adding in QtDesigner a custom property "buttonGroupId" does not in fact add this property to final widget

If you add a property "buttonGroupId" to any widget in QtDesigner then:

• it will be added to xxx.ui file
• but it will not be created in resulting ui_xxx.h file generated by uic.

There are also other special property names which may lead to problems.

In the attached example 1, I assign to a button two properties: "testProperty" and "buttonGroupId". This leads to correct test.ui file:

<property name="buttonGroupId" stdset="0">
 <number>1</number>
</property>
<property name="testProperty" stdset="0">
 <string>value</string>
</property>

but in ui_test.h generated by uic during compilation there is only:

pushButton->setProperty("testProperty", QVariant(QApplication::translate("Dialog", "value", 0, QApplication::UnicodeUTF8)));

but no trace of "buttonGroupId".

FYI: it's very confusing: we used to have running code where in constructor of a dialog we did something based on a custom property "btnGrpId" assigned in designer. Then we cleaned-up the code, among other changes we expanded our weird abbreviation to more readable "buttonGroupId". And suddenly our application stopped working! It took us a while to figure out that the problem was that the property assigned in QtDesigner was not in fact assigned (and not visible from c++ code). Just because of change of the name of our property....

It seems that the problem is in qt-git/src/tools/uic/cpp/cppwriteinitialization.cpp:

    DomWidget *buttonGroupWidget = findWidget(QLatin1String("Q3ButtonGroup"));

} else if (propertyName == QLatin1String("buttonGroupId")) { // Q3ButtonGroup support
    if (buttonGroupWidget)
        m_output << m_indent << m_driver->findOrInsertWidget(buttonGroupWidget) << "->insert("
                 << varName << ", " << p->elementNumber() << ");\n";
    continue;
} else if (propertyName == QLatin1String("currentRow") // QListWidget::currentRow

=> if custom property name is "buttonGroupId" and Q3ButtonGroup is not found, then nothing is written.

(Note: that my example does not use any Qt3 support widgets! Above code is a quote from uic code!)

1. I think, if Q3ButtonGroup is not found, we should proceed (and not skip the rest of the for loop by "continue;") i.e. treat buttonGroupId just as any other regular custom property. Thus I would suggest changing the above code to:

} else if (propertyName == QLatin1String("buttonGroupId")) { // Q3ButtonGroup support
    if (buttonGroupWidget) {
        m_output << m_indent << m_driver->findOrInsertWidget(buttonGroupWidget) << "->insert("
                 << varName << ", " << p->elementNumber() << ");\n";
        continue;
    }
} else if (propertyName == QLatin1String("currentRow") // QListWidget::currentRow

(i.e. "continue" only if buttonGroupWidget was found) => I did check that this leads to proper

pushButton->setProperty("buttonGroupId", QVariant(1));

in ui_test.h resulting from uic. Alternatively, condition on button group could be moved to the previous line:

} else if (propertyName == QLatin1String("buttonGroupId" && buttonGroupWidget )) { // Q3ButtonGroup support
    m_output << m_indent << m_driver->findOrInsertWidget(buttonGroupWidget) << "->insert("
             << varName << ", " << p->elementNumber() << ");\n";
    continue;
} else if (propertyName == QLatin1String("currentRow") // QListWidget::currentRow

which puts it more in line with other sections in this stream of "else-ifs".

2. But, I think, additionally this whole part of uic code has to be reviewed.

Most cases in this series of ifs in the uic source are quite safe: they are restricted to specific widgets (e.g. tabSpacing only for QToolBox) which is fine. But there are a few which are not limited in this way. For example, when I add to a pushbutton a benign QStringList property "database", I get during compilation errors (see attached example 2):

main.o: In function `~Ui_Dialog':
uic-properties-example2/ui_test.h:28: undefined reference to `QSqlDatabase::~QSqlDatabase()'
test.o: In function `Ui_Dialog':
uic-properties-example2/ui_test.h:28: undefined reference to `QSqlDatabase::QSqlDatabase()'
test.o: In function `Ui_Dialog::setupUi(QDialog*)':
uic-properties-example2/ui_test.h:35: undefined reference to `QSqlDatabase::database(QString const&, bool)'
uic-properties-example2/ui_test.h:35: undefined reference to `QSqlDatabase::operator=(QSqlDatabase const&)'
uic-properties-example2/ui_test.h:35: undefined reference to `QSqlDatabase::~QSqlDatabase()'
uic-properties-example2/ui_test.h:35: undefined reference to `QSqlDatabase::~QSqlDatabase()'
collect2: ld returned 1 exit status
make: *** [test] Error 1

(I admit that adding QStringList property "database" for some custom purposes is not that likely, but, you know - one day someone will run into this; after all we ourselves did run by accident into the above problem with buttonGroupId in a real-life project!)