Add test for cross-winmd IInspectable derivation and fix a tiny bug (#1547)

Author: jevansaks

src/Microsoft.Windows.CsWin32/Generator.Com.cs

@@ -134,7 +134,7 @@ private static StatementSyntax ThrowOnHRFailure(ExpressionSyntax hrExpression) =
                     foreach (QualifiedTypeDefinitionHandle baseType in baseTypes)
                     {
                         TypeDefinition baseTypeDef = baseType.Generator.Reader.GetTypeDefinition(baseType.DefinitionHandle);
-                        if (this.FindGuidAttribute(baseTypeDef.GetCustomAttributes()) is null)
+                        if (baseType.Generator.FindGuidAttribute(baseTypeDef.GetCustomAttributes()) is null)
                         {
                             canDeclareAsInterface = false;
                             break;

test/CsWin32Generator.Tests/CsWin32GeneratorTests.cs

@@ -542,4 +542,21 @@ public async Task VerifyOverloadPriorityAttributeInNet8(LanguageVersion langVers
             Assert.Empty(methodsWithAttribute);
         }
     }
+
+    [Theory, CombinatorialData]
+    public async Task CrossWinMD_IInspectable(
+        [CombinatorialValues([false, true])] bool allowMarshaling,
+        [CombinatorialValues([null, "TestPInvoke"])] string pinvokeClassName,
+        [CombinatorialValues(["net8.0", "net9.0"])] string tfm)
+    {
+        this.compilation = this.starterCompilations[tfm];
+        this.win32winmdPaths = [.. this.win32winmdPaths!, CustomIInspectableMetadataPath];
+        this.nativeMethodsJsonOptions = new NativeMethodsJsonOptions
+        {
+            AllowMarshaling = allowMarshaling,
+            ClassName = pinvokeClassName,
+        };
+        this.nativeMethods.Add("ITestDerivedFromInspectable");
+        await this.InvokeGeneratorAndCompile($"{nameof(this.CrossWinMD_IInspectable)}_{tfm}_{allowMarshaling}_{pinvokeClassName ?? "null"}");
+    }
 }

test/CsWin32Generator.Tests/CsWin32GeneratorTestsBase.cs

@@ -21,6 +21,12 @@ public enum TestOptions
     DoNotFailOnDiagnostics = 2,
 }
 
+public record NativeMethodsJsonOptions(
+    bool? AllowMarshaling = null,
+    bool? EmitSingleFile = null,
+    bool? Public = null,
+    string? ClassName = null);
+
 public partial class CsWin32GeneratorTestsBase : GeneratorTestBase
 {
     protected bool fullGeneration;
@@ -35,6 +41,7 @@ public partial class CsWin32GeneratorTestsBase : GeneratorTestBase
     protected int expectedExitCode = 0;
     protected string? tfm;
     protected string[]? win32winmdPaths;
+    protected NativeMethodsJsonOptions? nativeMethodsJsonOptions;
 
     public CsWin32GeneratorTestsBase(ITestOutputHelper logger)
         : base(logger)
@@ -99,6 +106,16 @@ protected async Task InvokeGenerator(string outputPath, string testCase, TestOpt
             File.WriteAllLines(nativeMethodsTxtPath, this.nativeMethods);
         }
 
+        if (this.nativeMethodsJsonOptions is NativeMethodsJsonOptions generatorOptions)
+        {
+            string nativeMethodsJsonPath = Path.Combine(this.GetTestCaseOutputDirectory(testCase), "NativeMethods.json");
+            var jsonOptions = new System.Text.Json.JsonSerializerOptions { WriteIndented = true };
+            jsonOptions.DefaultIgnoreCondition = System.Text.Json.Serialization.JsonIgnoreCondition.WhenWritingDefault;
+            string jsonContent = System.Text.Json.JsonSerializer.Serialize(generatorOptions, jsonOptions);
+            File.WriteAllText(nativeMethodsJsonPath, jsonContent);
+            this.nativeMethodsJson = Path.GetFileName(nativeMethodsJsonPath);
+        }
+
         Directory.CreateDirectory(outputPath);
 
         this.Logger.WriteLine($"OutputPath: {outputPath}");