[Bug 19495] DialogBox() returns -1 for Invalid Window Handle, Should Be 0

http://bugs.winehq.org/show_bug.cgi?id=19495

--- Comment #26 from Andrew Nguyen   2009-08-06 06:30:51 ---
Created an attachment (id=22858)
 --> (http://bugs.winehq.org/attachment.cgi?id=22858)
user32/tests: Test the behavior of DialogBoxParamA with dialog procedure window
destruction.

There is an actual difference in behavior between Wine and Windows, but it's
not due to the parameters passed into DialogBoxParamA. Rather, the actual issue
is the different handling of dialogs that are destroyed by their dialog
procedure, rather than by DialogBoxParamA. While MSDN states that a dialog
procedure should call EndDialog to destroy a dialog, Robert's dialog procedure
calls DestroyWindow on the dialog window handle instead:

switch (message) {
case WM_INITDIALOG:
    PostMessage( hWnd, WM_CLOSE, 0, 0 );
    return 1;
case WM_CLOSE:
    DestroyWindow(hWnd);
    return 0;
case WM_DESTROY:
    PostQuitMessage(3);
    return 0;
default:
    break;
};

Wine's DialogBoxParamA doesn't handle this in the same manner as Windows. Line
812 of DIALOG_DoDialogBox() does:

if (!IsWindow( hwnd )) return -1;

Possibly the return value should be revised to 0. I've attached a test case
demonstrating the issue.