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  1. Qt
  2. QTBUG-50992

QQC2: Object destroyed during incubation

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    Description

      Using customized controls in item views or asynchronous loader often leads to "Object destroyed during incubation" or "Error creating delegate". The problem occurs with basically any control when replacing the default background, content item, or any other building block with a custom one. Controls cleanup the old default content, which leads to a "Object destroyed during incubation" -error, and then the incubation of the whole control fails.

      In item views the problem occurs occasionally, leading to missing delegate instances (QML VisualDataModel: Error creating delegate):

      import QtQuick 2.6
import QtQuick.Controls 2.0

ApplicationWindow {
    visible: true
    width: 640
    height: 480

    GridView {
        id: gridThing;
        anchors.fill: parent;
        cellWidth: 75;
        cellHeight: 75;
        model: 500;

        delegate: Button {
            id: control
            text: "Test"
            width: gridThing.cellWidth;
            height: gridThing.cellHeight;
            background: Rectangle {
                implicitHeight: 20;
                implicitWidth: 20;
                color: "red";
                width: control.width;
                height: control.height;
                x: 0;
                y: 0;
            }
        }
    }
}

      In asynchronous loaders the issue is 100% reproducible with certain control structures:

      import QtQuick 2.6
import QtQuick.Controls 2.0

ApplicationWindow {
    id: root
    visible : true
    width   : 640
    height  : 480

    property bool  triggerTheBug: true // Swap this to see a normal display of the ComboBox

    StackView {
        id: myStackView
        anchors.fill: parent
        initialItem: Loader {
            anchors.fill: parent
            asynchronous    : triggerTheBug
            sourceComponent :
                ComboBox { popup      : Popup{} }         // BUG
            //ComboBox { background : Rectangle{} }     // BUG
            //ComboBox { contentItem: Rectangle{} }     // BUG
            //ComboBox { delegate   : ItemDelegate{} }  // NO BUG
        }
    }
}

      Under the hood, the problem is that QQmlIncubator + QQmlObjectCreator + QQmlVMEGuard tracks all instantiated child objects using QPointer and doesn't like that any of them gets destroyed during the incubation process. Calling deleteLater() is not sufficient, because it would not be synchronized with the incubation controller.

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          depends on

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-63200 Deferred properties are not always executed

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed
          is duplicated by

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-53400 Adding asynchronous Loader into StackView results in "Object destroyed during incubation" error

          • Not Evaluated - Not yet evaluated/prioritized
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-52096 Qt Quick Controls 2 Button fails creation in GridView

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-52955 Regression: ItemDelegate with overriden contentItem in ListView fails to create on Android

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-53496 Customized Qt.labs ComboBox won't display in an asynchronous Loader

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed
          is required for

          Bug - A problem which impairs or prevents the functions of the product. AUTOSUITE-189 Regression on Qt 5.9.4 breaks Neptune Styling

          • P0: Blocker - MUST be fixed ASAP. This includes issues that prevent/block further Qt development; Legal issues & Serious data loss issues.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-85097 Async loader and QQC2: Object destroyed during incubation

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed
          relates to

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-98439 "Binding on contentItem is not deferred as requested by the DeferredPropertyNames class info because it constitutes a group property" when instantiating ScrollBar

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed
          resulted in

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-65955 Button is not visible if its background property is set as a Rectangle

          • Not Evaluated - Not yet evaluated/prioritized
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-65880 [REG 5.9.3 => 5.9.4] Popup opened at 0, 0 has no background

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-65962 [REG: 5.9.3->5.9.4] ComboBox popup doesn't show up

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-66449 QML RangeSlider Crash

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-66453 REG: Material elevation in Page header

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-66614 REG: ToolButton.contentItem for anchors and source for ColorOverlay no longer works

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-67334 Regression: ScrollView+TextArea do not scroll correctly

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-57823 TabBar does not display when setting contentItem property

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-63036 qmlDeferredExecute() crashes with grouped properties

          • 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
              taipan BogDan Vatra
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                Updated:
                Resolved:

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