Fix intermediate path for service worker assets (#21128)

src/Components/WebAssembly/Build/src/targets/ServiceWorkerAssetsManifest.targets

@@ -5,7 +5,7 @@
     BeforeTargets="_ResolveBlazorOutputs;_ResolveBlazorFilesToCompress">
 
     <PropertyGroup>
-      <_ServiceWorkerAssetsManifestIntermediateOutputPath>$(_BlazorIntermediateOutputPath)$(ServiceWorkerAssetsManifest)</_ServiceWorkerAssetsManifestIntermediateOutputPath>
+      <_ServiceWorkerAssetsManifestIntermediateOutputPath>$([MSBuild]::MakeRelative($(MSBuildProjectDirectory), $(_BlazorIntermediateOutputPath)))$(ServiceWorkerAssetsManifest)</_ServiceWorkerAssetsManifestIntermediateOutputPath>
       <_ServiceWorkerAssetsManifestFullPath>$([System.IO.Path]::GetFullPath('$(MSBuildProjectDirectory)/$(_ServiceWorkerAssetsManifestIntermediateOutputPath)'))</_ServiceWorkerAssetsManifestFullPath>
     </PropertyGroup>
 
@@ -19,7 +19,7 @@
         <SourceId>$(PackageId)</SourceId>
         <ContentRoot>$([MSBuild]::NormalizeDirectory('$(TargetDir)wwwroot\'))</ContentRoot>
         <BasePath>$(StaticWebAssetBasePath)</BasePath>
-        <RelativePath>$([MSBuild]::MakeRelative($([System.IO.Path]::GetFullPath('$(MSBuildProjectDirectory)/$(_BlazorIntermediateOutputPath)')), $(_ServiceWorkerAssetsManifestFullPath)))</RelativePath>
+        <RelativePath>$(ServiceWorkerAssetsManifest)</RelativePath>
       </_ManifestStaticWebAsset>
 
       <StaticWebAsset Include="@(_ManifestStaticWebAsset)" />

src/Components/WebAssembly/Build/test/BuildIntegrationTests/BuildIntegrationTest.cs

@@ -325,6 +325,30 @@ namespace Microsoft.AspNetCore.Components.WebAssembly.Build
             Assert.FileDoesNotExist(result, buildOutputDirectory, "wwwroot", "_framework", "_bin", "I18N.West.dll");
         }
 
+        [Fact]
+        public async Task Build_WithCustomOutputPath_Works()
+        {
+            // Arrange
+            using var project = ProjectDirectory.Create("standalone", additionalProjects: new[] { "razorclasslibrary" });
+
+            project.AddDirectoryBuildContent(
+@"<PropertyGroup>
+    <BaseOutputPath>$(MSBuildThisFileDirectory)build\bin\</BaseOutputPath>
+    <BaseIntermediateOutputPath>$(MSBuildThisFileDirectory)build\obj\</BaseIntermediateOutputPath>
+</PropertyGroup>");
+
+            var result = await MSBuildProcessManager.DotnetMSBuild(project, args: "/restore");
+            Assert.BuildPassed(result);
+
+            var compressedFilesPath = Path.Combine(
+                project.DirectoryPath,
+                "build",
+                project.IntermediateOutputDirectory,
+                "compressed");
+
+            Assert.True(Directory.Exists(compressedFilesPath));
+        }
+
         private static GenerateBlazorBootJson.BootJsonData ReadBootJsonData(MSBuildResult result, string path)
         {
             return JsonSerializer.Deserialize<GenerateBlazorBootJson.BootJsonData>(

src/Components/WebAssembly/Build/test/BuildIntegrationTests/ProjectDirectory.cs

@@ -172,6 +172,20 @@ $@"<Project>
             File.WriteAllText(ProjectFilePath, updated);
         }
 
+        internal void AddDirectoryBuildContent(string content)
+        {
+            if (content == null)
+            {
+                throw new ArgumentNullException(nameof(content));
+            }
+
+            var filepath = Path.Combine(DirectoryPath, "Directory.Build.props");
+
+            var existing = File.ReadAllText(filepath);
+            var updated = existing.Replace("<!-- Test Placeholder -->", content);
+            File.WriteAllText(filepath, updated);
+        }
+
         public void Dispose()
         {
             if (PreserveWorkingDirectory)

src/Components/WebAssembly/Build/testassets/Directory.Build.props

@@ -1,6 +1,8 @@
 <Project>
     <Import Project="Before.Directory.Build.props" Condition="Exists('Before.Directory.Build.props')" />
 
+    <!-- Test Placeholder -->
+
     <PropertyGroup>
       <RepoRoot Condition="'$(RepoRoot)' ==''">$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), global.json))\</RepoRoot>
       <ComponentsRoot>$(RepoRoot)src\Components\</ComponentsRoot>