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  1. Qt
  2. QTBUG-90356

Pushing function as property to StackView doesn't result in that property being set

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      I have a component that allows a property to be overridden with a custom function. The idea is that it sets a function by default for convenience, but allows you to set your own:

      import QtQuick 2.12
import QtQuick.Controls 2.12

ApplicationWindow {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")

    Component {
        id: mainMenuComponent

        Button {
            text: "Load game"
            onClicked: StackView.view.push(loadGamePage, {
                contextualActionHandler: function(saveIndex, saveUrl, saveName) {
                   print("correct handler called")
                }
            })
        }
    }

    Component {
        id: loadGamePage

        Item {
            property alias contextualActionHandler: listView.contextualActionHandler

            Button {
                id: listView
                text: "Load this specific saved game"

                property var contextualActionHandler: function(saveIndex, saveUrl, saveName) {
                    print("default contextual action handler called")
                }

                onClicked: contextualActionHandler(0, "foo.json", "foo")
            }
        }
    }

    StackView {
        objectName: "mainStackView"
        initialItem: mainMenuComponent
        anchors.fill: parent
    }
}

      The issue is that the function I pass in is not set. To reproduce the issue:

      • Click on "Load game".
      • Click on "Load this specific saved game"; "correct handler called" should be printed, but instead the default message is.

      Trying something similar with inline components and no StackView works:

      import QtQuick 2.15
import QtQuick.Controls 2.15

ApplicationWindow {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")

    component LoadGamePage: Item {
        property alias contextualActionHandler: listView.contextualActionHandler

        Button {
            id: listView
            text: "Load this specific saved game"

            property var contextualActionHandler: function(saveIndex, saveUrl, saveName) {
                print("default contextual action handler called")
            }

            onClicked: contextualActionHandler(0, "foo.json", "foo")
        }
    }

    LoadGamePage {
        contextualActionHandler: function(saveIndex, saveUrl, saveName) {
           print("correct handler called")
        }
    }
}

      I had a look around trying to find similar bugs, but the closest I found was QTBUG-56125, which doesn't look related, but surprisingly using a binding does work:

      import QtQuick 2.12
import QtQuick.Controls 2.12

ApplicationWindow {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")

    Component {
        id: mainMenuComponent

        Button {
            text: "Load game"
            onClicked: StackView.view.push(loadGamePage, {
                contextualActionHandler: Qt.binding(function() {
                    return function(saveIndex, saveUrl, saveName){ print("correct handler called") }
                })
            })
        }
    }

    Component {
        id: loadGamePage

        Item {
            property alias contextualActionHandler: listView.contextualActionHandler

            Button {
                id: listView
                text: "Load this specific saved game"

                property var contextualActionHandler: function(saveIndex, saveUrl, saveName) {
                    print("default contextual action handler called")
                }

                onClicked: contextualActionHandler(0, "foo.json", "foo")
            }
        }
    }

    StackView {
        objectName: "mainStackView"
        initialItem: mainMenuComponent
        anchors.fill: parent
    }
}

      I don't think using a binding in this case should be necessary.

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          Bug - A problem which impairs or prevents the functions of the product. QTBUG-90373 Cannot write function to var property through alias

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed
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              qt.team.quick.subscriptions Qt Quick and Widgets Team
              mitch_curtis Mitch Curtis
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                Created:
                Updated:
                Resolved:

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