Harden .refitter settings deserialization and output path handling

.gitignore

@@ -285,3 +285,6 @@ install.sh
 
 # Confidential temporary files — must not reach public repository
 tmp/
+test/Generated/GeneratedCode/*.generated.cs
+test/MSBuild/Generated/**/*.generated.cs
+test/MSBuild/GeneratedOutput/**/*.cs

src/Refitter.MSBuild/RefitterGenerateTask.cs

@@ -209,17 +209,12 @@ private List<string> GetExpectedGeneratedFiles(string refitterFilePath)
             else
             {
                 // Single file mode
-                string outputPath;
-                if (!string.IsNullOrWhiteSpace(outputFolder))
-                {
-                    // outputFolder is specified
-                    outputPath = Path.GetFullPath(Path.Combine(refitterFileDirectory, outputFolder, outputFilename));
-                }
-                else
-                {
-                    // No outputFolder specified - generate in current directory (default behavior)
-                    outputPath = Path.GetFullPath(Path.Combine(refitterFileDirectory, outputFilename));
-                }
+                // If outputFolder is not specified in .refitter, CLI uses default "./Generated"
+                var effectiveOutputFolder = !string.IsNullOrWhiteSpace(outputFolder)
+                    ? outputFolder
+                    : "./Generated";
+
+                var outputPath = Path.GetFullPath(Path.Combine(refitterFileDirectory, effectiveOutputFolder, outputFilename));
                 generatedFiles.Add(outputPath);
             }
 

src/Refitter.Tests/Examples/PropertyNamingPolicyTests.cs

@@ -319,4 +319,4 @@ private static async Task<string> GenerateCodeFromSpec(
             }
         }
     }
-}
+}

