[3.13] deal with exec() semantic change in test_cond_no_dynamo_cache_limit (#140401)

williamwen42 · pytorchmergebot · commit 72943ba82376 · 2024-11-18T22:06:47.000Z
https://peps.python.org/pep-0667/ changed the semantics of `eval/exec` in 3.13 so that changes to locals no longer propagate (but globals do). This is to make the behavior predictable since in the past, the locals may or may not update based on various mysterious conditions. Other test sites may need updating too. Pull Request resolved: #140401 Approved by: https://github.com/ydwu4, https://github.com/zou3519
diff --git a/test/functorch/test_control_flow.py b/test/functorch/test_control_flow.py
@@ -5334,16 +5334,19 @@ def foo(x, true_fn, false_fn):
         exp_out = inp.sin()
         iter_n = torch._dynamo.config.cache_size_limit + 1
 
-        # Need this because Dynamo checks lambda code ID not object itself.
-        def make_dummy_fn(op):
-            exec(f"temp = lambda x: x.{op}()")
-            return locals()["temp"]
+        # Need functions that cause recompilations
+        def get_dummy_fns(str):
+            def dummy_cos(x):
+                return x.cos() + len(str) - len(str)
 
-        for _ in range(iter_n):
-            # each lambda has a different object id thus fails the guard
-            self.assertEqual(
-                foo(inp, make_dummy_fn("cos"), make_dummy_fn("sin")), exp_out
-            )
+            def dummy_sin(x):
+                return x.sin() + len(str) - len(str)
+
+            return dummy_cos, dummy_sin
+
+        for i in range(iter_n):
+            # we fail guards each iter because `str(i)` is different
+            self.assertEqual(foo(inp, *get_dummy_fns(str(i))), exp_out)
 
         # each iteration captures a cond and a getitem from the tuple output
         self.assertEqual(counters["stats"]["calls_captured"], iter_n * 2)
