[Python-checkins] bpo-43298: Improved error message when building without the Windows SDK installed (GH-26800) (#26803)

[ambv]

https://github.com/python/cpython/commit/e7009f4f9a6a55036ef628a07bedc8dab1aa851e
commit: e7009f4f9a6a55036ef628a07bedc8dab1aa851e
branch: 3.9
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: ambv <lukasz at langa.pl>
date: 2021-07-12T17:11:33+02:00
summary:

bpo-43298: Improved error message when building without the Windows SDK installed (GH-26800) (#26803)

(cherry picked from commit 80190b3e533097b55077becddc75423318ab2371)

Co-authored-by: Steve Dower <steve.dower at python.org>

files:
A Misc/NEWS.d/next/Build/2021-06-19-11-50-03.bpo-43298.9ircMb.rst
M PCbuild/python.props

diff --git a/Misc/NEWS.d/next/Build/2021-06-19-11-50-03.bpo-43298.9ircMb.rst b/Misc/NEWS.d/next/Build/2021-06-19-11-50-03.bpo-43298.9ircMb.rst
new file mode 100644
index 00000000000000..3bdc24b147a3ef
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2021-06-19-11-50-03.bpo-43298.9ircMb.rst
@@ -0,0 +1 @@
+Improved error message when building without a Windows SDK installed.
diff --git a/PCbuild/python.props b/PCbuild/python.props
index acbf4e005ec5ba..60625101b47287 100644
--- a/PCbuild/python.props
+++ b/PCbuild/python.props
@@ -109,9 +109,18 @@
 
     <!-- The minimum allowed SDK version to use for building -->
     <DefaultWindowsSDKVersion>10.0.10586.0</DefaultWindowsSDKVersion>
-    <DefaultWindowsSDKVersion Condition="$([System.Version]::Parse($(_RegistryVersion))) > $([System.Version]::Parse($(DefaultWindowsSDKVersion)))">$(_RegistryVersion)</DefaultWindowsSDKVersion>
+    <DefaultWindowsSDKVersion Condition="$(_RegistryVersion) != '' and $([System.Version]::Parse($(_RegistryVersion))) > $([System.Version]::Parse($(DefaultWindowsSDKVersion)))">$(_RegistryVersion)</DefaultWindowsSDKVersion>
   </PropertyGroup>
-  
+
+  <Target Name="_CheckWindowsSDKFound" BeforeTargets="_CheckWindowsSDKInstalled" Condition="$(_RegistryVersion) == ''">
+    <PropertyGroup>
+      <_Message>Failed to locate a Windows SDK installation.</_Message>
+      <_Message>$(_Message) If the build fails, please use the Visual Studio Installer to install the Windows SDK.</_Message>
+      <_Message>$(_Message) (Ignore the version number specified in the error message and select the latest.)</_Message>
+    </PropertyGroup>
+    <Warning Text="$(_Message)" />
+  </Target>
+
   <PropertyGroup Condition="$(WindowsTargetPlatformVersion) == ''">
     <WindowsTargetPlatformVersion>$(DefaultWindowsSDKVersion)</WindowsTargetPlatformVersion>
   </PropertyGroup>
@@ -176,7 +185,7 @@
     <ReleaseLevelNumber Condition="$(_ReleaseLevel) == 'b'">11</ReleaseLevelNumber>
     <ReleaseLevelNumber Condition="$(_ReleaseLevel) == 'rc'">12</ReleaseLevelNumber>
   </PropertyGroup>
-  
+
   <PropertyGroup>
     <PythonVersionNumber>$(MajorVersionNumber).$(MinorVersionNumber).$(MicroVersionNumber)</PythonVersionNumber>
     <PythonVersion>$(MajorVersionNumber).$(MinorVersionNumber).$(MicroVersionNumber)$(ReleaseLevelName)</PythonVersion>