Avoid all service-related codegen when AddServicesExtension=false

We were still emitting partial method implementations which caused build failures.

Adding that property effectively causes only the ServiceAttribute to be emitted.

Author: kzu

DependencyInjection.slnx

@@ -3,4 +3,5 @@
   <Project Path="src/CodeAnalysis.Tests/CodeAnalysis.Tests.csproj" />
   <Project Path="src/DependencyInjection.Tests/DependencyInjection.Tests.csproj" />
   <Project Path="src/DependencyInjection/DependencyInjection.csproj" />
+  <Project Path="src/NoAddServices/NoAddServices.csproj" />
 </Solution>

src/CodeAnalysis.Tests/AddServicesAnalyzerTests.cs

@@ -1,11 +1,7 @@
-using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
+using System.Collections.Immutable;
 using System.IO;
-using System.Linq;
 using System.Threading.Tasks;
 using Devlooped.Extensions.DependencyInjection;
-using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Testing;
 using Microsoft.CodeAnalysis.Testing;
 using Xunit;

src/DependencyInjection/IncrementalGenerator.cs

@@ -339,6 +339,9 @@ void ReportInconsistencies(SourceProductionContext context, ImmutableArray<Servi
 
     void AddPartial(string methodName, SourceProductionContext ctx, (ImmutableArray<KeyedService> Types, Compilation Compilation) data)
     {
+        if (data.Types.IsEmpty)
+            return;
+
         var builder = new StringBuilder()
             .AppendLine("// <auto-generated />");
 

src/NoAddServices/NoAddServices.csproj

@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <Import Project="..\DependencyInjection\Devlooped.Extensions.DependencyInjection.props" />
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
+    <!-- This property causes no AddXXX partial methods to be emitted -->
+    <AddServicesExtension>false</AddServicesExtension>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="10.0.1" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\DependencyInjection\DependencyInjection.csproj" ReferenceOutputAssembly="false" OutputItemType="Analyzer" />
+  </ItemGroup>
+
+  <Import Project="..\DependencyInjection\Devlooped.Extensions.DependencyInjection.targets" />
+
+</Project>