From: Vineet Kumar <108144301+whyvineet@users.noreply.github.com>
Date: Sun, 5 Jul 2026 19:02:58 +0000 (+0530)
Subject: gh-153141: Fix mutable default argument in _SharedMemoryTracker.__init__ (GH-153142)
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d733b104d53e96584a6881d2772df65ad82573a0;p=thirdparty%2FPython%2Fcpython.git

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.
---

diff --git a/Lib/multiprocessing/managers.py b/Lib/multiprocessing/managers.py
index 91bcf243e78e..11c6e21de90e 100644
--- a/Lib/multiprocessing/managers.py
+++ b/Lib/multiprocessing/managers.py
@@ -1294,9 +1294,9 @@ 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."