Build issue with Qt 5.2.1

[laanwj]

It is no longer possible to build the GUI with Qt 5.2.1, which is on Ubuntu Trusty:

  CXX      qt/test/qt_test_test_bitcoin_qt-util.o
qt/test/util.cpp: In function ‘void ConfirmMessage(QString*, int)’:
qt/test/util.cpp:21:24: error: no matching function for call to ‘QTimer::singleShot(int&, FunctionCallback<ConfirmMessage(QString*, int)::__lambda0>*, void (Callback::*)())’
     }), &Callback::call);
                        ^
qt/test/util.cpp:21:24: note: candidates are:
In file included from /usr/include/qt5/QtCore/QTimer:1:0,
                 from qt/test/util.cpp:5:
/usr/include/qt5/QtCore/qtimer.h:81:17: note: static void QTimer::singleShot(int, const QObject*, const char*)
     static void singleShot(int msec, const QObject *receiver, const char *member);
                 ^
/usr/include/qt5/QtCore/qtimer.h:81:17: note:   no known conversion for argument 3 from ‘void (Callback::*)()’ to ‘const char*’
/usr/include/qt5/QtCore/qtimer.h:82:17: note: static void QTimer::singleShot(int, Qt::TimerType, const QObject*, const char*)
     static void singleShot(int msec, Qt::TimerType timerType, const QObject *receiver, const char *member);
                 ^
/usr/include/qt5/QtCore/qtimer.h:82:17: note:   candidate expects 4 arguments, 3 provided

Not a high-priority issue, but I think we either need to fix this or add minimum Qt version check (to what?).

[fanquake]

From memory there is a qt5.2 workaround in the tests somewhere? However this may be related to the recent compile time changes.

…

On Mon, 27 Aug 2018 at 18:23, Wladimir J. van der Laan < ***@***.***> wrote: It is no longer possible to build the GUI with Qt 5.2.1, which is on Ubuntu Trusty: CXX qt/test/qt_test_test_bitcoin_qt-util.o qt/test/util.cpp: In function ‘void ConfirmMessage(QString*, int)’: qt/test/util.cpp:21:24: error: no matching function for call to ‘QTimer::singleShot(int&, FunctionCallback<ConfirmMessage(QString*, int)::__lambda0>*, void (Callback::*)())’ }), &Callback::call); ^ qt/test/util.cpp:21:24: note: candidates are: In file included from /usr/include/qt5/QtCore/QTimer:1:0, from qt/test/util.cpp:5: /usr/include/qt5/QtCore/qtimer.h:81:17: note: static void QTimer::singleShot(int, const QObject*, const char*) static void singleShot(int msec, const QObject *receiver, const char *member); ^ /usr/include/qt5/QtCore/qtimer.h:81:17: note: no known conversion for argument 3 from ‘void (Callback::*)()’ to ‘const char*’ /usr/include/qt5/QtCore/qtimer.h:82:17: note: static void QTimer::singleShot(int, Qt::TimerType, const QObject*, const char*) static void singleShot(int msec, Qt::TimerType timerType, const QObject *receiver, const char *member); ^ /usr/include/qt5/QtCore/qtimer.h:82:17: note: candidate expects 4 arguments, 3 provided Not a high-priority issue, but I think we either need to fix this or add minimum Qt version check (to what?). — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#14078>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AA0t8jxekQ_jo2GDicGRRiL8H3JTc2Dwks5uU8ingaJpZM4WNiyw> .

[laanwj]

I can only find that there's a qt 5.3 workaround in nested RPC tests:

src/qt/test/rpcnestedtests.cpp:#if QT_VERSION >= 0x050300

[maflcko]

This is only on master (due to the change to the new connect syntax). cc @promag

[ryanofsky]

The code was only changed to use QTimer::singleShot for compatibility with Qt4. Since compatibility is no longer needed, probably a good way to fix the issue and simplify the code is just to revert #10098.

[promag]

I'll fix it unless someone is already on it.

[laanwj]

@ryanofsky makes sense!

@promag thanks, but I think it makes sense if I do it, as I have the trusty VM to test with

[laanwj]

reverting got past the first error, but there's more, unfortunately,

qt/bitcoin.cpp: In member function ‘void BitcoinApplication::initializeResult(bool)’:
qt/bitcoin.cpp:509:71: error: no matching function for call to ‘QTimer::singleShot(int, PaymentServer*&, void (PaymentServer::*)())’
         QTimer::singleShot(100, paymentServer, &PaymentServer::uiReady);
                                                                       ^
qt/bitcoin.cpp:509:71: note: candidates are:
In file included from /usr/include/qt5/QtCore/QTimer:1:0,
                 from qt/bitcoin.cpp:51:
/usr/include/qt5/QtCore/qtimer.h:81:17: note: static void QTimer::singleShot(int, const QObject*, const char*)
     static void singleShot(int msec, const QObject *receiver, const char *member);
                 ^
/usr/include/qt5/QtCore/qtimer.h:81:17: note:   no known conversion for argument 3 from ‘void (PaymentServer::*)()’ to ‘const char*’
/usr/include/qt5/QtCore/qtimer.h:82:17: note: static void QTimer::singleShot(int, Qt::TimerType, const QObject*, const char*)
     static void singleShot(int msec, Qt::TimerType timerType, const QObject *receiver, const char *member);
                 ^
/usr/include/qt5/QtCore/qtimer.h:82:17: note:   candidate expects 4 arguments, 3 provided

[ryanofsky]

Probably you need to make the same change in the other places: avoid QTimer::singleShot by
instantiating a QTimer and calling QObject::connect on it. You could wrap this up in a convenience function if it's a repeating pattern.

Another option would be to go back to using the SLOT macro, but this might be less desirable long term.

[laanwj]

If this affects all uses of singleShot, that's quite a lot:

src/qt/bitcoin.cpp:        QTimer::singleShot(100, paymentServer, &PaymentServer::uiReady);
src/qt/bitcoingui.cpp:                QTimer::singleShot(0, this, &BitcoinGUI::hide);
src/qt/bitcoingui.cpp:                QTimer::singleShot(0, this, &BitcoinGUI::show);
src/qt/optionsdialog.cpp:        QTimer::singleShot(10000, this, &OptionsDialog::clearStatusLabel);
src/qt/test/util.cpp:    QTimer::singleShot(msec, makeCallback([text](Callback* callback) {
src/qt/test/wallettests.cpp:    QTimer::singleShot(0, makeCallback([text, cancel](Callback* callback) {

Not sure that's worth it.

Looks like the QTimer::singleShot(int msec, const QObject *receiver, PointerToMemberFunction method) function was introduced in Qt 5.4.

According to wikipedia, Qt 5.4 was released on 10 December 2014. It isn't even under official support anymore.

[promag]

Ref #13478.

[promag]

Since this is master only, can we bump Qt to 5.5? Trusty EOL is April 2019.