This is a followup to 77a8e90cdd which
didn't handle the case where no columns had been moved.
visualIndices and logicalIndices are empty until initializeIndexMapping()
is called, in which case appending is wrong.
As a result, visualIndex(i) would return -1 for the values over
those added by read(), and an assert would happen at painting time.
The fix is to leave visualIndices and logicalIndices empty if
they are empty already, leaving it to initializeIndexMapping()
to fill them later if necessary (e.g. when moving a column).
Task-number: QTBUG-60837
Change-Id: Ia7e4b9d3122647984acd434dfaa0400df319d065
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Reviewed-by: Thorbjørn Lund Martsum <tmartsum@gmail.com>
f6b36eaafe