GH-144679: When building with VS 2026 on Windows, use PlatformToolset v145 by default (GH-144680)

Author: chris-eibl

Misc/NEWS.d/next/Build/2026-02-10-18-26-04.gh-issue-144679.FIH73W.rst

@@ -0,0 +1,2 @@
+When building with Visual Studio 2026 (Version 18), use PlatformToolSet v145
+by default. Patch by Chris Eibl.

PCbuild/python.props

@@ -11,7 +11,7 @@
 
     We set BasePlatformToolset for ICC's benefit, it's otherwise ignored.
     -->
-    <BasePlatformToolset Condition="'$(BasePlatformToolset)' == '' and '$(VisualStudioVersion)' == '18.0'">v143</BasePlatformToolset>
+    <BasePlatformToolset Condition="'$(BasePlatformToolset)' == '' and '$(VisualStudioVersion)' == '18.0'">v145</BasePlatformToolset>
     <BasePlatformToolset Condition="'$(BasePlatformToolset)' == '' and '$(VisualStudioVersion)' == '17.0'">v143</BasePlatformToolset>
     <BasePlatformToolset Condition="'$(BasePlatformToolset)' == '' and '$(VisualStudioVersion)' == '16.0'">v142</BasePlatformToolset>
     <BasePlatformToolset Condition="'$(BasePlatformToolset)' == '' and ('$(MSBuildToolsVersion)' == '15.0' or '$(VisualStudioVersion)' == '15.0')">v141</BasePlatformToolset>

PCbuild/pythoncore.vcxproj

@@ -730,7 +730,7 @@
       </ClCompile>
     </ItemGroup>
   </Target>
-  <Target Name="_WarnAboutToolset" BeforeTargets="PrepareForBuild" Condition="$(PlatformToolset) != 'v141' and $(PlatformToolset) != 'v142' and $(PlatformToolset) != 'v143'">
+  <Target Name="_WarnAboutToolset" BeforeTargets="PrepareForBuild" Condition="$(PlatformToolset) != 'v143' and $(PlatformToolset) != 'v145'">
     <Warning Text="Toolset $(PlatformToolset) is not used for official builds. Your build may have errors or incompatibilities." />
   </Target>
   <Target Name="_WarnAboutZlib" BeforeTargets="PrepareForBuild" Condition="!$(IncludeExternals)">

Tools/msi/bundle/bootstrap/pythonba.vcxproj

@@ -21,6 +21,7 @@
   <PropertyGroup Label="Globals">
     <Configuration Condition="'$(Configuration)' == ''">Release</Configuration>
     <Platform Condition="'$(Platform)' == ''">Win32</Platform>
+    <PlatformToolset Condition="'$(PlatformToolset)' == '' and '$(VisualStudioVersion)' == '18.0'">v145</PlatformToolset>
     <PlatformToolset Condition="'$(PlatformToolset)' == '' and '$(VisualStudioVersion)' == '17.0'">v143</PlatformToolset>
     <PlatformToolset Condition="'$(PlatformToolset)' == '' and '$(VisualStudioVersion)' == '16.0'">v142</PlatformToolset>
     <PlatformToolset Condition="'$(PlatformToolset)' == '' and ('$(MSBuildToolsVersion)' == '15.0' or '$(VisualStudioVersion)' == '15.0')">v141</PlatformToolset>