Readonly property

This warning category is spelled [read-only-property] by qmllint.

Cannot assign to read-only property

What happened?

A read-only property was written.

Why is this bad?

The QML engine will throw a Type Error when it sees the write to a read-only property.

Example

 import QtQuick

 Item {
     id: root
     readonly property int someNumber: 10

     Component.onCompleted: {
         someNumber = 20  // not ok: TypeError: Cannot assign to read-only property
     }
 }

To fix this warning, remove the write to the read-only property, write to another non-read-only property, or remove the readonly modifier if you are the author of the property definition.