refactor where the emitter located and resolve the disposing issue

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/src/Providers/ClientProvider.cs

@@ -165,7 +165,7 @@ private string BuildNamespaceCore()
             // figure out if this namespace has been changed for this client
             if (!StringExtensions.IsLastNamespaceSegmentTheSame(ns, _inputClient.Namespace))
             {
-                Emitter.Instance.ReportDiagnostic(namespaceConflictCode, $"namespace {_inputClient.Namespace} conflicts with client {_inputClient.Name}, please use `@clientName` to specify a different name for the client.", _inputClient.CrossLanguageDefinitionId);
+                ScmCodeModelPlugin.Instance.Emitter.ReportDiagnostic(namespaceConflictCode, $"namespace {_inputClient.Namespace} conflicts with client {_inputClient.Name}, please use `@clientName` to specify a different name for the client.", _inputClient.CrossLanguageDefinitionId);
             }
             return ns;
         }

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator/perf/PluginInitializer.cs

@@ -11,7 +11,7 @@ internal static class PluginInitializer
         public static void Initialize()
         {
             PluginHandler pluginHandler = new PluginHandler();
-            pluginHandler.LoadPlugin(new CommandLineOptions
+            pluginHandler.LoadPlugin(null!, new CommandLineOptions
             {
                 OutputDirectory = Path.Combine(Directory.GetParent(Assembly.GetExecutingAssembly().Location)!.FullName, "Projects", "Model"),
                 PluginName = "CodeModelPlugin"

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator/src/CSharpGen.cs

@@ -6,7 +6,6 @@
 using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
-using Microsoft.TypeSpec.Generator.EmitterRpc;
 using Microsoft.TypeSpec.Generator.SourceInput;
 
 namespace Microsoft.TypeSpec.Generator
@@ -85,7 +84,7 @@ public async Task ExecuteAsync()
                     continue;
                 }
                 var filename = Path.Combine(outputPath, file.Name);
-                Emitter.Instance.Info($"Writing {Path.GetFullPath(filename)}");
+                CodeModelPlugin.Instance.Emitter.Info($"Writing {Path.GetFullPath(filename)}");
                 Directory.CreateDirectory(Path.GetDirectoryName(filename)!);
                 await File.WriteAllTextAsync(filename, file.Text);
             }

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator/src/CodeModelPlugin.cs

@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.ComponentModel.Composition;
 using Microsoft.CodeAnalysis;
+using Microsoft.TypeSpec.Generator.EmitterRpc;
 using Microsoft.TypeSpec.Generator.Input;
 using Microsoft.TypeSpec.Generator.Primitives;
 using Microsoft.TypeSpec.Generator.Providers;
@@ -46,6 +47,7 @@ public CodeModelPlugin(GeneratorContext context)
             Configuration = context.Configuration;
             _inputLibrary = new InputLibrary(Configuration.OutputDirectory);
             TypeFactory = new TypeFactory();
+            Emitter = null!;
         }
 
         // for mocking
@@ -58,6 +60,8 @@ protected CodeModelPlugin()
         internal bool IsNewProject { get; set; }
         private InputLibrary _inputLibrary;
 
+        public virtual Emitter Emitter { get; internal set; }
+
         // Extensibility points to be implemented by a plugin
         public virtual TypeFactory TypeFactory { get; }
 

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator/src/EmitterRpc/Emitter.cs

@@ -13,18 +13,15 @@ public sealed class Emitter : IDisposable
         private const string Trace = "trace";
         private const string Diagnostic = "diagnostic";
 
-        private static Emitter? _emitter;
         private bool _disposed;
 
-        private readonly TextWriter _writer;
+        private readonly StreamWriter _writer;
 
-        internal Emitter()
+        internal Emitter(Stream stream)
         {
-            _writer = Console.Out;
+            _writer = new StreamWriter(stream) { AutoFlush = true };
         }
 
-        public static Emitter Instance => _emitter ??= new Emitter();
-
         private void SendNotification(string method, object content)
         {
             var paramsContent = JsonSerializer.Serialize(content);

