Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

One of the reasons to use QVariant is that it's usually what is needed to connect a C++ signal to a QML function or to use invokeMethod, I could only ever get this to work by passing all arguments as QVariants. See for example:

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

I'm certain that it's possible. I suspect the reason why the code used QVariant is that when it was originally written (in Qt 4.7 days, IIRC), QJSValue didn't exist, and it simply hasn't been ported to newer interfaces since then. Without knowing too much about the QML bindings in QtPIM, I am

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On quarta-feira, 28 de setembro de 2016 15:42:06 PDT Simon Hausmann wrote: > I don't think the QVariant interface is deprecated, but it just inherently > unsuitable for JavaScript specific things such as distinguishing undefined > from null or storing function closures. That is why the engine

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

...@intel.com Sent: September 28, 2016 17:37 To: development@qt-project.org Subject: Re: [Development] Behaviour change in QML in Qt 5.8 regarding null On quarta-feira, 28 de setembro de 2016 08:54:10 PDT Simon Hausmann wrote: > Hi, > > Ok, let me clarify: When the JavaScript engine wants to map

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On quarta-feira, 28 de setembro de 2016 08:54:10 PDT Simon Hausmann wrote: > Hi, > > Ok, let me clarify: When the JavaScript engine wants to map a JS null value > to a QVariant, it used to use > > QVariant(QMetaType::VoidStar, (void *)0); > > and now uses > >

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On Wednesday 28 September 2016, Olivier Goffart wrote: > > int main() { > QVariant v1 = QVariant::fromValue(nullptr); > QVariant v2 = QVariant::fromValue(nullptr); > qDebug() << v1.isNull() << v2.isNull() << (v1 == v2) << (v2 == v1); > qDebug() << v2.canConvert()

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On Mittwoch, 28. September 2016 10:39:42 CEST Allan Sandfeld Jensen wrote: > On Wednesday 28 September 2016, Thiago Macieira wrote: > > On quarta-feira, 28 de setembro de 2016 01:22:33 PDT Allan Sandfeld Jensen > > > > wrote: > > > > QVariant::fromValue(nullptr).isNull() == false > > > >

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

cieira <thiago.macie...@intel.com> Sent: Tuesday, September 27, 2016 11:59:50 PM To: development@qt-project.org Subject: Re: [Development] Behaviour change in QML in Qt 5.8 regarding null On terça-feira, 27 de setembro de 2016 18:22:34 PDT Simon Hausmann wrote: > I'm fairly sure we used QVa

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On Wednesday 28 September 2016, Thiago Macieira wrote: > On quarta-feira, 28 de setembro de 2016 01:22:33 PDT Allan Sandfeld Jensen > > wrote: > > > QVariant::fromValue(nullptr).isNull() == false > > > QVariant(QMetaType::Nullptr).isNull() == true > > > > And QVariant(nullptr) doesn't compile. >

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On quarta-feira, 28 de setembro de 2016 01:22:33 PDT Allan Sandfeld Jensen wrote: > > QVariant::fromValue(nullptr).isNull() == false > > QVariant(QMetaType::Nullptr).isNull() == true > > And QVariant(nullptr) doesn't compile. > > We should probably fix the fromValue constructor. I don't think

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On Tuesday 27 September 2016, Thiago Macieira wrote: > On terça-feira, 27 de setembro de 2016 18:22:34 PDT Simon Hausmann wrote: > > I'm fairly sure we used QVariant(QMetaType::VoidStar); > > Can you guarantee that the only time the QML engine generates null > QVariants is for null JS Values?

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On terça-feira, 27 de setembro de 2016 18:22:34 PDT Simon Hausmann wrote: > I'm fairly sure we used QVariant(QMetaType::VoidStar); Can you guarantee that the only time the QML engine generates null QVariants is for null JS Values? That is, no null QStrings, null QVariantLists, null

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

I'm fairly sure we used QVariant(QMetaType::VoidStar); Simon From: thiago.macie...@intel.com Sent: September 27, 2016 19:26 To: development@qt-project.org Subject: Re: [Development] Behaviour change in QML in Qt 5.8 regarding null On terça-feira, 27 de setembro de 2016 09:31:14 PDT Thiago

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On terça-feira, 27 de setembro de 2016 09:31:14 PDT Thiago Macieira wrote: > On terça-feira, 27 de setembro de 2016 15:29:16 PDT Simon Hausmann wrote: > > That said, I think it can be written without #ifdef perhaps by using > > QVariant::isNull() ? > > > > > > (QVariant(nullptr) maps to isNull()

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On terça-feira, 27 de setembro de 2016 15:29:16 PDT Simon Hausmann wrote: > That said, I think it can be written without #ifdef perhaps by using > QVariant::isNull() ? > > > (QVariant(nullptr) maps to isNull() as well, right? ;-) It should. But QVariant(QString()) [after you bypass C++'s most

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

<development-bounces+simon.hausmann=qt...@qt-project.org> on behalf of Thiago Macieira <thiago.macie...@intel.com> Sent: Tuesday, September 27, 2016 5:04:56 PM To: development@qt-project.org Subject: Re: [Development] Behaviour change in QML in Qt 5.8 regarding null On terça-feira, 27 de

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On terça-feira, 27 de setembro de 2016 11:25:49 PDT Simon Hausmann wrote: > That is exactly the part I'm referring to. Receiving a QVariant from the QML > engine and relying on it to contain a specific type. Well, I would say it's acceptable that the QVariant contain different numeric types as

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

ent@qt-project.org Cc: Simon Hausmann Subject: Re: [Development] Behaviour change in QML in Qt 5.8 regarding null On segunda-feira, 26 de setembro de 2016 09:31:34 PDT Simon Hausmann wrote: > That said, this is not quite the same as changing the return type of a typed > C++ function. QVariant

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On segunda-feira, 26 de setembro de 2016 09:31:34 PDT Simon Hausmann wrote: > That said, this is not quite the same as changing the return type of a typed > C++ function. QVariant is designed > to hold any type and if you receive a QVariant it has always been a little > dangerous to rely on

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

ra <thiago.macie...@intel.com> Sent: Monday, September 26, 2016 9:37:07 AM To: development@qt-project.org Subject: Re: [Development] Behaviour change in QML in Qt 5.8 regarding null On segunda-feira, 26 de setembro de 2016 09:02:58 PDT Jędrzej Nowacki wrote: > On mandag 19. september 2016

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On segunda-feira, 26 de setembro de 2016 09:02:58 PDT Jędrzej Nowacki wrote: > On mandag 19. september 2016 11.14.51 CEST Chris Adams wrote: > > Hi, > > > > Recently, a few unit test failures[1] in the (unreleased) QtPIM module > > showed that the recent change[2] which changes the semantics of

Re: [Development] Behaviour change in QML in Qt 5.8 regarding null

On mandag 19. september 2016 11.14.51 CEST Chris Adams wrote: > Hi, > > Recently, a few unit test failures[1] in the (unreleased) QtPIM module > showed that the recent change[2] which changes the semantics of null > assignment (from JS) to a QVariant Q_PROPERTY can affect existing client > code.

[Development] Behaviour change in QML in Qt 5.8 regarding null

Hi, Recently, a few unit test failures[1] in the (unreleased) QtPIM module showed that the recent change[2] which changes the semantics of null assignment (from JS) to a QVariant Q_PROPERTY can affect existing client code. Certainly, the cases which are affected are most likely edge-cases (that