Fix numeric suffix added to interface method names in ByTag mode

src/Refitter.Core/IdentifierUtils.cs

@@ -41,7 +41,10 @@ public static string Sanitize(this string value)
     {
         const char dash = '-';
 
-        // @ can be used and still make valid methode names. but this should make most use cases safe
+        if (string.IsNullOrEmpty(value))
+            return value;
+
+        // @ can be used and still make valid method names. but this should make most use cases safe
         if (
             (value.First() < 'A' || value.First() > 'Z') &&
             (value.First() < 'a' || value.First() > 'z') &&

src/Refitter.Core/OperationNameGenerator.cs

@@ -50,7 +50,7 @@ public OperationNameGenerator(OpenApiDocument document, RefitGeneratorSettings s
     }
 
     [ExcludeFromCodeCoverage]
-    public bool SupportsMultipleClients => throw new System.NotImplementedException();
+    public bool SupportsMultipleClients => defaultGenerator.SupportsMultipleClients;
 
     [ExcludeFromCodeCoverage]
     public string GetClientName(OpenApiDocument document, string path, string httpMethod, OpenApiOperation operation)

src/Refitter.Core/RefitGenerator.cs

@@ -114,6 +114,19 @@
         var factory = new CSharpClientGeneratorFactory(settings, document);
         var generator = factory.Create();
         var docGenerator = new XmlDocumentationGenerator(settings);
+
+        // Create the interface generator before calling GenerateFile() so that
+        // OperationNameGenerator.CheckForDuplicateOperationIds() sees the original
+        // (pre-generation) operation IDs. GenerateFile() auto-populates operation IDs
+        // with globally unique names which would prevent the switch to the path segments
+        // generator, causing unnecessary numeric suffixes in ByTag mode.
+        IRefitInterfaceGenerator interfaceGenerator = settings.MultipleInterfaces switch
+        {
+            MultipleInterfaces.ByEndpoint => new RefitMultipleInterfaceGenerator(settings, document, generator, docGenerator),
+            MultipleInterfaces.ByTag => new RefitMultipleInterfaceByTagGenerator(settings, document, generator, docGenerator),
+            _ => new RefitInterfaceGenerator(settings, document, generator, docGenerator),
+        };
+
         var contracts = generator.GenerateFile();
         contracts = SanitizeGeneratedContracts(contracts);
 
@@ -126,13 +139,6 @@
                     (current, import) => current.Replace($"{import}.", string.Empty));
         }
 
-        IRefitInterfaceGenerator interfaceGenerator = settings.MultipleInterfaces switch
-        {
-            MultipleInterfaces.ByEndpoint => new RefitMultipleInterfaceGenerator(settings, document, generator, docGenerator),
-            MultipleInterfaces.ByTag => new RefitMultipleInterfaceByTagGenerator(settings, document, generator, docGenerator),
-            _ => new RefitInterfaceGenerator(settings, document, generator, docGenerator),
-        };
-
         var refitInterfaces = GenerateClient(interfaceGenerator);
         var interfaceNames = refitInterfaces.Select(c => c.TypeName).ToArray();
         var refitInterfacesCode = string.Join("", refitInterfaces.Select(c => c.Content));
@@ -152,7 +158,7 @@
     }
 
     /// <summary>
     /// Generates multiple files containing Refit interfaces and contracts.
     /// </summary>
     /// <returns>A GeneratorOutput containing all generated code files.</returns>
     public GeneratorOutput GenerateMultipleFiles()
@@ -160,9 +166,12 @@
         var factory = new CSharpClientGeneratorFactory(settings, document);
         var generator = factory.Create();
         var docGenerator = new XmlDocumentationGenerator(settings);
-        var contracts = generator.GenerateFile();
-        contracts = SanitizeGeneratedContracts(contracts);
 
+        // Create the interface generator before calling GenerateFile() so that
+        // OperationNameGenerator.CheckForDuplicateOperationIds() sees the original
+        // (pre-generation) operation IDs. GenerateFile() auto-populates operation IDs
+        // with globally unique names which would prevent the switch to the path segments
+        // generator, causing unnecessary numeric suffixes in ByTag mode.
         IRefitInterfaceGenerator interfaceGenerator = settings.MultipleInterfaces switch
         {
             MultipleInterfaces.ByEndpoint
@@ -172,6 +181,9 @@
             _ => new RefitInterfaceGenerator(settings, document, generator, docGenerator),
         };
 
+        var contracts = generator.GenerateFile();
+        contracts = SanitizeGeneratedContracts(contracts);
+
         var generatedFiles = new List<GeneratedCode>();
 
         var refitInterfaces = GenerateClient(interfaceGenerator);
@@ -217,7 +229,7 @@
 
         const string pattern = @"^\s*\[(System\.Text\.Json\.Serialization\.)?JsonConverter\(typeof\((System\.Text\.Json\.Serialization\.)?JsonStringEnumConverter\)\)\]\s*$";
         var lines = contracts.Split(["\r\n", "\r", "\n"], StringSplitOptions.None);
         var filteredLines = lines
             .Where(
                 line => !Regex.IsMatch(
                     line,

src/Refitter.Core/RefitInterfaceGenerator.cs

@@ -45,6 +45,7 @@ private string GenerateInterfaceBody(out string? dynamicQuerystringParameters)
     {
         var code = new StringBuilder();
         var dynamicQuerystringParametersCodeBuilder = new StringBuilder();
+        var knownIdentifiers = new HashSet<string>();
         foreach (var kv in document.Paths)
         {
             foreach (var operations in kv.Value)
@@ -58,7 +59,8 @@ private string GenerateInterfaceBody(out string? dynamicQuerystringParameters)
 
