[qt/qt/qtbase]: Summary of bulk changes made

Git repository change summary for qt/qt/qtbase
Pushed by mirror-service into branch '6.11'.
Changed from 71c9a71a9dad81b84bb135bbd3bc91cda31f2dfd to 96f5a8c9d1d55f187af9edfc2db3e7757610b740
Acknowledgement was received that this change introduces only existing code that has been pushed to another public open source repository.

This change contains the following new commits:

Git commit dbb7839213b762679c51ffaaf5e2976cc7dd7949 by Edward Welbourne on 13/08/2026 at 17:37..
Fix overflow in QIslamicCivilCalendar::isLeapYear()

Credit to OSS-Fuzz for spotting the overflow on huge year.
As for the similar Jalali case, reduce the year in advance to its
remainder in the modulus applied to the arithmetic it's used in.  We
can then safely scale and add an offset without overflow hazards.

Add a new test for QCalendar that probes isLeapYear() near the
extremes of int's range. Structure this ready for some additions to
probe the range of dates supported by QDate.

Add tests of QtParseTemporal and QDateTime (to be dropped on picking
past 6.12) that exercise the date that triggered overflow.

On picking to 6.11, drop tst_QtParseTemporal tests (don't exist until
6.12) and the changes to tst_QDateTime (the pre-6.12 parser doesn't
support years with more than four digits).

Pick-to: 6.8
Fixes: QTBUG-148792
Change-Id: Id58e3691e06791170d8ed435b967b256629617ba
Reviewed-by: Thiago Macieira <[email protected]>
(cherry picked from commit 94a6fc5d1972a56943d12d6b96f1fbb62e66a3e6)
Reviewed-by: Qt Cherry-pick Bot <[email protected]>
(cherry picked from commit feed7620d86d0af538064e15cd1ba0f13e81c0a3)
Reviewed-by: Robert Löhning <[email protected]>
https://invent.kde.org/qt/qt/qtbase/-/commit/dbb7839213b762679c51ffaaf5e2976cc7dd7949

Git commit d1a6e172b3ac6622ca20d3ea3452d28aec973c34 by Edward Welbourne on 13/08/2026 at 17:37..
Amend daysInMonth() docs of QCalendarBackend to match QCalendar

Amends commit cd442e439b73b8de4e0fc1434320a3ed1a465d2f (6.10), which
amended the contract to report the greatest number of days in the
month when the year is unspecified, instead of the usual (which is
typically smaller when there's a difference). I amended QCalendar's
doc but neglected QCalendarBackend's.

Change-Id: I66682913ebde72acd9dcfb5cb98c1cf5060e34ba
Reviewed-by: Thiago Macieira <[email protected]>
(cherry picked from commit d3cef025c5d058679c92bd47d0e350c7bf530426)
Reviewed-by: Qt Cherry-pick Bot <[email protected]>
(cherry picked from commit 206d162403b2fdfc4e2763d3897d9196afe13344)
https://invent.kde.org/qt/qt/qtbase/-/commit/d1a6e172b3ac6622ca20d3ea3452d28aec973c34

Git commit 96f5a8c9d1d55f187af9edfc2db3e7757610b740 by Edward Welbourne on 13/08/2026 at 17:38..
Fix overflows when calendars convert to and from Julian Day number

Prompted by other recent overflow issues, added tests for correct
handling of dates at the ends of the range supported by QDate and each
calendar. Fixed those that failed. Revise QCalendar docs to reflect
the handling of out-of-range values. As a drive-by, mark some local
helpers of the Jalali calendar static.

The range supported by QDate is exactly the range of years that 32-bit
int can represent, from the start of the first to the end of the last,
in the Gregorian calendar. Since the Julian calendar has more leap
years, its representations of this range fall within the int range,
although some dates it can represent map to invalid QDate values. The
other calendars currently supported all have fewer leap years than
Gregorian, which accumulates enough by the ends of the int range to
overshadow the differences in base year.

Pick-to: 6.8
Task-number: QTBUG-147419
Change-Id: I1ea8cb0301d4b03515fa1268adddc7c7ebe3402c
Reviewed-by: Thiago Macieira <[email protected]>
(cherry picked from commit 026bdc5212257b93803e801c4f14e65b8c8b9829)
Reviewed-by: Qt Cherry-pick Bot <[email protected]>
(cherry picked from commit c876ccf34a72c3a9f4cb305b1139c6afb617196e)
Reviewed-by: Robert Löhning <[email protected]>
https://invent.kde.org/qt/qt/qtbase/-/commit/96f5a8c9d1d55f187af9edfc2db3e7757610b740