Darwin turns out to know about offset changes a million years into the future, but to not admit to there being any transitions more than (a bit over) half a million years into the future. It thus failed the non-ShortData part of tst_QDateTime::timeZones(), thanks to using correct offsets that showed there must be a transition in the interval, but not believing in that transition. The discrepancy leads to QTimeZonePrivate::stateAtZoneTime() getting valid data for before and after the transition, with different offsets, so amend its "no later transitions" early return to check the offsets do in fact match. If they don't fall back on the code that handles the case where we don't know about transitions but do have offset data. Pick-to: 6.8 6.7 Fixes: QTBUG-126391 Change-Id: Iefda439377ebc3025f2b754e2ec686fcc6361a1b Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io> Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>