Public bug reported: Qt 6.6.2 contains a bug in the `QFutureInterface` constructor definition that causes a warning (`template-id-cdtor`) to be emitted by g++ 14.2. In prior versions of Ubuntu, the packaged g++ does not emit a warning for the same code.
The warning causes projects that use `-Werror` to fail compilation. As a workaround, projects may set `-Wno-error=template-id-cdtor`, but this adds complexity to the build chain and requires special build handling for Oracular. A fix was already cherry-picked to Qt 6.6 upstream in March 2024, see * https://bugreports.qt.io/browse/QTBUG-126989 * https://bugreports.qt.io/browse/QTBUG-123153 * https://codereview.qt-project.org/c/qt/qtbase/+/548058 The problematic code was included in many Qt versions and packages, and was fixed in other distributions as well, for example https://bugzilla.redhat.com/show_bug.cgi?id=2280366. ``` $ lsb_release -rd Description: Ubuntu 24.10 Release: 24.10 ``` ``` $ apt-cache policy qt6-base-dev qt6-base-dev: Installed: 6.6.2+dfsg-12 Candidate: 6.6.2+dfsg-12 Version table: *** 6.6.2+dfsg-12 500 500 http://us.archive.ubuntu.com/ubuntu oracular/universe amd64 Packages 100 /var/lib/dpkg/status ``` Expected to happen: When compiling https://github.com/kiwix/kiwix-desktop, the compile should succeed with `-Werror` set. Actually happened: Compile of kiwix-desktop fails when `-Werror` is set: ``` g++ -c -pipe -std=c++17 -Werror -I/usr/local/include -I/usr/include/x86_64-linux-gnu -I/usr/include/p11-kit-1 -O2 -Wall -Wextra -D_REENTRANT -DVERSION=2.4.0 -DQT_DEPRECAT ED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x060000 -DQT_NO_DEBUG -DQT_WEBENGINEWIDGETS_LIB -DQT_PRINTSUPPORT_LIB -DQT_WIDGETS_LIB -DQT_WEBENGINECORE_LIB -DQT_QUICK_LIB - DQT_OPENGL_LIB -DQT_GUI_LIB -DQT_QMLMODELS_LIB -DQT_WEBCHANNEL_LIB -DQT_QML_LIB -DQT_NETWORK_LIB -DQT_QMLINTEGRATION_LIB -DQT_POSITIONING_LIB -DQT_CORE_LIB -I. -Isubproje cts/QtSingleApplication/src -I/usr/include/x86_64-linux-gnu/qt6 -I/usr/include/x86_64-linux-gnu/qt6/QtWebEngineWidgets -I/usr/include/x86_64-linux-gnu/qt6/QtPrintSupport -I/usr/include/x86_64-linux-gnu/qt6/QtWidgets -I/usr/include/x86_64-linux-gnu/qt6/QtWebEngineCore -I/usr/include/x86_64-linux-gnu/qt6/QtQuick -I/usr/include/x86_64-linux- gnu/qt6/QtOpenGL -I/usr/include/x86_64-linux-gnu/qt6/QtGui -I/usr/include/x86_64-linux-gnu/qt6/QtQmlModels -I/usr/include/x86_64-linux-gnu/qt6/QtWebChannel -I/usr/include /x86_64-linux-gnu/qt6/QtQml -I/usr/include/x86_64-linux-gnu/qt6/QtNetwork -I/usr/include/x86_64-linux-gnu/qt6/QtQmlIntegration -I/usr/include/x86_64-linux-gnu/qt6/QtPosit ioning -I/usr/include/x86_64-linux-gnu/qt6/QtCore -I. -I. -I/usr/lib/x86_64-linux-gnu/qt6/mkspecs/linux-g++ -o choiceitem.o src/choiceitem.cpp In file included from /usr/include/x86_64-linux-gnu/qt6/QtCore/qfuture.h:9, from /usr/include/x86_64-linux-gnu/qt6/QtCore/QtCore:106, from /usr/include/x86_64-linux-gnu/qt6/QtNetwork/QtNetworkDepends:3, from /usr/include/x86_64-linux-gnu/qt6/QtNetwork/QtNetwork:3, from src/opdsrequestmanager.h:5, from src/contentmanager.h:7, from src/kiwixapp.h:5, from src/choiceitem.cpp:5: /usr/include/x86_64-linux-gnu/qt6/QtCore/qfutureinterface.h:472:37: error: template-id not allowed for constructor in C++20 [-Werror=template-id-cdtor] 472 | explicit QFutureInterface<void>(State initialState = NoState) | ^~~~~ /usr/include/x86_64-linux-gnu/qt6/QtCore/qfutureinterface.h:472:37: note: remove the ‘< >’ cc1plus: all warnings being treated as errors ``` Removing `<void>` in the constructor at qfutureinterface.h:472 resolves the problem. ** Affects: qt6-base (Ubuntu) Importance: Undecided Status: New ** Description changed: Qt 6.6.2 contains a bug in the `QFutureInterface` constructor definition that causes a warning (`template-id-cdtor`) to be emitted by g++ 14.2. In prior versions of Ubuntu, the packaged g++ does not emit a warning for the same code. The warning causes projects that use `-Werror` to fail compilation. As a workaround, projects may set `-Wno-error=template-id-cdtor`, but this adds complexity to the build chain and requires special build handling for Oracular. - The