src/Refitter.Tests/Examples/SettingsFileOutputPathTests.cs

@@ -0,0 +1,186 @@
+using System.Reflection;
+using FluentAssertions;
+using Refitter.Core;
+using Refitter.Tests.Build;
+
+namespace Refitter.Tests.Examples;
+
+/// <summary>
+/// Regression tests for issue #998: MSBuild + .NET 10 ignores outputFolder and filename-from-.refitter behavior
+/// Tests exercise the actual GenerateCommand helper logic via reflection
+/// </summary>
+public class SettingsFileOutputPathTests
+{
+    private const string MinimalOpenApiSpec = """
+        {
+          "openapi": "3.0.1",
+          "info": { "title": "Test API", "version": "1.0.0" },
+          "paths": {
+            "/test": {
+              "get": {
+                "operationId": "getTest",
+                "responses": {
+                  "200": {
+                    "description": "Success",
+                    "content": {
+                      "application/json": {
+                        "schema": {
+                          "type": "object",
+                          "properties": { "id": { "type": "integer" } }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+        """;
+
+    [Test]
+    public void SettingsFile_WithoutOutputFilename_UsesRefitterFilenameFallback()
+    {
+        var tempDir = CreateTempDirectory();
+
+        try
+        {
+            var settingsFile = Path.Combine(tempDir, "myapi.refitter");
+            File.WriteAllText(settingsFile, "{}");
+
+            var settingsJson = """
+                {
+                  "openApiPath": "spec.json",
+                  "namespace": "TestNamespace"
+                }
+                """;
+
+            var refitGeneratorSettings = Serializer.Deserialize<RefitGeneratorSettings>(settingsJson);
+            var settings = new Settings { SettingsFilePath = settingsFile };
+
+            ApplySettingsFileDefaults(settingsFile, refitGeneratorSettings);
+
+            refitGeneratorSettings.OutputFilename.Should().Be("myapi.cs",
+                "because OutputFilename should default to the .refitter filename");
+
+            var outputPath = GetOutputPath(settings, refitGeneratorSettings);
+            Path.GetFullPath(outputPath).Should().Be(Path.GetFullPath(Path.Combine(tempDir, "Generated", "myapi.cs")),
+                "because default output folder is ./Generated rooted at the settings file directory");
+        }
+        finally
+        {
+            CleanupDirectory(tempDir);
+        }
+    }
+
+    [Test]
+    public void SettingsFile_WithExplicitDefaultOutputFolder_RootsToSettingsFileDirectory()
+    {
+        var tempDir = CreateTempDirectory();
+
+        try
+        {
+            var settingsFile = Path.Combine(tempDir, "api.refitter");
+            File.WriteAllText(settingsFile, "{}");
+
+            var settingsJson = """
+                {
+                  "openApiPath": "spec.json",
+                  "namespace": "TestNamespace",
+                  "outputFolder": "./Generated",
+                  "outputFilename": "Api.cs"
+                }
+                """;
+
+            var refitGeneratorSettings = Serializer.Deserialize<RefitGeneratorSettings>(settingsJson);
+            var settings = new Settings { SettingsFilePath = settingsFile };
+
+            ApplySettingsFileDefaults(settingsFile, refitGeneratorSettings);
+
+            var outputPath = GetOutputPath(settings, refitGeneratorSettings);
+            Path.GetFullPath(outputPath).Should().Be(Path.GetFullPath(Path.Combine(tempDir, "Generated", "Api.cs")),
+                "because outputFolder is rooted relative to the .refitter file directory");
+        }
+        finally
+        {
+            CleanupDirectory(tempDir);
+        }
+    }
+
+    [Test]
+    public async Task SettingsFile_PreservesNamingInterfaceName()
+    {
+        // Arrange: .refitter with custom naming.interfaceName
+        var tempDir = CreateTempDirectory();
+
+        try
+        {
+            var openApiFile = Path.Combine(tempDir, "spec.json");
+            await File.WriteAllTextAsync(openApiFile, MinimalOpenApiSpec);
+
+            var settingsJson = """
+                {
+                  "openApiPath": "spec.json",
+                  "namespace": "TestNamespace",
+                  "naming": {
+                    "useOpenApiTitle": false,
+                    "interfaceName": "CustomApi"
+                  }
+                }
+                """;
+
+            var refitGeneratorSettings = Serializer.Deserialize<RefitGeneratorSettings>(settingsJson);
+            refitGeneratorSettings.OpenApiPath = openApiFile;
+
+            var generator = await RefitGenerator.CreateAsync(refitGeneratorSettings);
+            var code = generator.Generate();
+
+            // Assert: Naming settings should be preserved and used in generation
+            refitGeneratorSettings.Naming.Should().NotBeNull();
+            refitGeneratorSettings.Naming.InterfaceName.Should().Be("CustomApi");
+            code.Should().Contain("interface ICustomApi", "because custom interface name should be used");
+            BuildHelper.BuildCSharp(code).Should().BeTrue();
+        }
+        finally
+        {
+            CleanupDirectory(tempDir);
+        }
+    }
+
+    private static string GetOutputPath(Settings settings, RefitGeneratorSettings refitGeneratorSettings)
+    {
+        var method = typeof(GenerateCommand).GetMethod(
+            "GetOutputPath",
+            BindingFlags.NonPublic | BindingFlags.Static,
+            null,
+            [typeof(Settings), typeof(RefitGeneratorSettings)],
+            null);
+
+        method.Should().NotBeNull();
+
+        return (string)method!.Invoke(null, [settings, refitGeneratorSettings])!;
+    }
+
+    private static void ApplySettingsFileDefaults(string settingsFilePath, RefitGeneratorSettings refitGeneratorSettings)
+    {
+        var method = typeof(GenerateCommand).GetMethod(
+            "ApplySettingsFileDefaults",
+            BindingFlags.NonPublic | BindingFlags.Static);
+
+        method.Should().NotBeNull();
+        method!.Invoke(null, [settingsFilePath, refitGeneratorSettings]);
+    }
+
+    private static string CreateTempDirectory()
+    {
+        var tempDir = Path.Combine(Path.GetTempPath(), $"refitter-test-{Guid.NewGuid()}");
+        Directory.CreateDirectory(tempDir);
+        return tempDir;
+    }
+
+    private static void CleanupDirectory(string path)
+    {
+        if (Directory.Exists(path))
+            Directory.Delete(path, recursive: true);
+    }
+}

src/Refitter.Tests/Examples/TrimUnusedSchemaAliasWithLeadingDigitPropertyTests.cs

@@ -233,4 +233,4 @@ private static async Task<string> GenerateCodeFromSpec(string openApiSpec)
             }
         }
     }
-}
+}