module "QtQml.StateMachine" is not installed in PyQT application

Question

I wanted to use Qt State Machine QML in my PyQt 6 app, however when I try to run it, I get the following error:

QQmlApplicationEngine failed to load component
.../src/qml/Main.qml:8:1: module "QtQml.StateMachine" is not installed

Code:

• main.py:

import sys

from PyQt6.QtGui import QGuiApplication
from PyQt6.QtQml import QQmlApplicationEngine
from PyQt6.QtCore import QObject, pyqtSlot, pyqtSignal

app = QGuiApplication(sys.argv)

engine = QQmlApplicationEngine()
engine.quit.connect(app.quit)

engine.load('qml/Main.qml')

if not engine.rootObjects():
   sys.exit(-1)    

sys.exit(app.exec())

• qml/Main.qml:

Window {

    ...  // Qt State Machine QML Guide code

    DSM.StateMachine {
        id: stateMachine
        // set the initial state
        initialState: s1
    
        // start the state machine
        running: true
    
        DSM.State {
            id: s1
    
            DSM.SignalTransition {
                targetState: s2
                signal: button.clicked
            }
            onEntered: console.log("s1 entered")
            onExited: console.log("s1 exited")
        }
    
        DSM.State {
            id: s2
    
            onEntered: console.log("s2 entered")
            onExited: console.log("s2 exited")
        }
    }

}

To run the app I use pip to install the following packages from requirements.txt:

PyQt6
pyqt6-plugins
PyQt6-Qt6
PyQt6-sip
pyqt6-tools
python-dotenv
qt6-applications
qt6-tools

I think the issue is with some missing package not defined there.

I installed qt6-scxml package for Arch but I still get the same error and right now I am completely clueless.

Does anyone know what the missing pip package is?

Is it even possible to run it in PyQt6?

Answer 1

Apparently the state machine is supported in PySide6 and it’s unclear how it works in PyQt6