577d698b8e changed QString::isUpper /
isLower behaviors to match Unicode semantics: a string is uppercase
if it's identical to its own toLower/toUpper folding. These semantics
come from Unicode so they're not up for debate.
That commit however left QByteArray untouched. Generally speaking, we
want to move away from QByteArray as "text storage" -- this has
partially happened between Qt 5 and Qt 6, where QByteArray went from
Latin-1 semantics to ASCII semantics. Still, QByteArray offers
toUpper/toLower and isUpper/isLower and all this family of functions
should be consistent in behavior.
Apply the same fix that was applied to QString.
[ChangeLog][Important Behavior Changes] The semantics of
QByteArray::isLower() and QByteArray::isUpper() have been changed. Now
lowercase (resp. uppercase) byte arrays are allowed to contain any
character; a byte array is considered lowercase (resp. uppercase) if
it's equal to its own toLower() (resp. toUpper()) folding. For instance,
the "abc123" byte array is now considered to be lowercase.
Previously, the isLower() (resp. isUpper()) functions checked whether
the byte array only contained ASCII lowercase (resp. uppercase)
characters, and was at least 1 character long. This had the side effect
that byte array containing ASCII non-letters (e.g. numbers, symbols,
etc.) were not lowercase nor uppercase.
[ChangeLog][QtCore][QByteArray] QByteArray::isLower() and
QByteArray::isUpper() now work correctly with empty byte arrays. The
semantics of these functions have been changed.
Pick-to: 6.3 6.2
Fixes: QTBUG-100107
Change-Id: Id56a42f01b2d1af5387bf0e6ccff0f824f757155
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>