Re: [PATCH 0/6] MR5931: winegstreamer: Implement output type functions.

[Rémi Bernon (＠rbernon)]

Rémi Bernon (@rbernon) commented about dlls/mf/tests/transform.c:
>      winetest_push_context("%s", debugstr_a(attr->name));
> -
>    hr = IMFMediaType_DeleteItem(media_type, attr->key);
>    ok_(__FILE__, line)(hr == S_OK, "DeleteItem returned %#lx\n", hr);
> -
>    hr = IMFTransform_SetInputType(transform, 0, media_type, MFT_SET_TYPE_TEST_ONLY);
>    todo_wine_if(attr->todo)
>    ok_(__FILE__, line)(FAILED(hr) == attr->required, "SetInputType returned %#lx.\n", hr);
> -
> -
>    if (attr->required_set)
> -
>    {
> -
>        hr = IMFTransform_SetInputType(transform, 0, media_type, 0);
> -
>        ok_(__FILE__, line)(FAILED(hr), "SetInputType Succeeded.\n");
> -
>        hr = IMFTransform_SetInputType(transform, 0, NULL, 0);
> -
>        ok_(__FILE__, line)(hr == S_OK, "Failed to clear input type.\n");
> -
>    }

So, I understand this is to check that after a media type has been set with some specific attribute you cannot unset the media type? But can you still change it? Change the value of the attribute?

I'm a bit unsure that doing this check here is safe. I think it might have side effects on other attribute, and makes the later iteration results less reliable.

Maybe a separate helper to check that would be better?