Focus abstraction in 58d5d4b7c2 was
supposed to be behavior-neutral. QWidgetPrivate::reparentFocusChildren
used QObject::findChildren() to find children inside and outside the
current focus chain. If the re-parented widget had only direct children
and the focus chain was equal to creation-order, the result was
identical to previous behavior.
When the re-parented widget had grandchildren, the behavior differred.
While not being detected by existing tests, it caused a regression.
Re-implement the previous logic: Iterate through the focus chain,
instead of relying on QObject::findChildren() returning a complete and
well-ordered list.
Modify tst_QWidget::focusChainOnReparent() in order to cover the
regression.
This amends 58d5d4b7c2.
Fixes: QTBUG-125257
Change-Id: Iff4f1d0d9b6117c50c8980dfb6eebfc6f6d4a710
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
2d4993899f