[MU4 Issue][Plugins] A "Qt.quit()" instruction in a plugin closes the entire MS4

[lgvr123]

Calling Qt.quit()in a plugin closes the entire MS4.

Although it is not longer recommended for plugin developers to use Qt.quit() to close their plugins, it can still be found in many plugins.

To be reproduced with this basic plugin:

import QtQuick 2.2
import MuseScore 3.0
import QtQuick.Controls 2.2
import QtQuick.Layouts 1.1 // was 1.3 in MS3, but 1.1 in Temperaments
import QtQuick.Window 2.3

MuseScore {
    menuPath: "Plugins.testBasicGUI"
    description: "This plugins shows a BasicGUI "
    version: "1.0"
    requiresScore: false
    pluginType: "dialog"
    id: mainWindow
    width : 300
    height : 300
    
    ColumnLayout {
        id: container
        anchors.margins: 5
        anchors.fill: parent
        spacing: 5
        CheckBox {
            text: "I'm the default component"
            checked: true
        }

        Button {
            text: qsTranslate("QPlatformTheme", "Close")
            Layout.alignment: Qt.AlignLeft
            onClicked: {
                //mainWindow.parent.Window.window.close();
                Qt.quit(); // as found in many-many plugins --> closes MS4
            }
        }
    }
}

[Jojo-Schmitz]

Related to #8859, which has been moved to 4.x

[Eism]

Should be quit() instead of Qt.quit()

[Jojo-Schmitz]

Well, it is Qt.quit() in many existing plugins, that's the (compatibility) problem here

[JeffRocchio]

fwiw, Qt.quit() explains my issue #13089. I just modified my 3.6 plugins to change Qt.quit() to quit() and now they all work fine.

To Jojo's point - if not addressed, then upon release of MS4 I have to believe there will be a lot of noise concerning this incompatability.