[dynamo] Support delattr on result of torch.compile(module) (pytorch#152741)

This is essentially a follow-up on pytorch#122098, where we added support of
`getattr` and `setattr` on result of `torch.compile(module)`, but didn't
add support for `delattr`.

Fixes pytorch#150711.

Pull Request resolved: pytorch#152741
Approved by: https://github.com/anijain2305
ghstack dependencies: pytorch#152740

Author: StrongerXi

test/dynamo/test_modules.py

@@ -3047,6 +3047,19 @@ def forward(self, inp):
 
         self.assertEqual(model.x, compiled_model.x)
 
+    def test_delattr_on_compiled_module(self):
+        class Mod(torch.nn.Module):
+            def forward(self, x):
+                return x + 1
+
+        model = Mod()
+        compiled_model = torch.compile(model)
+        compiled_model.foo = 42
+        del compiled_model.foo
+
+        self.assertFalse(hasattr(model, "foo"))
+        self.assertFalse(hasattr(compiled_model, "foo"))
+
     def test_globals_change_in_other_file(self):
         @torch.compile(backend="eager", fullgraph=True)
         def fn(x):

torch/_dynamo/eval_frame.py

@@ -389,6 +389,15 @@ def __setattr__(self, name, val) -> None:
             return super().__setattr__(name, val)
         return setattr(self._orig_mod, name, val)
 
+    def __delattr__(self, name):
+        # This mirrors `__setattr__`
+        if hasattr(type(self), name):
+            return super().__delattr__(name)
+
+        if name in OptimizedModule._opt_mod_attributes:
+            return super().__delattr__(name)
+        return delattr(self._orig_mod, name)
+
     def _call_lazy_check(self, *args, **kwargs):
         if (
             hasattr(self._orig_mod, "_initialize_hook")