[dynamo] Add test to ensure we don't print fx graph upon data dependent graph break (#153416)

StrongerXi · pytorchmergebot · commit 8ac82a1d209d · 2025-05-13T18:28:02.000Z
This adds a regression test for #149831, also as part of getting it cherry-picked into 2.7.1. Pull Request resolved: #153416 Approved by: https://github.com/atalman
diff --git a/test/dynamo/test_repros.py b/test/dynamo/test_repros.py
@@ -15,6 +15,7 @@
 import itertools
 import os
 import random
+import sys
 import types
 import typing
 import unittest
@@ -7153,6 +7154,31 @@ def fn(x):
         x = torch.randn(4)
         self.assertEqual(fn(x), opt_fn(x))
 
+    def test_data_dependent_error_log_no_print(self):
+        # This is a regression test case for
+        # https://github.com/pytorch/pytorch/pull/149831
+        from io import StringIO
+
+        capturedOutput = StringIO()
+        sys.stderr = capturedOutput
+
+        @torch.compile(fullgraph=True)
+        def func(a):
+            if a.sum() > 0:
+                return a + 1
+            return a + 2
+
+        a = torch.rand(10, 10)
+        try:
+            func(a)
+        except Exception:
+            pass
+        sys.stderr = sys.__stderr__
+
+        # Make sure we don't _print_ out the graph module.
+        output = capturedOutput.getvalue()
+        self.assertNotIn("class GraphModule", output)
+
 
 instantiate_parametrized_tests(ReproTests)
 
