tx: "InstructionTranslator", name):
             return tx.output.side_effects.load_attr(self, name)
 
         if self.is_torch or name not in self.value.__dict__:
-            attr_value = getattr(self.value, name)
+            try:
+                attr_value = getattr(self.value, name)
+            except AttributeError:
+                raise_observed_exception(AttributeError, tx)
         else:
             attr_value = self.value.__dict__[name]
 
