QML and future releases compatibility

[2beers]

hi everyone. I want to ask you about the compatibility problems with future qt quick versions.

now we use the code
@import Qt 4.7@

in qml files. but what happens when qt 4.8 is out? we will need to change the code to
@import Qt 4.8@
?

or qt 4.8 will recognize qt 4.7 code? if not I found a serious problem since everyone will need to change their applications every time a new version appear. this is also important on mobile phones when users will update to the latest qt version, and will found that their current applications are not working

[Guest]

I agree, should it have just been

@
import Qt
@

[anselmolsm]

I think QML will follow the Qt compatibility policy: code written with Qt 4.x will continue working in Qt 4.(x+1), etc.

I see import Qt 4.8 as import Qt 4.7 + new QML stuff added in 4.8.

But let's see what Trolls have to say about it :-)

[alexander]

As I understand it means that import Qt 4.8 is only for 4.8

[andre]

From what I understood at the dev days, the import is going to change to something else completely. I just don't remember exactly to what...

[anselmolsm]

Andre, I saw a mail on the qt-qml mailing list about changing it to import QtQuick 1.0. "Here is the thread":http://lists.trolltech.com/pipermail/qt-qml/2010-September/001102.html.

[anselmolsm]

(I've just given up of using "quote":http://bugreports.qt.nokia.com/browse/QTWEBSITE-93 :-( )

Alexander, ok, your point makes sense.

But the code written with import Qt 4.7 will continue working.

[2beers]

oh. so with other words this will be changed to import QtQuick 1.0 that will be something like qt 4.7.x compatible .
using import QtQuick 1.0 with qt 4.7.0 will work on qt 4.7.x, but no way around (of course) .

But what about import QtQuick 1.0 with qt 4.8?

[2beers]

I also found something on bugreports: "http://bugreports.qt.nokia.com/browse/QTBUG-13451":http://bugreports.qt.nokia.com/browse/QTBUG-13451
that might help us solving this puzzle :)

[mbrasser]

When 4.8 is released, the plan is that you will be able to continue using old import statements, or switch to new import statements if you want to use any of the new features provided.

The reason QtQuick 1.0 was introduced was to decouple QML versioning from Qt versioning. That will hopefully allow us to add new properties, etc within a minor release (e.g. 4.7), rather than having to wait for the next minor release (e.g. 4.8). This flexibility is important because QML is a new technology -- I think its natural that it grows at a different rate from Qt as a whole, which is overall quite mature.

Regards,
Michael