[MSBUILD SDK] Add dotnet clean support

src/Azure.Functions.Sdk/Targets/Azure.Functions.Sdk.props

@@ -12,6 +12,7 @@ WARNING:  DO NOT MODIFY this file unless you are knowledgeable about MSBuild and
 <Project>
 
   <PropertyGroup>
+    <_WorkerConfigFileName>worker.config.json</_WorkerConfigFileName>
     <AzureFunctionsVersion>v4</AzureFunctionsVersion>
     <MSBuildFunctionsTargetsPath>$(MSBuildExtensionsPath)\Microsoft\VisualStudio\Managed.Functions\</MSBuildFunctionsTargetsPath>
   </PropertyGroup>

src/Azure.Functions.Sdk/Targets/Azure.Functions.Sdk.targets

@@ -16,6 +16,7 @@ WARNING:  DO NOT MODIFY this file unless you are knowledgeable about MSBuild and
   <UsingTask TaskName="$(AzureFunctionsTaskNamespace).GenerateWorkerConfig" AssemblyFile="$(AzureFunctionsSdkTasksAssembly)" />
 
   <PropertyGroup>
+    <_WorkerConfigOutputPath>$(IntermediateOutputPath)$(_WorkerConfigFileName)</_WorkerConfigOutputPath>
     <_AzureFunctionsVersionStandardized>$(AzureFunctionsVersion.ToLowerInvariant().Split('-')[0])</_AzureFunctionsVersionStandardized>
     <_FunctionsRuntimeMajorVersion>$(_AzureFunctionsVersionStandardized.TrimStart('vV'))</_FunctionsRuntimeMajorVersion>
     <_ToolingSuffix Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp'">net$([MSBuild]::GetTargetFrameworkVersion('$(TargetFramework)', 1))-isolated</_ToolingSuffix>
@@ -94,11 +95,6 @@ WARNING:  DO NOT MODIFY this file unless you are knowledgeable about MSBuild and
   </Target>
 
   <Target Name="_PreGenerateWorkerConfig" Returns="@(_WorkerConfig)">
-    <PropertyGroup>
-      <_WorkerConfigFileName>worker.config.json</_WorkerConfigFileName>
-      <_WorkerConfigOutputPath>$(IntermediateOutputPath)$(_WorkerConfigFileName)</_WorkerConfigOutputPath>
-    </PropertyGroup>
-
     <ItemGroup>
       <_WorkerConfig Include="$(_WorkerConfigOutputPath)" TargetPath="$(_WorkerConfigFileName)" />
     </ItemGroup>
@@ -136,4 +132,9 @@ WARNING:  DO NOT MODIFY this file unless you are knowledgeable about MSBuild and
     </ItemGroup>
   </Target>
 
+  <!-- Cleans intermediate worker.config.json that CoreClean does not track. -->
+  <Target Name="_CleanWorkerConfig" AfterTargets="CoreClean">
+    <Delete Files="$(_WorkerConfigOutputPath)" TreatErrorsAsWarnings="true" />
+  </Target>
+
 </Project>

src/Azure.Functions.Sdk/Targets/Extensions/Azure.Functions.Sdk.Extensions.targets

@@ -127,6 +127,21 @@ WARNING:  DO NOT MODIFY this file unless you are knowledgeable about MSBuild and
     </Copy>
   </Target>
 
+  <!--
+    Cleans Functions extension artifacts that CoreClean does not track:
+    the generated extension project directory, intermediate extensions.json,
+    and the .azurefunctions output directory.
+  -->
+  <Target Name="_CleanFunctionsExtensions" AfterTargets="CoreClean">
+    <ItemGroup>
+      <_FunctionsProjectDirToClean Include="@(_AzureFunctionsTargetFramework->'%(ProjectFile)')" />
+    </ItemGroup>
+    <RemoveDir Directories="@(_FunctionsProjectDirToClean->'%(RootDir)%(Directory)')" />
+    <Delete Files="$(_FunctionsIntermediateExtensionJsonPath)" TreatErrorsAsWarnings="true" />
+    <Delete Files="$(_FunctionsIntermediateExtensionJsonPath).hash" TreatErrorsAsWarnings="true" />
+    <RemoveDir Directories="$(TargetDir).azurefunctions" />
+  </Target>
+
   <!--
     Until there is a consistent post-restore hook which gives a guarantee to run our targets after restore,
     _VerifyRestoredFunctionsExtensions will verify the restore hook has run. If extension restore hook has not

