gh-142631: enable deferred reference counting on functools.lru_cache objects

Lib/test/test_dbm.py

@@ -4,7 +4,7 @@
 import dbm
 import os
 from test.support import import_helper
-from test.support import os_helper
+from test.support import os_helper, gc_collect
 
 
 try:
@@ -58,6 +58,7 @@ def init_db(self):
         for k in self._dict:
             f[k.encode("ascii")] = self._dict[k]
         f.close()
+        gc_collect()
 
     def keys_helper(self, f):
         keys = sorted(k.decode("ascii") for k in f.keys())
@@ -181,6 +182,7 @@ def _calculate_db_size(db_path):
                 f[k.encode('ascii')] = self._dict[k] * 100000
             db_keys = list(f.keys())
 
+        gc_collect()
         # Make sure to calculate size of database only after file is closed to ensure file content are flushed to disk.
         size_before = _calculate_db_size(os.path.dirname(_fname))
 
@@ -191,6 +193,7 @@ def _calculate_db_size(db_path):
                 del f[k]
             f.reorganize()
 
+        gc_collect()
         # Make sure to calculate size of database only after file is closed to ensure file content are flushed to disk.
         size_after = _calculate_db_size(os.path.dirname(_fname))
 

Lib/test/test_dbm_sqlite3.py

@@ -5,7 +5,7 @@
 from contextlib import closing
 from functools import partial
 from pathlib import Path
-from test.support import import_helper, os_helper
+from test.support import import_helper, os_helper, gc_collect
 
 dbm_sqlite3 = import_helper.import_module("dbm.sqlite3")
 # N.B. The test will fail on some platforms without sqlite3
@@ -32,7 +32,6 @@ def tearDown(self):
         for suffix in "", "-wal", "-shm":
             os_helper.unlink(self.filename + suffix)
 
-
 class URI(unittest.TestCase):
 
     def test_uri_substitutions(self):
@@ -72,6 +71,7 @@ def setUp(self):
         with dbm_sqlite3.open(self.filename, "w") as db:
             db[b"key1"] = "value1"
             db[b"key2"] = "value2"
+        gc_collect()
         self.db = dbm_sqlite3.open(self.filename, "r")
 
     def tearDown(self):
@@ -112,6 +112,7 @@ def setUp(self):
 
     def test_readonly_file_read(self):
         os.chmod(self.db_path, stat.S_IREAD)
+        gc_collect()
         with dbm_sqlite3.open(self.db_path, "r") as db:
             self.assertEqual(db[b"key"], b"value")
 
@@ -123,6 +124,7 @@ def test_readonly_file_write(self):
 
     def test_readonly_dir_read(self):
         os.chmod(self.test_dir, stat.S_IREAD | stat.S_IEXEC)
+        gc_collect()
         with dbm_sqlite3.open(self.db_path, "r") as db:
             self.assertEqual(db[b"key"], b"value")
 
@@ -134,6 +136,7 @@ def test_readonly_dir_write(self):
                 modified = True  # on Windows and macOS
             except dbm_sqlite3.error:
                 modified = False
+        gc_collect()
         with dbm_sqlite3.open(self.db_path, "r") as db:
             if modified:
                 self.assertEqual(db[b"newkey"], b"newvalue")
@@ -350,6 +353,7 @@ def test_corrupt_readwrite(self):
                 check(fn=self.len_)
 
     def test_corrupt_force_new(self):
+        gc_collect()
         with closing(dbm_sqlite3.open(self.filename, "n")) as db:
             db["foo"] = "write"
             _ = db[b"foo"]

Misc/NEWS.d/next/Library/2025-12-12-14-19-19.gh-issue-142631.SQ88Sh.rst

@@ -0,0 +1 @@
+Enable deferred reference counting on :class:`functools.lru_cache` objects for better scaling in free-threaded builds. Patch by Kumar Aditya.

Modules/_functoolsmodule.c

@@ -1656,6 +1656,7 @@ lru_cache_new(PyTypeObject *type, PyObject *args, PyObject *kw)
     obj->cache_info_type = Py_NewRef(cache_info_type);
     obj->dict = NULL;
     obj->weakreflist = NULL;
+    _PyObject_SetDeferredRefcount((PyObject *)obj);
     return (PyObject *)obj;
 }