Refine the client-namespace-conflict diagnostic (#6161)

Fixes Azure/autorest.csharp#5241

I removed the report diagnostic in our emitter - because not every
generator would have this issue
and move the diagnostic reporting into our C# generator, when we build
the namespace for a client type.

I also added a few test cases for the `Emitter` class in our C#
generator, which leads to series of other changes about the disposing
issue.

packages/http-client-csharp/emitter/src/lib/client-model-builder.ts

@@ -92,20 +92,11 @@ export function createModel(sdkContext: CSharpEmitterContext): CodeModel {
     const uri = getMethodUri(endpointParameter);
     const clientParameters = fromSdkEndpointParameter(endpointParameter);
     const clientName = getClientName(client, parentNames);
-    // see if this namespace is a sub-namespace of an existing bad namespace
-    const segments = client.namespace.split(".");
-    const lastSegment = segments[segments.length - 1];
-    if (lastSegment === clientName) {
-      // we report diagnostics when the last segment of the namespace is the same as the client name
-      // because in our design, a sub namespace will be generated as a sub client with exact the same name as the namespace
-      // in csharp, this will cause a conflict between the namespace and the class name
-      sdkContext.logger.reportDiagnostic({
-        code: "client-namespace-conflict",
-        format: { namespace: client.namespace, clientName },
-        target: client.__raw.type ?? NoTarget,
-      });
-    }
 
+    sdkContext.__typeCache.crossLanguageDefinitionIds.set(
+      client.crossLanguageDefinitionId,
+      client.__raw.type,
+    );
     return {
       Name: clientName,
       Namespace: client.namespace,
@@ -125,6 +116,7 @@ export function createModel(sdkContext: CSharpEmitterContext): CodeModel {
       Parent: parentNames.length > 0 ? parentNames[parentNames.length - 1] : undefined,
       Parameters: clientParameters,
       Decorators: client.decorators,
+      CrossLanguageDefinitionId: client.crossLanguageDefinitionId,
     };
   }
 

packages/http-client-csharp/emitter/src/lib/lib.ts

@@ -63,7 +63,7 @@ const diags: { [code: string]: DiagnosticDefinition<DiagnosticMessages> } = {
   "client-namespace-conflict": {
     severity: "warning",
     messages: {
-      default: paramMessage`namespace ${"clientNamespace"} conflicts with client ${"clientName"}, please use @clientName to specify a different name for the client.`,
+      default: paramMessage`${"message"}`,
     },
   },
   "unsupported-endpoint-url": {

packages/http-client-csharp/emitter/src/lib/type-converter.ts

@@ -125,7 +125,7 @@ function updateSdkTypeReferences(
   if ("crossLanguageDefinitionId" in sdkType) {
     sdkContext.__typeCache.crossLanguageDefinitionIds.set(
       sdkType.crossLanguageDefinitionId,
-      sdkType,
+      sdkType.__raw,
     );
   }
 }

packages/http-client-csharp/emitter/src/lib/utils.ts

@@ -90,11 +90,7 @@ function processJsonRpc(context: CSharpEmitterContext, message: string) {
     if (crossLanguageDefinitionId === undefined) {
       return undefined;
     }
-    const target = context.__typeCache.crossLanguageDefinitionIds.get(crossLanguageDefinitionId);
-    if (target) {
-      return target.__raw;
-    }
-    return undefined;
+    return context.__typeCache.crossLanguageDefinitionIds.get(crossLanguageDefinitionId);
   }
 }
 

packages/http-client-csharp/emitter/src/sdk-context.ts

@@ -2,6 +2,7 @@
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 import { SdkContext, SdkType } from "@azure-tools/typespec-client-generator-core";
+import { Type } from "@typespec/compiler";
 import { Logger } from "./lib/logger.js";
 import { CSharpEmitterOptions } from "./options.js";
 import { InputEnumType, InputModelType, InputType } from "./type/input-type.js";
@@ -16,7 +17,7 @@ export interface CSharpEmitterContext extends SdkContext<CSharpEmitterOptions> {
 }
 
 export interface SdkTypeMap {
-  crossLanguageDefinitionIds: Map<string, SdkType>;
+  crossLanguageDefinitionIds: Map<string, Type | undefined>;
   types: Map<SdkType, InputType>;
   models: Map<string, InputModelType>;
   enums: Map<string, InputEnumType>;

packages/http-client-csharp/emitter/src/type/input-client.ts

@@ -16,4 +16,5 @@ export interface InputClient {
   Parent?: string;
   Parameters?: InputParameter[];
   Decorators?: DecoratorInfo[];
+  CrossLanguageDefinitionId: string;
 }

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

@@ -7,6 +7,7 @@
 using System.Linq;
 using System.Threading;
 using Microsoft.TypeSpec.Generator.ClientModel.Primitives;
+using Microsoft.TypeSpec.Generator.EmitterRpc;
 using Microsoft.TypeSpec.Generator.Expressions;
 using Microsoft.TypeSpec.Generator.Input;
 using Microsoft.TypeSpec.Generator.Primitives;
@@ -147,9 +148,29 @@ public ClientProvider(InputClient inputClient)
             _subClients = new(GetSubClients);
         }
 
