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" Id="b96e7987-cd29-4648-920c-ef6e2830eb3f" />
 </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;
@@ -150,6 +146,59 @@ public static void Main()
         await test.RunAsync();
     }
 
+    [Fact]
+    public async Task NoServicesAddedIfFalse()
+    {
+        var test = new AnalyzerTest
+        {
+            TestCode = """
+            using System;
+            using Microsoft.Extensions.DependencyInjection;
+            
+            public record Command;
+            
+            public static class Program
+            {
+                public static void Main()
+                {
+                    var services = new ServiceCollection();
+                    {|#0:services.AddSingleton(new Command())|};
+                }
+            }
+            """,
+            TestState =
+            {
+                AnalyzerConfigFiles =
+                {
+                    ("/.editorconfig",
+                    """
+                    is_global = true
+                    build_property.AddServicesExtension = false
+                    """)
+                },
+                Sources =
+                {
+                    ThisAssembly.Resources.AddServicesNoReflectionExtension.Text,
+                    ThisAssembly.Resources.ServiceAttribute.Text,
+                    ThisAssembly.Resources.ServiceAttribute_1.Text
+                },
+                ReferenceAssemblies = new ReferenceAssemblies(
+                    "net8.0",
+                    new PackageIdentity(
+                        "Microsoft.NETCore.App.Ref", "8.0.0"),
+                        Path.Combine("ref", "net8.0"))
+                    .AddPackages(ImmutableArray.Create(
+                        new PackageIdentity("Microsoft.Extensions.DependencyInjection", "8.0.0")))
+            },
+        }.WithPreprocessorSymbols();
+
+        var expected = Verifier.Diagnostic(AddServicesAnalyzer.NoAddServicesCall).WithLocation(0);
+        test.ExpectedDiagnostics.Add(expected);
+
+        await test.RunAsync();
+    }
+
+
     [Fact]
     public async Task WarnIfAddServicesMissingMultipleLocations()
     {

src/DependencyInjection.Tests/DependencyInjection.Tests.csproj

@@ -6,6 +6,7 @@
     <TargetFramework>net10.0</TargetFramework>
     <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
     <RootNamespace>Tests</RootNamespace>
+    <!--<AddServicesExtension>false</AddServicesExtension>-->
   </PropertyGroup>
 
   <ItemGroup>

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>