From 38f8e7326279d9187736065852cb7651c774d582 Mon Sep 17 00:00:00 2001
From: Austin Lamb <austin.lamb@microsoft.com>
Date: Fri, 19 Feb 2021 15:27:01 -0800
Subject: [PATCH 1/2] [3.9] bpo-42825: Enable /OPT:REF (GH-24098)

We explicitly disable /OPT:ICF as some manual optimisations depend on some functions still having distinct pointers (such as wrap_binary_func and wrap_binary_func_l).

(cherry picked from commit b4af629f4d4868ef74ee298d66259fae78c7fd89)
---
 PCbuild/pyproject.props | 1 +
 1 file changed, 1 insertion(+)

diff --git a/PCbuild/pyproject.props b/PCbuild/pyproject.props
index 2b4be392da47ae6..d492b71dfbaa3d2 100644
--- a/PCbuild/pyproject.props
+++ b/PCbuild/pyproject.props
@@ -74,6 +74,7 @@
       <LinkTimeCodeGeneration Condition="$(SupportPGO) and $(Configuration) == 'PGInstrument'">PGInstrument</LinkTimeCodeGeneration>
       <LinkTimeCodeGeneration Condition="$(SupportPGO) and $(Configuration) == 'PGUpdate'">PGUpdate</LinkTimeCodeGeneration>
       <AdditionalDependencies>advapi32.lib;shell32.lib;ole32.lib;oleaut32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <AdditionalOptions Condition="$(Configuration) != 'Debug'">/OPT:REF,NOICF %(AdditionalOptions)</AdditionalOptions>
     </Link>
     <Lib>
       <LinkTimeCodeGeneration Condition="$(Configuration) == 'Release'">true</LinkTimeCodeGeneration>

From d04e6658e19aceab307637944b57d0507bae973c Mon Sep 17 00:00:00 2001
From: icanhasmath <marcg@activestate.com>
Date: Thu, 29 Oct 2026 08:12:02 -0500
Subject: [PATCH 2/2] Update version to 3.9.25.3 and add release notes

ActiveState release of the end-of-life 3.9 line: the bpo-42825
/OPT:REF,NOICF linker setting, so Windows builds made with Visual
Studio 2022 keep wrap_binaryfunc and wrap_binaryfunc_l distinct.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 Doc/whatsnew/3.9.rst | 17 +++++++++++++++++
 Include/patchlevel.h |  2 +-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/Doc/whatsnew/3.9.rst b/Doc/whatsnew/3.9.rst
index a9e747a8c37e946..359e88d0b8bff76 100644
--- a/Doc/whatsnew/3.9.rst
+++ b/Doc/whatsnew/3.9.rst
@@ -1847,3 +1847,20 @@ tempfile
   a :exc:`PermissionError` is no longer masked by :exc:`NotADirectoryError`
   (:issue:`43153`), and cleanup no longer recurses endlessly when the
   temporary directory itself cannot be removed (:gh:`79325`).
+
+
+Notable changes in 3.9.25.3
+===========================
+
+This is an ActiveState release of the 3.9 line, on top of 3.9.25.2.
+
+Build Changes
+-------------
+
+* Windows release builds now link with ``/OPT:REF,NOICF``.  With identical
+  COMDAT folding enabled, newer Visual Studio linkers merge two internal slot
+  wrappers whose code is identical, and the type machinery relies on their
+  addresses being different.  On such builds, ``+`` with an instance of a
+  subclass of a built-in type (for example an :class:`int` or
+  :class:`datetime.datetime` subclass) returned :data:`NotImplemented`
+  instead of raising :exc:`TypeError`.  (Backport of :issue:`42825`.)
diff --git a/Include/patchlevel.h b/Include/patchlevel.h
index 988aba035a6fa8b..9db78558a0ceac4 100644
--- a/Include/patchlevel.h
+++ b/Include/patchlevel.h
@@ -23,7 +23,7 @@
 #define PY_RELEASE_SERIAL       0
 
 /* Version as a string */
-#define PY_VERSION              "3.9.25.2"
+#define PY_VERSION              "3.9.25.3"
 /*--end constants--*/
 
 /* Version as a single 4-byte hex number, e.g. 0x010502B2 == 1.5.2b2.