gh-117783: Immortalize objects that use deferred reference counting (#118112)

Deferred reference counting is not fully implemented yet. As a temporary
measure, we immortalize objects that would use deferred reference
counting to avoid multi-threaded scaling bottlenecks.

This is only performed in the free-threaded build once the first
non-main thread is started. Additionally, some tests, including refleak
tests, suppress this behavior.

1 files changed, 4 insertions, 1 deletions

diff --git a/Lib/test/test_weakref.py b/Lib/test/test_weakref.py
index a2f5b9b2902..df90647baee 100644
--- a/Lib/test/test_weakref.py
+++ b/Lib/test/test_weakref.py
@@ -13,7 +13,7 @@ import random
 import textwrap
 
 from test import support
-from test.support import script_helper, ALWAYS_EQ
+from test.support import script_helper, ALWAYS_EQ, suppress_immortalization
 from test.support import gc_collect
 from test.support import import_helper
 from test.support import threading_helper
@@ -651,6 +651,7 @@ class ReferencesTestCase(TestBase):
         # deallocation of c2.
         del c2
 
+    @suppress_immortalization()
     def test_callback_in_cycle(self):
         import gc
 
@@ -743,6 +744,7 @@ class ReferencesTestCase(TestBase):
         del c1, c2, C, D
         gc.collect()
 
+    @suppress_immortalization()
     def test_callback_in_cycle_resurrection(self):
         import gc
 
@@ -878,6 +880,7 @@ class ReferencesTestCase(TestBase):
         # No exception should be raised here
         gc.collect()
 
+    @suppress_immortalization()
     def test_classes(self):
         # Check that classes are weakrefable.
         class A(object):