inheritance-cycle.qdoc

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// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
 
/*!
\page qmllint-warnings-and-errors-inheritance-cycle.html
\ingroup qmllint-warnings-and-errors
 
\title Inheritance cycle
\brief [inheritance-cycle] A component inherits from itself.
 
\qmllintwarningcategory inheritance-cycle
 
\section1 Component is part of an inheritance cycle
 
\section2 What happened?
A component inherited directly or indirectly from itself.
 
Usually, Components can inherit properties, methods, signals and enums from other components.
 
If a component inherits itself directly or indirectly through another base component, then
it forms an inheritance cycle. The warning indicates that the current component is inside an
inheritance cycle, see \l{#example}{Example}.
 
\section2 Why is this bad?
Components with inheritance cycles will not be created at runtime: they will be null instead.
 
\section2 Example
\qml
import QtQuick
 
Item {
    component Cycle: Cycle {} // not ok: directly inherits from itself
    component C: C2 {}        // not ok: indirectly inherits from itself
    component C2: C{}
}
\endqml
To fix this warning, break up the inheritance cycle:
\qml
import QtQuick
 
Item {
    component Cycle: Item {}  // ok: does not inherit from itself
    component C: C2 {}        // ok: does not indirectly inherits from itself anymore
    component C2: Cycle{}
}
\endqml
*/