-        protected override string BuildNamespace() => string.IsNullOrEmpty(_inputClient.Namespace) ?
-            base.BuildNamespace() :
-            ScmCodeModelPlugin.Instance.TypeFactory.GetCleanNameSpace(_inputClient.Namespace);
+        private const string namespaceConflictCode = "client-namespace-conflict";
+
+        private string? _namespace;
+        // This `BuildNamespace` method has been called twice - one when building the `Type`, the other is trying to find the CustomCodeView, both of them are required.
+        // therefore here to avoid this being called twice because this method now reports a diagnostic, we cache the result.
+        protected override string BuildNamespace() => _namespace ??= BuildNamespaceCore();
+
+        private string BuildNamespaceCore()
+        {
+            // if namespace is empty, we fallback to the root namespace
+            if (string.IsNullOrEmpty(_inputClient.Namespace))
+            {
+                return base.BuildNamespace();
+            }
+            var ns = ScmCodeModelPlugin.Instance.TypeFactory.GetCleanNameSpace(_inputClient.Namespace);
+
+            // figure out if this namespace has been changed for this client
+            if (!StringExtensions.IsLastNamespaceSegmentTheSame(ns, _inputClient.Namespace))
+            {
+                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;
+        }
 
         private IReadOnlyList<ParameterProvider> GetSubClientInternalConstructorParameters()
         {

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.Input/src/InputTypes/InputClient.cs

@@ -11,21 +11,23 @@ public class InputClient
         private readonly string? _key;
         private IReadOnlyDictionary<string, InputClientExample>? _examples;
 
-        public InputClient(string name, string @namespace, string? summary, string? doc, IReadOnlyList<InputOperation> operations, IReadOnlyList<InputParameter> parameters, string? parent)
+        public InputClient(string name, string @namespace, string crossLanguageDefinitionId, string? summary, string? doc, IReadOnlyList<InputOperation> operations, IReadOnlyList<InputParameter> parameters, string? parent)
         {
             Name = name;
             Namespace = @namespace;
+            CrossLanguageDefinitionId = crossLanguageDefinitionId;
             Summary = summary;
             Doc = doc;
             Operations = operations;
             Parameters = parameters;
             Parent = parent;
         }
 
-        public InputClient() : this(string.Empty, string.Empty, string.Empty, string.Empty, Array.Empty<InputOperation>(), Array.Empty<InputParameter>(), null) { }
+        public InputClient() : this(string.Empty, string.Empty, string.Empty, string.Empty, string.Empty, Array.Empty<InputOperation>(), Array.Empty<InputParameter>(), null) { }
 
         public string Name { get; internal set; }
         public string Namespace { get; internal set; }
+        public string CrossLanguageDefinitionId { get; internal set; }
         public string? Summary { get; internal set; }
         public string? Doc { get; internal set; }
         public IReadOnlyList<InputOperation> Operations { get; internal set; }

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.Input/src/InputTypes/Serialization/TypeSpecInputClientConverter.cs

@@ -23,7 +23,7 @@ public TypeSpecInputClientConverter(TypeSpecReferenceHandler referenceHandler)
         public override void Write(Utf8JsonWriter writer, InputClient value, JsonSerializerOptions options)
             => throw new NotSupportedException("Writing not supported");
 
-        private static InputClient? CreateInputClient(ref Utf8JsonReader reader, string? id, JsonSerializerOptions options, ReferenceResolver resolver)
+        private InputClient? CreateInputClient(ref Utf8JsonReader reader, string? id, JsonSerializerOptions options, ReferenceResolver resolver)
         {
             if (id == null)
             {
@@ -42,6 +42,7 @@ public override void Write(Utf8JsonWriter writer, InputClient value, JsonSeriali
             IReadOnlyList<InputParameter>? parameters = null;
             IReadOnlyList<InputDecoratorInfo>? decorators = null;
             string? parent = null;
+            string? crossLanguageDefinitionId = null;
 
             while (reader.TokenType != JsonTokenType.EndObject)
             {
@@ -52,7 +53,8 @@ public override void Write(Utf8JsonWriter writer, InputClient value, JsonSeriali
                     || reader.TryReadWithConverter(nameof(InputClient.Operations), options, ref operations)
                     || reader.TryReadWithConverter(nameof(InputClient.Parameters), options, ref parameters)
                     || reader.TryReadString(nameof(InputClient.Parent), ref parent)
-                    || reader.TryReadWithConverter(nameof(InputClient.Decorators), options, ref decorators);
+                    || reader.TryReadWithConverter(nameof(InputClient.Decorators), options, ref decorators)
+                    || reader.TryReadString("CrossLanguageDefinitionId", ref crossLanguageDefinitionId);
 
                 if (!isKnownProperty)
                 {
@@ -62,18 +64,18 @@ public override void Write(Utf8JsonWriter writer, InputClient value, JsonSeriali
 
             client.Name = name ?? throw new JsonException("InputClient must have name");
             client.Namespace = @namespace ?? string.Empty;
+            client.CrossLanguageDefinitionId = crossLanguageDefinitionId ?? string.Empty;
             client.Summary = summary;
             client.Doc = doc;
-            client.Operations = operations ?? Array.Empty<InputOperation>();
-            client.Parameters = parameters ?? Array.Empty<InputParameter>();
+            client.Operations = operations ?? [];
+            client.Parameters = parameters ?? [];
             client.Parent = parent;
             client.Decorators = decorators ?? [];
 