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator/src/StartUp/GeneratorRunner.cs

@@ -2,15 +2,16 @@
 // Licensed under the MIT License.
 
 using System.Threading.Tasks;
+using Microsoft.TypeSpec.Generator.EmitterRpc;
 
 namespace Microsoft.TypeSpec.Generator
 {
     internal class GeneratorRunner
     {
-        public async Task RunAsync(CommandLineOptions options)
+        public async Task RunAsync(Emitter emitter, CommandLineOptions options)
         {
             PluginHandler pluginHandler = new();
-            pluginHandler.LoadPlugin(options);
+            pluginHandler.LoadPlugin(emitter, options);
 
             var csharpGen = new CSharpGen();
             await csharpGen.ExecuteAsync();

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator/src/StartUp/PluginHandler.cs

@@ -5,23 +5,24 @@
 using System.Collections.Generic;
 using System.ComponentModel.Composition;
 using System.ComponentModel.Composition.Hosting;
+using Microsoft.TypeSpec.Generator.EmitterRpc;
 
 namespace Microsoft.TypeSpec.Generator
 {
     internal class PluginHandler
     {
-        public void LoadPlugin(CommandLineOptions options)
+        public void LoadPlugin(Emitter emitter, CommandLineOptions options)
         {
             using DirectoryCatalog directoryCatalog = new(AppContext.BaseDirectory);
             using CompositionContainer container = new(directoryCatalog);
 
             container.ComposeExportedValue(new GeneratorContext(Configuration.Load(options.OutputDirectory)));
             container.ComposeParts(this);
 
-            SelectPlugin(options);
+            SelectPlugin(emitter, options);
         }
 
-        internal void SelectPlugin(CommandLineOptions options)
+        internal void SelectPlugin(Emitter emitter, CommandLineOptions options)
         {
             bool loaded = false;
             foreach (var plugin in Plugins!)
@@ -30,6 +31,7 @@ internal void SelectPlugin(CommandLineOptions options)
                 {
                     CodeModelPlugin.Instance = plugin.Value;
                     CodeModelPlugin.Instance.IsNewProject = options.IsNewProject;
+                    CodeModelPlugin.Instance.Emitter = emitter;
                     loaded = true;
                     CodeModelPlugin.Instance.Configure();
                     break;

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator/src/StartUp/Program.cs

@@ -31,7 +31,7 @@ public static async Task<int> Main(string[] args)
 
         private static async Task<int> Run(CommandLineOptions options, GeneratorRunner runner)
         {
-            using var emitter = Emitter.Instance;
+            using var emitter = new Emitter(Console.OpenStandardOutput());
 
             if (options.ShouldDebug)
             {
@@ -41,7 +41,7 @@ private static async Task<int> Run(CommandLineOptions options, GeneratorRunner r
 
             try
             {
-                await runner.RunAsync(options);
+                await runner.RunAsync(emitter, options);
             }
             catch (Exception e)
             {

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator/test/EmitterRpc/EmitterTests.cs

@@ -10,7 +10,7 @@ namespace Microsoft.TypeSpec.Generator.Tests.EmitterRpc
 {
     public class EmitterTests
     {
-        private StringWriter? _stream;
+        private MemoryStream? _stream;
         private Emitter? _emitter;
 
         public EmitterTests()
@@ -20,9 +20,8 @@ public EmitterTests()
         [SetUp]
         public void Setup()
         {
-            _stream = new StringWriter();
-            Console.SetOut(_stream);
-            _emitter = new Emitter();
+            _stream = new MemoryStream();
+            _emitter = new Emitter(_stream);
         }
 
         [TearDown]
@@ -37,35 +36,43 @@ public void TestInfo()
         {
             _emitter?.Info("Test message");
 
-            Assert.AreEqual(@"{""method"":""trace"",""params"":{""level"":""info"",""message"":""Test message""}}", _stream?.ToString().TrimEnd());
+            Assert.AreEqual(@"{""method"":""trace"",""params"":{""level"":""info"",""message"":""Test message""}}", GetResult());
         }
 
