From: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Date: Sun, 5 Jul 2026 19:36:15 +0000 (+0200)
Subject: [3.13] gh-153141: Fix mutable default argument in _SharedMemoryTracker.__init__ ... 
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e9f8969cf2fba0eb208bde49990d07b91bacc0f6;p=thirdparty%2FPython%2Fcpython.git

[3.13] gh-153141: Fix mutable default argument in _SharedMemoryTracker.__init__ (GH-153142) (#153147)

gh-153141: Fix mutable default argument in _SharedMemoryTracker.__init__ (GH-153142)

Fix default argument for segment_names in _SharedMemoryTracker constructor to not use a mutable list.
(cherry picked from commit d733b104d53e96584a6881d2772df65ad82573a0)

Co-authored-by: Vineet Kumar <108144301+whyvineet@users.noreply.github.com>
---

diff --git a/Lib/multiprocessing/managers.py b/Lib/multiprocessing/managers.py
index ef791c275168..d14530430035 100644
--- a/Lib/multiprocessing/managers.py
+++ b/Lib/multiprocessing/managers.py
@@ -1253,9 +1253,9 @@ if HAS_SHMEM:
     class _SharedMemoryTracker:
         "Manages one or more shared memory segments."
 
-        def __init__(self, name, segment_names=[]):
+        def __init__(self, name, segment_names=None):
             self.shared_memory_context_name = name
-            self.segment_names = segment_names
+            self.segment_names = [] if segment_names is None else segment_names
 
         def register_segment(self, segment_name):
             "Adds the supplied shared memory block name to tracker."