-            if (GetLastSegment(client.Namespace) == client.Name)
+            var lastSegment = GetLastSegment(client.Namespace);
+            if (lastSegment == client.Name)
             {
-                // invalid namespace segment found
-                // check if the list is already there
-                // get the list out
+                // invalid namespace segment found, add it into the list
                 var invalidNamespaceSegments = (List<string>)resolver.ResolveReference(TypeSpecSerialization.InvalidNamespaceSegmentsKey);
                 invalidNamespaceSegments.Add(client.Name);
             }

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

@@ -6,9 +6,6 @@
 using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
-using Microsoft.TypeSpec.Generator.EmitterRpc;
-using Microsoft.CodeAnalysis;
-using Microsoft.TypeSpec.Generator.Providers;
 using Microsoft.TypeSpec.Generator.SourceInput;
 
 namespace Microsoft.TypeSpec.Generator
@@ -88,7 +85,7 @@ 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 = new Emitter(Console.OpenStandardOutput());
         }
 
         // for mocking
@@ -58,6 +60,8 @@ protected CodeModelPlugin()
         internal bool IsNewProject { get; set; }
         private InputLibrary _inputLibrary;
 
+        public virtual Emitter Emitter { get; }
+
         // 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 StreamWriter _writer;
 
-        private Emitter()
+        internal Emitter(Stream stream)
         {
-            _writer = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = true };
+            _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/Providers/TypeProvider.cs

@@ -110,7 +110,7 @@ public string? Deprecated
         public CSharpType Type => _type ??=
             new(
                 _name ??= CustomCodeView?.Name ?? BuildName(),
-                CustomCodeView?.BuildNamespace() ?? BuildNamespace(),
+                CustomCodeView?.Type.Namespace ?? BuildNamespace(),
                 this is EnumProvider ||
                 DeclarationModifiers.HasFlag(TypeSignatureModifiers.Struct) ||
                 DeclarationModifiers.HasFlag(TypeSignatureModifiers.Enum),

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

@@ -244,5 +244,50 @@ public static string ToApiVersionMemberName(this string version)
 
             return CultureInfo.InvariantCulture.TextInfo.ToTitleCase(sb.ToString());
         }
+
+        /// <summary>
+        /// Checks if two namespaces share the same last segment
+        /// </summary>
+        /// <param name="left">the first namespace</param>
+        /// <param name="right">the second namespace</param>
+        /// <returns></returns>
+        public static bool IsLastNamespaceSegmentTheSame(string left, string right)
+        {
+            // finish this via Span API
+            var leftSpan = left.AsSpan();
+            var rightSpan = right.AsSpan();
+            // swap if left is longer, we ensure left is the shorter one
+            if (leftSpan.Length > rightSpan.Length)
+            {
+                var temp = leftSpan;
+                leftSpan = rightSpan;
+                rightSpan = temp;
+            }
+            for (int i = 1; i <= leftSpan.Length; i++)
+            {
+                var lc = leftSpan[^i];
+                var rc = rightSpan[^i];
+                // check if each char is the same from the right-most side
+                // if both of them are dot, we finished scanning the last segment - and if we could be here, meaning all of them are the same, return true.
+                if (lc == '.' && rc == '.')
+                {
+                    return true;
+                }
+                // if these are different - there is one different character, return false.
+                if (lc != rc)
+                {
+                    return false;
+                }
+            }
+
+            // we come here because we run out of characters in left - which means left does not have a dot.
+            // if they have the same length, they are identical, return true
+            if (leftSpan.Length == rightSpan.Length)
+            {
+                return true;
+            }
+            // otherwise, right is longer, we check its next character, if it is the dot, return true, otherwise return false.
+            return rightSpan[^(leftSpan.Length + 1)] == '.';
+        }
     }
 }

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

@@ -2,6 +2,7 @@
 // Licensed under the MIT License.
 
 using System.Threading.Tasks;
+using Microsoft.TypeSpec.Generator.EmitterRpc;
 
 namespace Microsoft.TypeSpec.Generator
 {

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

@@ -31,11 +31,9 @@ public static async Task<int> Main(string[] args)
 
         private static async Task<int> Run(CommandLineOptions options, GeneratorRunner runner)
         {
-            using var emitter = Emitter.Instance;
-
             if (options.ShouldDebug)
             {
-                emitter.Debug("Attempting to attach debugger..");
+                Console.Error.WriteLine("Attempting to attach debugger..");
                 Debugger.Launch();
             }
 
@@ -50,6 +48,8 @@ private static async Task<int> Run(CommandLineOptions options, GeneratorRunner r
                 return 1;
             }
 
+            (CodeModelPlugin.Instance.Emitter as IDisposable)?.Dispose();
+
             return 0;
         }
     }