All reference objects should be detached when written to a property of
a QML-defined type. This is in line with what happens if you write the
same object to a property of a C++-defined type and doing anything else
makes very little sense.
In particular, before this change, the behavior differed between
ahead-of-time compiled code and interpreted code, between writing to
"var" properties and writing to typed properties, and between different
kinds of lists. Now everything we recognize as reference object always
gets detached when writing to a property.
[ChangeLog][QtQml][Important Behavior Changes] Writing a list or value
type to a QML-declared property now always detaches this same list or
value from any locals or other properties you may have read it from.
Therefore, subsequent changes to its "source" will not affect it
anymore. This is in line with what we do to C++-declared properties.
Fixes: QTBUG-127957
Change-Id: Icdf188ef29d28e5d3aaa8219cc003e07e8813f38
Reviewed-by: Olivier De Cannière <olivier.decanniere@qt.io>
Ulf Hermann