                 var returnType = GetTypeName(operation);
                 var verb = operations.Key.CapitalizeFirstCharacter();
-                var operationName = GenerateOperationName(kv.Key, verb, operation);
+                var operationName = IdentifierUtils.Counted(knownIdentifiers, GenerateOperationName(kv.Key, verb, operation));
+                knownIdentifiers.Add(operationName);
                 var dynamicQuerystringParameterType = operationName + "QueryParams";
 
                 var operationModel = generator.CreateOperationModel(operation);

src/Refitter.Core/RefitMultipleInterfaceByTagGenerator.cs

@@ -45,7 +45,7 @@ public override IEnumerable<GeneratedCode> GenerateCode()
                 var returnType = GetTypeName(operation);
                 var verb = operations.Key.CapitalizeFirstCharacter();
 
-                string interfaceName = null!;
+                string interfaceName;
                 if (!interfacesByGroup.TryGetValue(kv.Key, out var sb))
                 {
                     interfacesByGroup[kv.Key] = sb = new StringBuilder();
@@ -59,6 +59,10 @@ public override IEnumerable<GeneratedCode> GenerateCode()
 
                     interfacesNamesByGroup[kv.Key] = interfaceName;
                 }
+                else
+                {
+                    interfaceName = interfacesNamesByGroup[kv.Key];
+                }
 
                 var operationName = GetOperationName(interfaceName, op.PathItem.Key, operations.Key, operation);
                 var dynamicQuerystringParameterType = operationName + "QueryParams";

src/Refitter.Tests/Examples/MultipleInterfacesByTagsWithSamePathSegmentTests.cs

@@ -0,0 +1,125 @@
+using FluentAssertions;
+using Refitter.Core;
+using Refitter.Tests.Build;
+using Refitter.Tests.TestUtilities;
+using TUnit.Core;
+
+namespace Refitter.Tests.Examples;
+
+/// <summary>
+/// Regression tests for https://github.com/christianhelle/refitter/issues/361
+/// When using ByTag, method names should not have numeric suffixes added for
+/// cross-interface uniqueness - deduplication should be per-interface.
+/// </summary>
+public class MultipleInterfacesByTagsWithSamePathSegmentTests
+{
+    private const string OpenApiSpec = @"
+openapi: '3.0.0'
+info:
+  title: 'Test API'
+  version: '1.0'
+paths:
+  /api/manage/2fa:
+    post:
+      tags:
+      - 'Manage'
+      responses:
+        '200':
+          description: 'ok'
+  /api/manage/info:
+    get:
+      tags:
+      - 'Manage'
+      responses:
+        '200':
+          description: 'ok'
+    post:
+      tags:
+      - 'Manage'
+      responses:
+        '200':
+          description: 'ok'
+  /api/account/info:
+    get:
+      tags:
+      - 'Account'
+      responses:
+        '200':
+          description: 'ok'
+  /api/user/info:
+    get:
+      tags:
+      - 'User'
+      responses:
+        '200':
+          description: 'ok'
+";
+
+    [Test]
+    public async Task Can_Generate_Code()
+    {
+        string generatedCode = await GenerateCode();
+        generatedCode.Should().NotBeNullOrWhiteSpace();
+    }
+
+    [Test]
+    public async Task Generates_Manage_Interface()
+    {
+        string generatedCode = await GenerateCode();
+        generatedCode.Should().Contain("partial interface IManageApi");
+    }
+
+    [Test]
+    public async Task Generates_Account_Interface()
+    {
+        string generatedCode = await GenerateCode();
+        generatedCode.Should().Contain("partial interface IAccountApi");
+    }
+
+    [Test]
+    public async Task Generates_User_Interface()
+    {
+        string generatedCode = await GenerateCode();
+        generatedCode.Should().Contain("partial interface IUserApi");
+    }
+
+    [Test]
+    public async Task Account_Interface_Does_Not_Have_Numeric_Suffix()
+    {
+        string generatedCode = await GenerateCode();
+        // IAccountApi's GET /api/account/info should not get a numeric suffix
+        // even though IManageApi also has a GET /api/manage/info operation
+        generatedCode.Should().NotContainAny("Info2(", "Info3(", "InfoGet2(", "InfoGet3(", "InfoGET2(", "InfoGET3(");
+    }
+
+    [Test]
+    public async Task User_Interface_Does_Not_Have_Numeric_Suffix()
+    {
+        string generatedCode = await GenerateCode();
+        // IUserApi's GET /api/user/info should not get a numeric suffix
+        generatedCode.Should().NotContainAny("Info2(", "Info3(", "InfoGet2(", "InfoGet3(", "InfoGET2(", "InfoGET3(");
+    }
+
+    [Test]
+    public async Task Can_Build_Generated_Code()
+    {
+        string generatedCode = await GenerateCode();
+        BuildHelper
+            .BuildCSharp(generatedCode)
+            .Should()
+            .BeTrue();
+    }
+
+    private static async Task<string> GenerateCode()
+    {
+        var swaggerFile = await SwaggerFileHelper.CreateSwaggerFile(OpenApiSpec);
+        var settings = new RefitGeneratorSettings
+        {
+            OpenApiPath = swaggerFile,
+            MultipleInterfaces = MultipleInterfaces.ByTag,
+        };
+
+        var sut = await RefitGenerator.CreateAsync(settings);
+        return sut.Generate();
+    }
+}