Package ijwhost.dll as native asset for self-contained publish (#11664)

* Package ijwhost.dll as native asset for self-contained publish

After the /clr:pure to /clr:NetCore migration (#11575), DirectWriteForwarder
and System.Printing became mixed-mode C++/CLI assemblies that require
ijwhost.dll at runtime. The DLL was being placed in the managed lib/ folder
where it is not recognized by RuntimeList.xml, causing it to be missing from
self-contained publish output.

Exclude ijwhost.dll from the lib/ packaging and add it as a native asset
under runtimes/win-{arch}/native/ so it is properly included in the runtime
pack manifest.

Fixes #11651

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Move ijwhost.dll packaging logic to Packaging.targets

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: mmanolova-msft

eng/WpfArcadeSdk/tools/Packaging.targets

@@ -89,6 +89,21 @@ $(PreparePackageAssetsDependsOn):
       <DestinationSubFolder Condition="'$(Platform)'=='arm64'">runtimes\win-arm64\native\</DestinationSubFolder>
     </PropertyGroup>
 
+    <!--
+      For managed C++/CLI projects (vcxproj with UseDestinationLibFolder), ijwhost.dll is automatically
+      produced in the output directory but must be packaged as a native assembly under runtimes\<rid>\native\
+      rather than alongside managed assemblies under lib\<tfm>\.
+    -->
+    <PropertyGroup Condition="'$(MSBuildProjectExtension)'=='.vcxproj' and '$(UseDestinationLibFolder)' != ''">
+      <NativeRuntimeSubFolder Condition="'$(Platform)'=='AnyCPU' or '$(Platform)'=='x86' or '$(Platform)'=='Win32'">runtimes\win-x86\native\</NativeRuntimeSubFolder>
+      <NativeRuntimeSubFolder Condition="'$(Platform)'=='x64'">runtimes\win-x64\native\</NativeRuntimeSubFolder>
+      <NativeRuntimeSubFolder Condition="'$(Platform)'=='arm64'">runtimes\win-arm64\native\</NativeRuntimeSubFolder>
+    </PropertyGroup>
+
+    <ItemGroup Condition="'$(MSBuildProjectExtension)'=='.vcxproj' and '$(UseDestinationLibFolder)' != ''">
+      <FileNamesExcludedFromPackaging Include="ijwhost.dll" />
+    </ItemGroup>
+
     <!--
         Instead of showing an error when $(TargetFramework) or $(RuntimeIdentifier) cannot be identified
         we simply do no further work
@@ -118,6 +133,13 @@ $(PreparePackageAssetsDependsOn):
       <Output ItemName="PackageAsset" TaskParameter="Include"/>
     </CreateItem>
 
+    <!-- Route ijwhost.dll to runtimes\<rid>\native\ for managed C++/CLI projects -->
+    <CreateItem Include="$(OutDir)ijwhost.dll"
+                AdditionalMetadata="RelativePath=$(ArtifactsPackagingDir)$(NormalizedPackageName)\$(NativeRuntimeSubFolder)"
+                Condition="'$(NativeRuntimeSubFolder)'!='' and '$(DestinationSubFolder)'!='' and '$(IsPackagingProject)'!='true' and Exists('$(OutDir)ijwhost.dll')">
+      <Output ItemName="PackageAsset" TaskParameter="Include"/>
+    </CreateItem>
+
     <!--
       Normally, .lib files are not included in packaging - projects have to opt in by setting
         <PropertyGroup>

src/Microsoft.DotNet.Wpf/src/DirectWriteForwarder/DirectWriteForwarder.vcxproj

@@ -92,7 +92,7 @@
   <ItemGroup>
     <AdditionalPackageReference Include="$(SystemIOPackagingPackage)" Version="$(SystemIOPackagingVersion)" />
   </ItemGroup>
-  <!-- ijwhost.dll is required for mixed-mode C++/CLI assemblies -->
+  <!-- ijwhost.dll packaging is handled centrally in eng/WpfArcadeSdk/tools/Packaging.targets -->
   <Target Name="AddWindowsBaseDefine" AfterTargets="ResolveProjectReferences">
     <Error Text="Unexpected result from _WindowsBaseReference '@(_WindowsBaseReference->Count())'" Condition="'@(_WindowsBaseReference->Count())' != '1'" />
     <PropertyGroup>

src/Microsoft.DotNet.Wpf/src/System.Printing/System.Printing.vcxproj

@@ -161,7 +161,7 @@
   <ItemGroup>
     <AdditionalPackageReference Include="$(SystemIOPackagingPackage)" Version="$(SystemIOPackagingVersion)" />
   </ItemGroup>
-  <!-- ijwhost.dll is required for mixed-mode C++/CLI assemblies -->
+  <!-- ijwhost.dll packaging is handled centrally in eng/WpfArcadeSdk/tools/Packaging.targets -->
   <Target Name="AddDefineReferences" BeforeTargets="ClCompile" AfterTargets="ResolveReferences" Returns="@(CLCompile)">
     <PropertyGroup>
       <_defineReferences>@(_defineReference->'%(Define)=&lt;%(Identity)&gt;')</_defineReferences>