Fix Avalonia Designer support

Author: chsbuffer

Directory.Build.props

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <TargetAvaloniaVersion Condition="'$(TargetAvaloniaVersion)' == ''">11.0</TargetAvaloniaVersion>
     <AvaloniaAppHostPackageVersionMajor>0</AvaloniaAppHostPackageVersionMajor>
-    <AvaloniaAppHostPackageVersionPrev>preview.3</AvaloniaAppHostPackageVersionPrev>
+    <AvaloniaAppHostPackageVersionPrev>preview.4</AvaloniaAppHostPackageVersionPrev>
   </PropertyGroup>
 
   <Choose>

src/package-avalonia-apphost/buildTransitive/ChsBuffer.Avalonia.AppHost.targets

@@ -1,6 +1,7 @@
 <Project>
   <PropertyGroup>
     <DisableSkiaHarfBuzzRuntimeCopy Condition="'$(DisableSkiaHarfBuzzRuntimeCopy)' == ''">true</DisableSkiaHarfBuzzRuntimeCopy>
+    <DetectAvaloniaDesigner Condition="'$(DetectAvaloniaDesigner)' == ''">true</DetectAvaloniaDesigner>
   </PropertyGroup>
 
   <PropertyGroup>
@@ -39,6 +40,10 @@
           BeforeTargets="CoreCompile"
           DependsOnTargets="ResolveAvaloniaAppHostActivation"
           Condition="'$(AvaloniaAppHostActive)' == 'true' and Exists('$(_AvaloniaModuleInitializer)')">
+    <PropertyGroup>
+        <DefineConstants Condition="'$(DetectAvaloniaDesigner)' == 'true'">$(DefineConstants);DETECT_AVALONIA_DESIGNER</DefineConstants>
+    </PropertyGroup>
+
     <ItemGroup>
       <Compile Include="$(_AvaloniaModuleInitializer)"
                Link="HostForge\Avalonia\ModuleInitializer.g.cs"
@@ -53,20 +58,6 @@
     <Warning Text="ChsBuffer.Avalonia.AppHost is inactive for TargetFramework='$(TargetFramework)' RuntimeIdentifier='$(RuntimeIdentifier)'. Expected templates under 'template/$(_AvaloniaTemplateTfm)/$(_AvaloniaTemplateRid)' (or default net10.0/win-x64). Host replacement and Skia/HarfBuzz runtime copy suppression are disabled." />
   </Target>
 
-  <Target Name="DisableSkiaHarfBuzzCopyLocalItems"
-          AfterTargets="ResolveReferences"
-          DependsOnTargets="ResolveAvaloniaAppHostActivation"
-          Condition="'$(DisableSkiaHarfBuzzRuntimeCopy)' == 'true' and '$(AvaloniaAppHostActive)' == 'true'">
-    <ItemGroup>
-      <ReferenceCopyLocalPaths Remove="@(ReferenceCopyLocalPaths)"
-                               Condition="$(_AvaloniaSkiaNativeFileNames.Contains(';%(ReferenceCopyLocalPaths.Filename)%(ReferenceCopyLocalPaths.Extension);')) or $(_AvaloniaHarfBuzzNativeFileNames.Contains(';%(ReferenceCopyLocalPaths.Filename)%(ReferenceCopyLocalPaths.Extension);'))" />
-      <NativeCopyLocalItems Remove="@(NativeCopyLocalItems)"
-                            Condition="$(_AvaloniaSkiaNativeFileNames.Contains(';%(NativeCopyLocalItems.Filename)%(NativeCopyLocalItems.Extension);')) or $(_AvaloniaHarfBuzzNativeFileNames.Contains(';%(NativeCopyLocalItems.Filename)%(NativeCopyLocalItems.Extension);'))" />
-      <RuntimeCopyLocalItems Remove="@(RuntimeCopyLocalItems)"
-                             Condition="$(_AvaloniaSkiaNativeFileNames.Contains(';%(RuntimeCopyLocalItems.Filename)%(RuntimeCopyLocalItems.Extension);')) or $(_AvaloniaHarfBuzzNativeFileNames.Contains(';%(RuntimeCopyLocalItems.Filename)%(RuntimeCopyLocalItems.Extension);'))" />
-    </ItemGroup>
-  </Target>
-
   <Target Name="DisableSkiaHarfBuzzPublishItems"
           BeforeTargets="_CopyResolvedFilesToPublishPreserveNewest;_CopyResolvedFilesToPublishAlways"
           DependsOnTargets="ResolveAvaloniaAppHostActivation"

