[dynamo][user-defined] Improve getattr_static for user_defined objects (#133742)

Fixes https://github.com/pytorch/pytorch/issues/133607

Pull Request resolved: https://github.com/pytorch/pytorch/pull/133742
Approved by: https://github.com/Skylion007, https://github.com/jansel

test/dynamo/test_repros.py

@@ -5018,6 +5018,28 @@ def forward(self, s0 : torch.SymInt, s1 : torch.SymInt, L_x_ : torch.Tensor):
         self.assertEqual(v.data.shape, (10, 20))
         self.assertEqual(type(v), Matrix)
 
+    def test_classmethod_with_slots(self):
+        class Mock:
+            __slots__ = ("_a",)
+
+            def __init__(self):
+                self._a = 2
+
+            @classmethod
+            def _m(cls):
+                return 3
+
+            def run(self, x):
+                return torch.sin(x) * self._a * self._m()
+
+        def fn(x):
+            mock = Mock()
+            return mock.run(x)
+
+        opt_fn = torch.compile(fn, backend="eager", fullgraph=True)
+        x = torch.randn(4)
+        self.assertEqual(fn(x), opt_fn(x))
+
     def test_nn_parametrize(self):
         class Module(nn.Module):
             def __init__(self) -> None:

torch/_dynamo/variables/user_defined.py

@@ -8,7 +8,6 @@ import inspect
 import itertools
 import random
 import sys
-import threading
 import types
 import warnings
 from typing import Dict, Generic, List, TYPE_CHECKING
@@ -890,23 +889,30 @@ class UserDefinedObjectVariable(UserDefinedVariable):
         return get_custom_getattr(self.value)
 
     def _getattr_static(self, name):
+        subobj = inspect.getattr_static(self.value, name, NO_SUCH_SUBOBJ)
+        import _collections
+
+        # In some cases, we have to do dynamic lookup because getattr_static is not enough. For example, threading.local
+        # has side-effect free __getattribute__ and the attribute is not visible without a dynamic lookup.
         if (
-            isinstance(self.value, PyTreeSpec)
-            or "__slots__" in self.value.__class__.__dict__
-            or type(self.value) == threading.local
+            subobj is NO_SUCH_SUBOBJ  # e.g., threading.local
+            or isinstance(
+                subobj, _collections._tuplegetter
+            )  # namedtuple fields are represented by _tuplegetter
+            or (
+                inspect.ismemberdescriptor(subobj) and name in self.value.__slots__
+            )  # handle memberdecriptor and slots
+            or (
+                isinstance(subobj, property)
+                and isinstance(
+                    subobj.fget, types.BuiltinFunctionType
+                )  # property with C-defined fget
+            )
         ):
-            try:
-                cls_var = inspect.getattr_static(
-                    self.value.__class__, name, NO_SUCH_SUBOBJ
-                )
-                if cls_var is not NO_SUCH_SUBOBJ and name not in self.value.__dict__:
-                    # maybe user-defined @property that we need to inline
-                    return cls_var
-            except AttributeError:
-                pass  # __slots__
-            subobj = getattr(self.value, name)
-        else:
-            subobj = inspect.getattr_static(self.value, name)
+            # Call __getattribute__, we have already checked that this is not overridden and side-effect free. We don't
+            # want to call getattr because it can be user-overridden.
+            subobj = self.value.__getattribute__(name)
+
         return subobj
 
     def has_key_in_generic_dict(self, tx: "InstructionTranslator", key):