test/Azure.Functions.Sdk.Tests/Integration/SdkEndToEndTests.Clean.cs

@@ -0,0 +1,85 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using Microsoft.Build.Utilities.ProjectCreation;
+
+namespace Azure.Functions.Sdk.Tests.Integration;
+
+public partial class SdkEndToEndTests
+{
+    [Fact]
+    public void Clean_RemovesFunctionsArtifacts()
+    {
+        // Arrange
+        ProjectCreator project = ProjectCreator.Templates.AzureFunctionsProject(
+            GetTempCsproj())
+            .Property("AssemblyName", "MyFunctionApp")
+            .WriteSourceFile("Program.cs", Resources.Program_Minimal_cs);
+
+        project.Build(restore: true).Should().BeSuccessful().And.HaveNoIssues();
+
+        string outputPath = project.GetOutputPath();
+        string intermediatePath = project.GetIntermediateOutputPath();
+        string extensionProjectDir = project.GetFunctionsExtensionProjectDirectory();
+
+        // Verify artifacts exist after build.
+        File.Exists(Path.Combine(outputPath, "worker.config.json")).Should().BeTrue("worker.config.json should exist in output after build");
+        File.Exists(Path.Combine(outputPath, "extensions.json")).Should().BeTrue("extensions.json should exist in output after build");
+        Directory.Exists(Path.Combine(outputPath, Constants.ExtensionsOutputFolder)).Should().BeTrue(".azurefunctions should exist in output after build");
+        File.Exists(Path.Combine(intermediatePath, "worker.config.json")).Should().BeTrue("worker.config.json should exist in intermediate after build");
+        File.Exists(Path.Combine(intermediatePath, "extensions.json")).Should().BeTrue("extensions.json should exist in intermediate after build");
+        File.Exists(Path.Combine(intermediatePath, "extensions.json.hash")).Should().BeTrue("extensions.json.hash should exist in intermediate after build");
+        Directory.Exists(extensionProjectDir).Should().BeTrue("extension project directory should exist after build");
+
+        // Act
+        BuildOutput cleanOutput = project.Clean();
+
+        // Assert
+        cleanOutput.Should().BeSuccessful();
+        File.Exists(Path.Combine(intermediatePath, "worker.config.json")).Should().BeFalse("worker.config.json should be cleaned from intermediate");
+        File.Exists(Path.Combine(intermediatePath, "extensions.json")).Should().BeFalse("extensions.json should be cleaned from intermediate");
+        File.Exists(Path.Combine(intermediatePath, "extensions.json.hash")).Should().BeFalse("extensions.json.hash should be cleaned from intermediate");
+        Directory.Exists(extensionProjectDir).Should().BeFalse("extension project directory should be cleaned");
+        Directory.Exists(Path.Combine(outputPath, Constants.ExtensionsOutputFolder)).Should().BeFalse(".azurefunctions should be cleaned from output");
+    }
+
+    [Fact]
+    public void Clean_MultiTarget_RemovesFunctionsArtifacts()
+    {
+        // Arrange
+        string[] targetFrameworks = ["net8.0", "net481"];
+        ProjectCreator project = ProjectCreator.Templates.AzureFunctionsProject(
+            GetTempCsproj(), targetFramework: null)
+            .TargetFrameworks(targetFrameworks)
+            .Property("AssemblyName", "MyFunctionApp")
+            .Property("LangVersion", "latest")
+            .WriteSourceFile("Program.cs", Resources.Program_Minimal_cs);
+
+        project.Build(restore: true).Should().BeSuccessful().And.HaveNoIssues();
+
+        // Verify artifacts exist for each TFM after build.
+        foreach (string tfm in targetFrameworks)
+        {
+            string outputPath = GetMultiTargetOutputPath(project, tfm);
+            string extensionProjectDir = project.GetFunctionsExtensionProjectDirectory(tfm);
+
+            File.Exists(Path.Combine(outputPath, "worker.config.json")).Should().BeTrue($"worker.config.json should exist in {tfm} output after build");
+            Directory.Exists(Path.Combine(outputPath, Constants.ExtensionsOutputFolder)).Should().BeTrue($".azurefunctions should exist in {tfm} output after build");
+            Directory.Exists(extensionProjectDir).Should().BeTrue($"extension project directory should exist for {tfm} after build");
+        }
+
+        // Act
+        BuildOutput cleanOutput = project.Clean();
+
+        // Assert
+        cleanOutput.Should().BeSuccessful();
+        foreach (string tfm in targetFrameworks)
+        {
+            string outputPath = GetMultiTargetOutputPath(project, tfm);
+            string extensionProjectDir = project.GetFunctionsExtensionProjectDirectory(tfm);
+
+            Directory.Exists(extensionProjectDir).Should().BeFalse($"extension project directory should be cleaned for {tfm}");
+            Directory.Exists(Path.Combine(outputPath, Constants.ExtensionsOutputFolder)).Should().BeFalse($".azurefunctions should be cleaned from {tfm} output");
+        }
+    }
+}

test/Azure.Functions.Sdk.Tests/ProjectCreatorExtensions.cs

@@ -205,6 +205,12 @@ public BuildOutput Publish(bool build = false, bool restore = false, IDictionary
             return output;
         }
 
+        public BuildOutput Clean(IDictionary<string, string>? globalProperties = null)
+        {
+            project.TryBuild("Clean", globalProperties, out _, out BuildOutput output);
+            return output;
+        }
+
         public TargetResult? RunTarget(string targetName, IDictionary<string, string>? globalProperties = null)
         {
             project.TryBuild(