[Development] Which changes are suitable for 5.6?

[Thiago Macieira]

On sábado, 13 de agosto de 2016 18:08:16 PDT Gunnar Roth wrote:
> 1. category is just adding code, which does not influence current
> code. 
> a. adding qAsConst in qgolbal.h. That is actually something i really
> like to have in qt 5.6, because it is very useful and has no risk. 

Except that it's impossible. For the feature to work, we need rvalue 
references to prevent wrong use. We can't do that in 5.6 because it doesn't 
require C++11.

> b. adding EditorFont to qplatformtheme.h enumeration ,has  also no risk. 

Not allowed per Qt API compatibility promise: code compiled with Qt 5.6.x must 
run just fine with Qt 5.6.y even if y < x.

> c. protect cleanup of QQmlEngine when removing from QQmlDebugConnector in
> destructor, because quickcontrols2 instantiates it in  a way that it is not
> registered, but on cleanup crashes when removing as there is no check if it
> was added at all. I consider that a bug in Qt 5.6.1

I have no idea about this one.

>   d. adding QQuickItem::isAncestorOf function to qquickitem.* has also no
> risk. 

But violates Qt API policy even worse than adding an enum because it would 
cause dynamic linker errors.

> e. adding Q_QUICK_PRIVATE_EXPORT to  QQuickStateAction  class in
> qquickstate_p.h

That's ok.

> 2. category is enhancing code but also modifies existing code.
> 
>   a.  enhance qml module lookup behavior in a way making things a lot
> easier.
> 
>        qqmlimport.* is changed ( by merging simply the code from 5.7 to do a
> lookup like this: For example, QtQml.Models 2.0:
>        - base/QtQml/Models.2.0/qmldir
>        - base/QtQml.2.0/Models/qmldir
>        - base/QtQml/Models.2/qmldir
>        - base/QtQml.2/Models/qmldir
>        - base/QtQml/Models/qmldir
>       This is very convenient. quickcontrols2 works without that but only
> with the default style. quickcontrols1 is jumping through hoops to achieve
> similar without change qtdeclarative.

No idea about this.

>   b. adding MovementDirection property  to QQuickPathView, i just copied
> qquickpathview.* from qt 5.7. I assume a low risk, but qt 5.7 has the same
> risk then.

API policy violation.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center