Synchronized TabBars inside StackLayout

[Eligijus]

Hello,
I want synchronized TabBars inside StackLayout aka there are multiple TabBars inside StackLayout and changing TabBar currentIndex every other TabBar and StackLayout currentIndex should also change to that index .My current code works but I'm worried about recursion. Code where recursion might occur I commented //Important!. Should I be worried or does it look ok?

Window {
    visible: true
    width: 640
    height: 480

    StackLayout {
        id: stack
        width: 200
        height: 200

        Rectangle {
            color: "blue"
            TabBar {
                id: nav
                anchors.bottom: parent.bottom
                width: parent.width
                currentIndex: stack.currentIndex //Important!
                TabButton {
                    text: "1"
                }
                TabButton {
                    text: "2"
                }
                onCurrentIndexChanged: stack.currentIndex = currentIndex //Important!
            }
        }

        Rectangle {
            color: "red"
            TabBar {
                id: navB
                anchors.bottom: parent.bottom
                width: parent.width
                currentIndex: stack.currentIndex //Important!
                TabButton {
                    text: "1"
                }
                TabButton {
                    text: "2"
                }
                onCurrentIndexChanged: stack.currentIndex = currentIndex //Important!
            }
        }
    }
}

[Eeli K]

@Eligijus The Qt documentation recommends that when a property value is changed manually (in a C++ object) the notify signal should be emitted only if the value is actually different than the previous value. If they follow their own advice a QML object doesn't notify the change of value if it hasn't changed. Therefore the potential recursion doesn't actually happen and your code works. But I don't know if this implicit behaviour is documented or if it can be trusted.

This can be seen with this test app:

import QtQuick 2.7
import QtQuick.Controls 2.2

ApplicationWindow {
    visible: true
    width: 640
    height: 480

    Button {
        id:b
        anchors.fill: parent
        property int someValue:0
        onClicked: {
            someValue = someValue+1
        }
        onSomeValueChanged: {
            console.log(someValue)
            var x = someValue
            b.someValue = x
            //b.someValue = someValue+1
        }
    }

}

The value of b.someValue is set with the same value and there's no recursion. But if you uncomment the last line there's infinite recursion.