Re: [Interest] Overriding list properties in QML at initialisation

2019-08-14 Thread Unai IRIGOYEN
Ulf,
I reported the bug here: https://bugreports.qt.io/browse/QTBUG-77529

I will try to propose a fix which has no side effect on Qt3D.

Best regards,

Unai

Le mer. 14 août 2019 à 11:25, Ulf Hermann  a écrit :

> Hello,
>
> > If I create a class with a QQmlListProperty and then initialise it with
> > an array in some QML file, then subclass the QML type in a second QML
> > file and try to override the array there, when creating an instance of
> > the child class, the list contains the arrays concatenated instead of
> > the overriding array.
>
> That's the expected behavior of the default property, e.g. children in
> QQuickItem. Arguably, it should not extend to explicitly setting any
> other list properties.
>
> > In the following example, I would expect the list to contain 2 elements
> > instead of 5. What are your thoughts? Should I fill a bug report and try
> > to provide a fix?
>
> Yes, that would be nice. Keep in mind that the default property should
> still behave the old way, but only if you actually use it as default
> property. The details can be discussed in the report, though.
>
> best regards,
> Ulf
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Re: [Interest] Overriding list properties in QML at initialisation

2019-08-14 Thread Unai IRIGOYEN
Hi Giuseppe,
When you say the QML APIs for Qt3D depend on this behaviour, you are
talking about appending to the default property right? Or are the APIs
depending in the fact that every QQmlListProperty has its contents
concatenated (I can't recall an example where this could be used)?

Best regards,

Unai

Le mer. 14 août 2019 à 18:23, Giuseppe D'Angelo via Interest <
interest@qt-project.org> a écrit :

> Il 14/08/19 11:23, Ulf Hermann ha scritto:
> >> In the following example, I would expect the list to contain 2 elements
> >> instead of 5. What are your thoughts? Should I fill a bug report and try
> >> to provide a fix?
> > Yes, that would be nice. Keep in mind that the default property should
> > still behave the old way, but only if you actually use it as default
> > property. The details can be discussed in the report, though.
>
> This behaviour cannot be changed in a source-compatible way, so it's a
> no-go, unless we also add additional C++/QML syntax for opting in to the
> new behaviour. E.g. the QML APIs for Qt3D massively depend on this.
>
> My 2 c,
> --
> Giuseppe D'Angelo | giuseppe.dang...@kdab.com | Senior Software Engineer
> KDAB (France) S.A.S., a KDAB Group company
> Tel. France +33 (0)4 90 84 08 53, http://www.kdab.com
> KDAB - The Qt, C++ and OpenGL Experts
>
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Re: [Interest] Overriding list properties in QML at initialisation

2019-08-14 Thread Giuseppe D'Angelo via Interest

Il 14/08/19 11:23, Ulf Hermann ha scritto:

In the following example, I would expect the list to contain 2 elements
instead of 5. What are your thoughts? Should I fill a bug report and try
to provide a fix?

Yes, that would be nice. Keep in mind that the default property should
still behave the old way, but only if you actually use it as default
property. The details can be discussed in the report, though.


This behaviour cannot be changed in a source-compatible way, so it's a 
no-go, unless we also add additional C++/QML syntax for opting in to the 
new behaviour. E.g. the QML APIs for Qt3D massively depend on this.


My 2 c,
--
Giuseppe D'Angelo | giuseppe.dang...@kdab.com | Senior Software Engineer
KDAB (France) S.A.S., a KDAB Group company
Tel. France +33 (0)4 90 84 08 53, http://www.kdab.com
KDAB - The Qt, C++ and OpenGL Experts



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Re: [Interest] Overriding list properties in QML at initialisation

2019-08-14 Thread Ulf Hermann
Hello,

> If I create a class with a QQmlListProperty and then initialise it with 
> an array in some QML file, then subclass the QML type in a second QML 
> file and try to override the array there, when creating an instance of 
> the child class, the list contains the arrays concatenated instead of 
> the overriding array.

That's the expected behavior of the default property, e.g. children in 
QQuickItem. Arguably, it should not extend to explicitly setting any 
other list properties.

> In the following example, I would expect the list to contain 2 elements 
> instead of 5. What are your thoughts? Should I fill a bug report and try 
> to provide a fix?

Yes, that would be nice. Keep in mind that the default property should 
still behave the old way, but only if you actually use it as default 
property. The details can be discussed in the report, though.

best regards,
Ulf
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