problem was already cherry-picked to Qt 6.6 upstream in March 2024, - see + A fix was already cherry-picked to Qt 6.6 upstream in March 2024, see * https://bugreports.qt.io/browse/QTBUG-126989 * https://bugreports.qt.io/browse/QTBUG-123153 * https://codereview.qt-project.org/c/qt/qtbase/+/548058 The problematic code was included in many Qt versions and packages, and was fixed in other distributions as well, for example https://bugzilla.redhat.com/show_bug.cgi?id=2280366. ``` $ lsb_release -rd Description: Ubuntu 24.10 Release: 24.10 ``` ``` $ apt-cache policy qt6-base-dev qt6-base-dev: - Installed: 6.6.2+dfsg-12 - Candidate: 6.6.2+dfsg-12 - Version table: - *** 6.6.2+dfsg-12 500 - 500 http://us.archive.ubuntu.com/ubuntu oracular/universe amd64 Packages - 100 /var/lib/dpkg/status + Installed: 6.6.2+dfsg-12 + Candidate: 6.6.2+dfsg-12 + Version table: + *** 6.6.2+dfsg-12 500 + 500 http://us.archive.ubuntu.com/ubuntu oracular/universe amd64 Packages + 100 /var/lib/dpkg/status ``` Expected to happen: When compiling https://github.com/kiwix/kiwix-desktop, the compile should succeed with `-Werror` set. Actually happened: Compile of kiwix-desktop fails when `-Werror` is set: ``` g++ -c -pipe -std=c++17 -Werror -I/usr/local/include -I/usr/include/x86_64-linux-gnu -I/usr/include/p11-kit-1 -O2 -Wall -Wextra -D_REENTRANT -DVERSION=2.4.0 -DQT_DEPRECAT ED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x060000 -DQT_NO_DEBUG -DQT_WEBENGINEWIDGETS_LIB -DQT_PRINTSUPPORT_LIB -DQT_WIDGETS_LIB -DQT_WEBENGINECORE_LIB -DQT_QUICK_LIB - DQT_OPENGL_LIB -DQT_GUI_LIB -DQT_QMLMODELS_LIB -DQT_WEBCHANNEL_LIB -DQT_QML_LIB -DQT_NETWORK_LIB -DQT_QMLINTEGRATION_LIB -DQT_POSITIONING_LIB -DQT_CORE_LIB -I. -Isubproje cts/QtSingleApplication/src -I/usr/include/x86_64-linux-gnu/qt6 -I/usr/include/x86_64-linux-gnu/qt6/QtWebEngineWidgets -I/usr/include/x86_64-linux-gnu/qt6/QtPrintSupport -I/usr/include/x86_64-linux-gnu/qt6/QtWidgets -I/usr/include/x86_64-linux-gnu/qt6/QtWebEngineCore -I/usr/include/x86_64-linux-gnu/qt6/QtQuick -I/usr/include/x86_64-linux- gnu/qt6/QtOpenGL -I/usr/include/x86_64-linux-gnu/qt6/QtGui -I/usr/include/x86_64-linux-gnu/qt6/QtQmlModels -I/usr/include/x86_64-linux-gnu/qt6/QtWebChannel -I/usr/include /x86_64-linux-gnu/qt6/QtQml -I/usr/include/x86_64-linux-gnu/qt6/QtNetwork -I/usr/include/x86_64-linux-gnu/qt6/QtQmlIntegration -I/usr/include/x86_64-linux-gnu/qt6/QtPosit ioning -I/usr/include/x86_64-linux-gnu/qt6/QtCore -I. -I. -I/usr/lib/x86_64-linux-gnu/qt6/mkspecs/linux-g++ -o choiceitem.o src/choiceitem.cpp In file included from /usr/include/x86_64-linux-gnu/qt6/QtCore/qfuture.h:9, - from /usr/include/x86_64-linux-gnu/qt6/QtCore/QtCore:106, - from /usr/include/x86_64-linux-gnu/qt6/QtNetwork/QtNetworkDepends:3, - from /usr/include/x86_64-linux-gnu/qt6/QtNetwork/QtNetwork:3, - from src/opdsrequestmanager.h:5, - from src/contentmanager.h:7, - from src/kiwixapp.h:5, - from src/choiceitem.cpp:5: + from /usr/include/x86_64-linux-gnu/qt6/QtCore/QtCore:106, + from /usr/include/x86_64-linux-gnu/qt6/QtNetwork/QtNetworkDepends:3, + from /usr/include/x86_64-linux-gnu/qt6/QtNetwork/QtNetwork:3, + from src/opdsrequestmanager.h:5, + from src/contentmanager.h:7, + from src/kiwixapp.h:5, + from src/choiceitem.cpp:5: /usr/include/x86_64-linux-gnu/qt6/QtCore/qfutureinterface.h:472:37: error: template-id not allowed for constructor in C++20 [-Werror=template-id-cdtor] - 472 | explicit QFutureInterface<void>(State initialState = NoState) - | ^~~~~ + 472 | explicit QFutureInterface<void>(State initialState = NoState) + | ^~~~~ /usr/include/x86_64-linux-gnu/qt6/QtCore/qfutureinterface.h:472:37: note: remove the ‘< >’ cc1plus: all warnings being treated as errors ``` - - Removing `<void>` in the constructor at qfutureinterface.h:472 resolves the problem. + Removing `<void>` in the constructor at qfutureinterface.h:472 resolves + the problem. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2092147 Title: QFutureInterface produces warning on g++ 14.2 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qt6-base/+bug/2092147/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
