Qml set context property for child item

Anonimista

I want to set a context property of a Qml Button from PySide6 but I get an error. Here are the relevant files:

import sys

from PySide6.QtCore import QObject, Slot
from PySide6.QtGui import QGuiApplication
from PySide6.QtQml import (QQmlApplicationEngine, QmlElement,
    QQmlComponent, QQmlContext)


QML_IMPORT_NAME = "EventHandlers"
QML_IMPORT_MAJOR_VERSION = 1


@QmlElement
class EventHandler(QObject):
    
    def __init__(self, parent=None):
        super().__init__(parent)
        
    @Slot()
    def on_button_click(self):
        print('Button clicked')


if __name__ == '__main__':

    app = QGuiApplication(sys.argv)
    
    engine = QQmlApplicationEngine()
    engine.quit.connect(app.quit)
    engine.load('view.qml')
    
    event_handler = EventHandler()
        
    root = engine.rootObjects()[0]
    button3 = root.findChild(QObject, 'button3')
    button3.clicked.connect(event_handler.on_button_click)
    
    engine.rootContext().setContextProperty('python_handler', event_handler)
    
    button5 = root.findChild(QObject, 'button5')

    button5_context = QQmlContext(engine, button5)
    button5_context.setContextProperty('evt_handler', event_handler)
    
    result = app.exec()
    del engine
    
    sys.exit(result)

view.qml:

import QtQuick
import QtQuick.Controls
import QtQuick.Layouts
import EventHandlers


ApplicationWindow {

    visible: true
    width: 200
    height:400
    title: "HelloApp"
    
    EventHandler {
        id: eventHandler
    }

    ColumnLayout {
        
        id: layout
        objectName: "layout"
        anchors.fill: parent
    
        Button {
            id: button1
            Layout.fillWidth: true
            Layout.fillHeight: true
            text: "Qml event handler"
            onClicked: console.log("Button clicked")
        }
        
        Button {
            id: button2
            Layout.fillWidth: true
            Layout.fillHeight: true
            text: "PySide -> Qml event handler"
            onClicked: eventHandler.on_button_click()
        }

        Button {
            id: button3
            objectName: "button3"
            Layout.fillWidth: true
            Layout.fillHeight: true
            text: "Qml -> PySide event handler"
        }
        
        Button {
            id: button4
            objectName: "button4"
            Layout.fillWidth: true
            Layout.fillHeight: true
            text: "Root context event"
            onClicked: python_handler.on_button_click()
        }
        
        Button {
            id: button5
            objectName: "button5"
            Layout.fillWidth: true
            Layout.fillHeight: true
            text: "Child context event"
            onClicked: evt_handler.on_button_click()
        }
    }

}

The error I get:

view.qml:63: ReferenceError: evt_handler is not defined

Why this no work? The root context property work fine but button5 (last button) cannot set context property