         [TestCase]
         public void TestDebug()
         {
             _emitter?.Debug("Test message");
-            Assert.AreEqual(@"{""method"":""trace"",""params"":{""level"":""debug"",""message"":""Test message""}}", _stream?.ToString().TrimEnd());
+
+            Assert.AreEqual(@"{""method"":""trace"",""params"":{""level"":""debug"",""message"":""Test message""}}", GetResult());
         }
 
         [TestCase]
         public void TestVerbose()
         {
             _emitter?.Verbose("Test message");
-            Assert.AreEqual(@"{""method"":""trace"",""params"":{""level"":""verbose"",""message"":""Test message""}}", _stream?.ToString().TrimEnd());
+            Assert.AreEqual(@"{""method"":""trace"",""params"":{""level"":""verbose"",""message"":""Test message""}}", GetResult());
         }
 
         [TestCase]
         public void TestReportDiagnosticWithTarget()
         {
             _emitter?.ReportDiagnostic("test-code", "Test message", "Test target");
-            Assert.AreEqual(@"{""method"":""diagnostic"",""params"":{""code"":""test-code"",""message"":""Test message"",""crossLanguageDefinitionId"":""Test target""}}", _stream?.ToString().TrimEnd());
+            Assert.AreEqual(@"{""method"":""diagnostic"",""params"":{""code"":""test-code"",""message"":""Test message"",""crossLanguageDefinitionId"":""Test target""}}", GetResult());
         }
 
         [TestCase]
         public void TestReportDiagnosticWithoutTarget()
         {
             _emitter?.ReportDiagnostic("test-code", "Test message");
-            Assert.AreEqual(@"{""method"":""diagnostic"",""params"":{""code"":""test-code"",""message"":""Test message""}}", _stream?.ToString().TrimEnd());
+            Assert.AreEqual(@"{""method"":""diagnostic"",""params"":{""code"":""test-code"",""message"":""Test message""}}", GetResult());
+        }
+
+        private string GetResult()
+        {
+            _stream?.Seek(0, SeekOrigin.Begin);
+            using var reader = new StreamReader(_stream!);
+            return reader.ReadToEnd().TrimEnd();
         }
     }
 }

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator/test/StartUp/PluginHandlerTests.cs

@@ -23,7 +23,7 @@ public void SelectPluginFindsMatchingPlugin()
             };
             CommandLineOptions options = new() { PluginName = "MockPlugin" };
 
-            Assert.DoesNotThrow(() => pluginHandler.SelectPlugin(options));
+            Assert.DoesNotThrow(() => pluginHandler.SelectPlugin(null!, options));
             mockPlugin.Verify(p => p.Configure(), Times.Once);
         }
 
@@ -41,7 +41,7 @@ public void SelectPluginThrowsWhenNoMatch()
             };
             CommandLineOptions options = new() { PluginName = "NonExistentPlugin" };
 
-            Assert.Throws<System.InvalidOperationException>(() => pluginHandler.SelectPlugin(options));
+            Assert.Throws<System.InvalidOperationException>(() => pluginHandler.SelectPlugin(null!, options));
             mockPlugin.Verify(p => p.Configure(), Times.Never);
         }
     }

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator/test/TestHelpers/MockHelpers.cs

@@ -6,6 +6,7 @@
 using System.IO;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis;
+using Microsoft.TypeSpec.Generator.EmitterRpc;
 using Microsoft.TypeSpec.Generator.Input;
 using Microsoft.TypeSpec.Generator.Primitives;
 using Microsoft.TypeSpec.Generator.Providers;
@@ -69,6 +70,8 @@ public static Mock<CodeModelPlugin> LoadMockPlugin(
             // initialize the singleton instance of the plugin
             var mockPlugin = new Mock<CodeModelPlugin>(new GeneratorContext(Configuration.Load(configFilePath, configuration))) { CallBase = true };
 
+            mockPlugin.Setup(p => p.Emitter).Returns(new Emitter(Console.OpenStandardOutput()));
+
             var mockTypeFactory = new Mock<TypeFactory>() { CallBase = true };
 
             if (createCSharpTypeCore != null)