The stored layout direction used to get changed during initialization
to what was auto-detected based on the translation. Changing the
translation then overwrote that stored value, even if an explicit call
to setLayoutDirection was made by the application.
Calling QGuiApplication::setLayoutDirection(Auto) has so far been a
no-op.
Change this logic so that the stored layout direction continues to be
LayoutDirectionAuto also if it's set based on auto-detection, and only
overwrite it when explicitly called with a non-Auto value. This way,
applications can set a layout direction that stays unchanged even when
translators are installed.
Add test coverage that uses a QTranslator.
In practice, this is not a change of behavior, unless applications called
setLayoutDirection(Auto) (which is no longer a no-op), or called
setLayoutDirection() and then installed a translator and expected the
translator's layout direction to come into effect in spite of the explicit
setting.
[ChangeLog][Gui][QGuiApplication] Calling setLayoutDirection with a non-
auto value now disables the auto-detection based on installed
translators. Applications that explicitly set a layout direction and also
want translators installed afterwards to take effect should reset the
layout direction to Auto, which is now no longer a no-op.
Fixes: QTBUG-100632
Pick-to: 6.3
Change-Id: I1fdcebd43a9b1b468ff95bf15f53f441bb214e08
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
4cca8ee527