src/package-avalonia-apphost/contentFiles/cs/net10.0/ModuleInitializer.cs

@@ -25,6 +25,9 @@ public static void Init()
 
     private static IntPtr Resolve(string libraryName, Assembly assembly, DllImportSearchPath? searchPath)
     {
+#if DETECT_AVALONIA_DESIGNER
+        if (global::Avalonia.Controls.Design.IsDesignMode) return IntPtr.Zero;
+#endif
         if (NativeDllNames.Contains(libraryName))
         {
             return NativeLibrary.GetMainProgramHandle();

tests/HostForge.AvaloniaAppHost.Tests/AvaloniaAppHostLinuxTests.cs

@@ -44,12 +44,11 @@ public async Task PublishLinuxX64_RunsAndPrintsNativeVersion()
     }
 
     [Test]
-    public async Task DisableSkiaHarfBuzzRuntimeCopy_AffectsBuildAndPublishOutputs_LinuxX64()
+    public async Task DisableSkiaHarfBuzzRuntimeCopy_AffectsPublishOutputs_LinuxX64()
     {
         SwitchRuleCase[] cases =
         [
-            new("net10_build_default_linux", "build", DisableSkiaHarfBuzzRuntimeCopy: null, ExpectNativeRuntimeCopy: false),
-            new("net10_build_copy-switch-false_linux", "build", DisableSkiaHarfBuzzRuntimeCopy: false, ExpectNativeRuntimeCopy: true),
+            new("net10_publish_default_linux", "publish", DisableSkiaHarfBuzzRuntimeCopy: null, ExpectNativeRuntimeCopy: false),
             new("net10_publish_copy-switch-false_linux", "publish", DisableSkiaHarfBuzzRuntimeCopy: false, ExpectNativeRuntimeCopy: true)
         ];
 

tests/HostForge.AvaloniaAppHost.Tests/AvaloniaAppHostTests.cs

@@ -100,12 +100,11 @@ await ExecuteCaseAsync(testCase.Name, async () =>
     }
 
     [Test]
-    public async Task DisableSkiaHarfBuzzRuntimeCopy_AffectsBuildAndPublishOutputs_WinX64()
+    public async Task DisableSkiaHarfBuzzRuntimeCopy_AffectsPublishOutputs_WinX64()
     {
         SwitchRuleCase[] cases =
         [
-            new("net10_build_default", "build", DisableSkiaHarfBuzzRuntimeCopy: null, ExpectNativeRuntimeCopy: false),
-            new("net10_build_copy-switch-false", "build", DisableSkiaHarfBuzzRuntimeCopy: false, ExpectNativeRuntimeCopy: true),
+            new("net10_publish_default", "publish", DisableSkiaHarfBuzzRuntimeCopy: null, ExpectNativeRuntimeCopy: false),
             new("net10_publish_copy-switch-false", "publish", DisableSkiaHarfBuzzRuntimeCopy: false, ExpectNativeRuntimeCopy: true)
         ];
 

tests/HostForge.TestInfra/TestProjectWorkspace.cs

@@ -100,6 +100,8 @@ private static void BuildProjectFile(
             "RestoreAdditionalProjectSources",
             "$(RestoreAdditionalProjectSources);$(AvaloniaAppHostPackageOutputDir)");
 
+        propertyGroup.AddProperty("DetectAvaloniaDesigner", "false");
+
         if (disableSkiaHarfBuzzRuntimeCopy is not null)
         {
             propertyGroup.AddProperty(