Up to 5.15.0, QDateTime::fromString(), when parsing a string that matched the format but represented a date-time in a spring-forward's gap, would return an invalid date-time object that represented a "best shot" date-time, correcting the error in the string as best it could. In 5.15, in order to handle time-spec information correctly, we adapted the date-time parser to have a fromString() variant that parsed a date-time as a whole, rather than as a date and a time; as a result, QDTP::fromString() now returns false and QDT::fromString() returned a default-constructed instance instead of the invalid date-time that QDTP had produced. Amend 76054516047d8efb8529443830bb4d9ddf01010f to restore the prior behavior of returning the invalid date-time object from QDTP instead of a default-constructed invalid date-time. Also document what this implies for the caller's ability to recover from the situation, if a best shot result is better than nothing. [ChangeLog][QtCore][QDateTime] Restored pre-5.15.0 behavior when parsing a date-time from a string (and document what it implies): if the string has the right form but represents a date-time that was skipped by a time-zone transition (e.g. a DST spring-forward), the invalid date-time object returned can, none the less, be used to recover a near-by date-time that may be more useful in some cases. From 5.15.0 to 5.15.2 and in 6.0.0, a default-constructed QDateTime was returned in place of this more informative invalid date-time. Task-number: QTBUG-88633 Pick-to: 6.0 5.15 Change-Id: If0b439038d5fe48eefb951c62f3aae2933bb5651 Reviewed-by: Andrei Golubev <andrei.golubev@qt.io> Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>