[REG 6.6 → 6.7] bogus "TypeError: Cannot read property 'Foo' of undefined" error when using enums

Testing Qt 6.7 gives unexpected errors in some KDE code. https://invent.kde.org/nicolasfella/qml-enum-test is a condensed example.

The error occurs in the Separator component when accessing the enum values defined in this file:

file:///home/nico/kde/usr/qml/org/kde/mymodule/Separator.qml:15: TypeError: Cannot read property 'Light' of undefined

file:///home/nico/kde/usr/qml/org/kde/mymodule/Separator.qml:13: TypeError: Cannot read property 'Normal' of undefined 

The example should show a horizonal line, but it doesn't work. Running the example a second time works as expected. After clearing the qml cache (rm -r ~/.cache/foo) it is broken again.

The qml module provides the Separator component and registers the QML file via qmlRegisterType(QUrl, ...). Without this everything works as expected.

To make the example work it must be installed. To install the QML module I copied some code from extra-cmake-modules to work around QTBUG-100102

Tested with current 6.7 branch (qtbase 98af9bd9d363ff5f8525bebe0e6be431679881ff, qtdeclarative 44126abbdbd49b7764e23deb2c03f40f98e660c5). It works as expected with 6.6