Split Variant marshalling tests

src/coreclr/vm/interopconverter.cpp

@@ -188,18 +188,29 @@ IUnknown *GetComIPFromObjectRef(OBJECTREF *poref, ComIpType ReqIpType, ComIpType
         if (ReqIpType & ComIpType_Dispatch)
         {
             hr = SafeQueryInterface(pUnk, IID_IDispatch, &pvObj);
-            pUnk->Release();
+            if (SUCCEEDED(hr))
+            {
+                pUnk->Release();
+                FetchedIpType = ComIpType_Dispatch;
+            }
+            else if (ReqIpType & ComIpType_Unknown)
+            {
+                hr = S_OK;
+                pvObj = pUnk;
+                FetchedIpType = ComIpType_Unknown;
+            }
         }
         else
         {
             pvObj = pUnk;
+            FetchedIpType = ComIpType_Unknown;
         }
 
         if (FAILED(hr))
             COMPlusThrowHR(hr);
 
         if (pFetchedIpType != NULL)
-            *pFetchedIpType = ReqIpType;
+            *pFetchedIpType = FetchedIpType;
 
         RETURN pvObj;
     }

src/tests/Interop/PInvoke/Variant/VariantTest.BuiltInCom.cs

@@ -0,0 +1,37 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Runtime.InteropServices;
+using TestLibrary;
+using static VariantNative;
+
+#pragma warning disable CS0612, CS0618
+partial class Test
+{
+    public static int Main()
+    {
+        bool builtInComDisabled=false;
+        var comConfig = AppContext.GetData("System.Runtime.InteropServices.BuiltInComInterop.IsSupported");
+        if(comConfig != null && !bool.Parse(comConfig.ToString()))
+        {
+            builtInComDisabled=true;
+        }
+
+        Console.WriteLine($"Built-in COM Disabled?: {builtInComDisabled}");
+        try
+        {
+            TestByValue(!builtInComDisabled);
+            TestByRef(!builtInComDisabled);
+            TestOut();
+            TestFieldByValue(!builtInComDisabled);
+            TestFieldByRef(!builtInComDisabled);
+        }
+        catch (Exception e)
+        {
+            Console.WriteLine($"Test failed: {e}");
+            return 101;
+        }
+        return 100;
+    }
+}

src/tests/Interop/PInvoke/Variant/VariantTest.ComWrappers.cs

@@ -0,0 +1,114 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using TestLibrary;
+using static VariantNative;
+using ComTypes = System.Runtime.InteropServices.ComTypes;
+
+#pragma warning disable CS0612, CS0618
+partial class Test
+{
+    public static int Main()
+    {
+        bool testComMarshal=true;
+        ComWrappers.RegisterForMarshalling(new ComWrappersImpl());
+        try
+        {
+            TestByValue(testComMarshal);
+            TestByRef(testComMarshal);
+            TestOut();
+            TestFieldByValue(testComMarshal);
+            TestFieldByRef(testComMarshal);
+        }
+        catch (Exception e)
+        {
+            Console.WriteLine($"Test failed: {e}");
+            return 101;
+        }
+        return 100;
+    }
+}
+
+internal unsafe class ComWrappersImpl : ComWrappers
+{
+    private static readonly ComInterfaceEntry* wrapperEntry;
+
+    static ComWrappersImpl()
+    {
+        var vtblRaw = (IntPtr*)RuntimeHelpers.AllocateTypeAssociatedMemory(typeof(IDispatchVtbl), sizeof(IntPtr) * 7);
+        GetIUnknownImpl(out vtblRaw[0], out vtblRaw[1], out vtblRaw[2]);
+
+        vtblRaw[3] = (IntPtr)(delegate* unmanaged<IntPtr, IntPtr, int>)&IDispatchVtbl.GetTypeInfoCountInternal;
+        vtblRaw[4] = (IntPtr)(delegate* unmanaged<IntPtr, int, int, IntPtr, int>)&IDispatchVtbl.GetTypeInfoInternal;
+        vtblRaw[5] = (IntPtr)(delegate* unmanaged<IntPtr, IntPtr, IntPtr, int, int, IntPtr, int>)&IDispatchVtbl.GetIDsOfNamesInternal;
+        vtblRaw[6] = (IntPtr)(delegate* unmanaged<IntPtr, int, IntPtr, int, ComTypes.INVOKEKIND, IntPtr, IntPtr, IntPtr, IntPtr, int>)&IDispatchVtbl.InvokeInternal;
+
+        wrapperEntry = (ComInterfaceEntry*)RuntimeHelpers.AllocateTypeAssociatedMemory(typeof(IDispatchVtbl), sizeof(ComInterfaceEntry));
+        wrapperEntry->IID = IDispatchVtbl.IID_IDispatch;
+        wrapperEntry->Vtable = (IntPtr)vtblRaw;
+    }
+
+    protected override unsafe ComInterfaceEntry* ComputeVtables(object obj, CreateComInterfaceFlags flags, out int count)
+    {
+        // Always return the same table mappings.
+        count = 1;
+        return wrapperEntry;
+    }
+
+    protected override object CreateObject(IntPtr externalComObject, CreateObjectFlags flags)
+    {
+        throw new NotImplementedException();
+    }
+
+    protected override void ReleaseObjects(IEnumerable objects)
+    {
+        throw new NotImplementedException();
+    }
+}
+public struct IDispatchVtbl
+{
+    internal static readonly Guid IID_IDispatch = new Guid("00020400-0000-0000-C000-000000000046");
+
+    [UnmanagedCallersOnly]
+    public static int GetTypeInfoCountInternal(IntPtr thisPtr, IntPtr i)
+    {
+        return 0; // S_OK;
+    }
+
+    [UnmanagedCallersOnly]
+    public static int GetTypeInfoInternal(IntPtr thisPtr, int itinfo, int lcid, IntPtr i)
+    {
+        return 0; // S_OK;
+    }
+
+    [UnmanagedCallersOnly]
+    public static int GetIDsOfNamesInternal(
+        IntPtr thisPtr,
+        IntPtr iid,
+        IntPtr names,
+        int namesCount,
+        int lcid,
+        IntPtr dispIds)
+    {
+        return 0; // S_OK;
+    }
+
+    [UnmanagedCallersOnly]
+    public static int InvokeInternal(
+        IntPtr thisPtr,
+        int dispIdMember,
+        IntPtr riid,
+        int lcid,
+        ComTypes.INVOKEKIND wFlags,
+        IntPtr pDispParams,
+        IntPtr VarResult,
+        IntPtr pExcepInfo,
+        IntPtr puArgErr)
+    {
+        return 0; // S_OK;
+    }
+}