Adding file filter to QFileDialog::getSaveFileName for user to be able to select i.e. "*.tar.gz" and than selecting format from pop up messes up/just appends .tar.gz to previously selected file name instead replacing extension or just add twice extension.

I.e. in Standard dialogs example add filters for *.tar and *.tar.gz:

void Dialog::setSaveFileName()
{
    const QFileDialog::Options options = QFlag(fileDialogOptionsWidget->value());
    QString selectedFilter;
    QString fileName = QFileDialog::getSaveFileName(this,
                                tr("QFileDialog::getSaveFileName()"),
                                saveFileNameLabel->text(),
                                tr("All Files (*);;Text Files (*.txt);;Tar (*.tar);;Tar gzipped (*.tar.gz)"),
                                &selectedFilter,
                                options);
    if (!fileName.isEmpty())
        saveFileNameLabel->setText(fileName);
}

after showing save dialog, typing name test and switching popup to Tar gzipped (*.tar.gz) name becomes test.tar.gz.tar.gz, than switching to something other i.e. to Tar (*.tar) (there is also bug there it doesn't always change extension on first popup change) name becomes test.tar.gz.tar.gz.tar, and going furher switching popup to *.tar.gzip will change to name to test.tar.gz.tar.gz.tar.gz.tar.gz etc.

Even just selecting *.tar.gzip popup, fixing name to be test.tar.gz and clicking Save alert pops up (see attached pictures), and returned name if I select use both is test.tar.gz.tar.gz or selecting use .tar.gz returned name is test.tar.tar.gz

Only workaround I could think of is setting option QFileDialog::HideNameFilterDetails and filter to be "Tar gzipped (*)" and manually adding extension after dialog is closed