MFTEnumEx signature incorrect

[jimm98y]

Actual behavior

The signature of the generated MFTEnumEx is not correct, causing a crash. This used to be working in 0.3.49-beta, it is broken since the latest version 0.3.106. The new generated function in the latest version is:

public static unsafe winmdroot.Foundation.HRESULT MFTEnumEx(global::System.Guid guidCategory, winmdroot.Media.MediaFoundation.MFT_ENUM_FLAG Flags, winmdroot.Media.MediaFoundation.MFT_REGISTER_TYPE_INFO? pInputType, winmdroot.Media.MediaFoundation.MFT_REGISTER_TYPE_INFO? pOutputType, out winmdroot.Media.MediaFoundation.IMFActivate pppMFTActivate, out uint pnumMFTActivate)

In 0.3.49-beta which was working it is:

public static unsafe winmdroot.Foundation.HRESULT MFTEnumEx(global::System.Guid guidCategory, winmdroot.Media.MediaFoundation.MFT_ENUM_FLAG Flags, winmdroot.Media.MediaFoundation.MFT_REGISTER_TYPE_INFO? pInputType, winmdroot.Media.MediaFoundation.MFT_REGISTER_TYPE_INFO? pOutputType, out winmdroot.Media.MediaFoundation.IMFActivate[] pppMFTActivate, out uint pnumMFTActivate)

You can notice the IMFActivate[] parameter is now typed as IMFActivate which is why it's not working. The definition looks correct:

STDAPI
MFTEnumEx(
    _In_                                GUID                            guidCategory,
    _In_                                UINT32                          Flags,
    _In_opt_                            const MFT_REGISTER_TYPE_INFO*   pInputType,
    _In_opt_                            const MFT_REGISTER_TYPE_INFO*   pOutputType,
    _Outptr_result_buffer_(*pnumMFTActivate) IMFActivate***                 pppMFTActivate,
    _Out_                               UINT32*                         pnumMFTActivate
);

Expected behavior

The function definition should include IMFActivate[] and calling it should not crash the app.

Repro steps

1. NativeMethods.txt content:

mf.*
mfplat.*
MF*
_MFT_INPUT_STATUS_FLAGS
_MFT_PROCESS_OUTPUT_FLAGS
_MFT_PROCESS_OUTPUT_STATUS
_MFT_OUTPUT_DATA_BUFFER_FLAGS
MFT_INPUT_STREAM_INFO
MFT_OUTPUT_STREAM_INFO
MFT_MESSAGE_TYPE
MFT_OUTPUT_DATA_BUFFER

2. NativeMethods.json content (if present):

{
  "$schema": "https://aka.ms/CsWin32.schema.json",
  "public": true,
  "wideCharOnly": false,
  "allowMarshaling": true,
  "comInterop": {
    "preserveSigMethods": [ "IMFTransform" ]
  }
}

3. Any of your own code that should be shared?

PInvoke.MFTEnumEx(category, flags, input, output, out IMFActivate[] activates, out uint activateCount)

Context

• CsWin32 version: 0.3.106
• Win32Metadata version (if explicitly set by project):
• Target Framework: net8.0