From b1382ac9f278ded0e4c46fcacd4395782db92e81 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A9gis=20Desgroppes?= <rdesgroppes@gmail.com>
Date: Thu, 16 Apr 2026 14:27:39 +0200
Subject: [PATCH 1/2] gh-148644: propagate PGO job exit code in
 PCbuild/build.bat

Replace the `if "%clean%"=="false" (...)` block with a `goto :RunPgoJob`
so the job runs outside any parenthesized block, where `%ERRORLEVEL%` is
not subject to eager evaluation.

Save the exit code before `call :Kill` resets it, then propagate it if
non-zero.
---
 PCbuild/build.bat | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/PCbuild/build.bat b/PCbuild/build.bat
index 8fb2f096c93c0e..9d2f032f5a9355 100644
--- a/PCbuild/build.bat
+++ b/PCbuild/build.bat
@@ -170,16 +170,20 @@ if "%do_pgo%"=="true" (
     del /s "%dir%\*.pgc"
     del /s "%dir%\..\Lib\*.pyc"
     set conf=PGUpdate
-    if "%clean%"=="false" (
-        echo on
-        call "%dir%\..\python.bat" %pgo_job%
-        @echo off
-        call :Kill
-        set target=Build
-    )
+    if "%clean%"=="false" goto :RunPgoJob
 )
 goto :Build
 
+:RunPgoJob
+echo on
+call "%dir%\..\python.bat" %pgo_job%
+@echo off
+set pgo_errorlevel=%ERRORLEVEL%
+call :Kill
+if %pgo_errorlevel% NEQ 0 exit /B %pgo_errorlevel%
+set target=Build
+goto :Build
+
 :Kill
 echo on
 %MSBUILD% "%dir%\pythoncore.vcxproj" /t:KillPython %verbose%^

From 0ed6ca5ed9edc79a8fd4ad9bef2f60698dc7b0fc Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Fri, 17 Apr 2026 21:45:33 +0000
Subject: [PATCH 2/2] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20blu?=
 =?UTF-8?q?rb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../next/Build/2026-04-17-21-45-32.gh-issue-148644.vwkknh.rst    | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Build/2026-04-17-21-45-32.gh-issue-148644.vwkknh.rst

diff --git a/Misc/NEWS.d/next/Build/2026-04-17-21-45-32.gh-issue-148644.vwkknh.rst b/Misc/NEWS.d/next/Build/2026-04-17-21-45-32.gh-issue-148644.vwkknh.rst
new file mode 100644
index 00000000000000..a0cc9c9358cb26
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2026-04-17-21-45-32.gh-issue-148644.vwkknh.rst
@@ -0,0 +1 @@
+Errors during the PGO training job on Windows are no longer ignored, and a non-zero return code will cause the build to fail.