Build issue on Arch with GCC 14

[mcallegari]

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Apparently Arch did it again. They updated the GCC version and broke QLC+ build (and probably a few other thousand packages out there..) The issue is actually in Qt5:

[  230s] make[3]: Entering directory '/usr/src/packages/BUILD/qlcplus-qt5-git/src/qlcplus-qt5-git-4.13.1.20240511.a1f6cd7/engine/test/bus'
[  230s] g++ -c -pipe -Werror -Wno-unused-local-typedefs -g -Wall -Wextra -D_REENTRANT -fPIC -DQT_GUI_LIB -DQT_TESTLIB_LIB -DQT_CORE_LIB -DQT_TESTCASE_BUILDDIR='"/usr/src/packages/BUILD/qlcplus-qt5-git/src/qlcplus-qt5-git-4.13.1.20240511.a1f6cd7/engine/test/bus"' -I. -I../../../plugins/interfaces -I../../src -I/usr/include/qt -I/usr/include/qt/QtGui -I/usr/include/qt/QtTest -I/usr/include/qt/QtCore -I. -I/usr/lib/qt/mkspecs/linux-g++ -o bus_test.o bus_test.cpp
[  231s] In file included from /usr/include/qt/QtCore/qfuture.h:45,
[  231s]                  from /usr/include/qt/QtCore/QtCore:97,
[  231s]                  from /usr/include/qt/QtTest/QtTestDepends:3,
[  231s]                  from /usr/include/qt/QtTest/QtTest:3,
[  231s]                  from bus_test.cpp:21:
[  231s] /usr/include/qt/QtCore/qfutureinterface.h:284:37: error: template-id not allowed for constructor in C++20 [-Werror=template-id-cdtor]
[  231s]   284 |     explicit QFutureInterface<void>(State initialState = NoState)
[  231s]       |                                     ^~~~~
[  231s] /usr/include/qt/QtCore/qfutureinterface.h:284:37: note: remove the '< >'
[  232s] cc1plus: all warnings being treated as errors
[  232s] make[3]: *** [Makefile:447: bus_test.o] Error 1

The easiest solution is probably to add the flag -Wno-template-id-cdtor but of course it affects the whole QLC+ build. I believe the KDE guys will apply a patch to this quite soon and deliver a Qt 5.15.x build with the fix.

@jeromelebleu have you already seen this? Any suggestion/comment?

[jeromelebleu]

I have a tiny and far memory of template-id error but can't remember for what… And Debian is still using GCC 13, I could not help I guess sorry about that.

I have switched to Qt 6 in the Debian package by the way and it is building and working fine. I just wait for your answer to this message which is asking if you plan to release a 4.13.1 version soon before updating the package - to prevent several patches. Thanks!

[mcallegari]

I am considering to release 4.13.1 but since it takes me a whole day to do it, I don't know when I can do it. I'll try to do it soon. QLC+ v4 on Qt6 is not ready yet. Please don't make any official build with Qt6 yet. I have found a lot of deprecations that broke UI signals therefore making is unusable in some places. (see my latest patch for combo boxes!)

[jeromelebleu]

I am considering to release 4.13.1 but since it takes me a whole day to do it, I don't know when I can do it. I'll try to do it soon.

Thanks! It was not to rush you but just to know if I wait for it or not.

QLC+ v4 on Qt6 is not ready yet. Please don't make any official build with Qt6 yet. I have found a lot of deprecations that broke UI signals therefore making is unusable in some places. (see my latest patch for combo boxes!)

Oops, I missed that, I will rollback to Qt 5 so…

[mcallegari]

This is fixed for now. The problem will probably come out again when cmake is the default for every build platform