[Bug 56598] New: Calling [vararg] method via ITypeLib without arguments via IDispatch fails

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=56598

Bug ID: 56598
           Summary: Calling [vararg] method via ITypeLib without arguments
                    via IDispatch fails
           Product: Wine
           Version: 9.6
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: blocker
          Priority: P2
         Component: oleaut32
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Our COM-interface expose a method that take 0-N opptional parameters via
[vararg].

[vararg]
HRESULT Test([in] VARIANT mandatory, [in] SAFEARRAY(VARIANT) optional, [out,
retval] VARIANT* result);

Calling this method result in error when no arguments are specified, which
breaks compatibility with native Windows.

Calling with arguments works.

Problem may relate to SafeArrayCreate not supporting empty arrays in Wine. Or
to missing handling for edge-case in typelib.c (arround line 7363).

To progress testing we added workaround for our API, but this will affect
compatibility in other areas.