add news entry.

LindaSummer · LindaSummer · commit 002b3a639e0d · 2025-12-14T10:34:17.000+08:00
diff --git a/Misc/NEWS.d/next/Library/2025-12-13-23-26-42.gh-issue-142495.I88Uv_.rst b/Misc/NEWS.d/next/Library/2025-12-13-23-26-42.gh-issue-142495.I88Uv_.rst
@@ -0,0 +1,3 @@
+:class:`collections.defaultdict` now prioritizes :meth:`~object.__setitem__`
+when inserting default values from ``default_factory``. This prevents race
+conditions where a default value would overwrite a value set by another thread.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	+:class:`collections.defaultdict` now prioritizes :meth:`~object.__setitem__`
	`2`	+when inserting default values from ``default_factory``. This prevents race
	`3`	`+conditions where a default value would overwrite a value set by another thread.`