Debian build - error: undefined reference to 'QQmlWebChannel'

professorkaos64

System notes:

Target OS: Debian Jessie
Build system: pbuilder / clean environment

Description

I am having a heck of a time trying to build QtWebengine. I have built all the prior packages needed thus far, backporting the main packages (minus docs pkgs, which I will do later) with symbols. The only suspect I can see here that could be build wrong is qtwebchannel, which I did a "catch-all" build with qmake, no sub-packages. This was in order to satisfy qmake error output on qtwebengine reporting there was no qml or qtwebchannel.

It's frustrating a bit, since I got so close! If there are any details you wish to see beyond what is given and linked below, please let me know. My package pool is listed if you wish to extract any debs to help. I really appreciate any guidance you can give me.

Code snippet

api/qquickwebengineview.cpp:1127: error: undefined reference to 'QQmlWebChannel::QQmlWebChannel(QObject*)'
collect2: error: ld returned 1 exit status
Makefile:168: recipe for target '../../lib/libQt5WebEngine.so.5.6.1' failed
make[4]: *** [../../lib/libQt5WebEngine.so.5.6.1] Error 1
make[4]: Leaving directory '/build/qtwebengine-5.6.0+git+bsos/src/webengine'

Relevant links and logs:

Full build log
Build script (not so much relevant, but here it is):
Debian files
My package pool
Qt packages I have already built

kshegunov

@professorkaos64
Hello,
Sadly I have no experience with puilder or QtWebEngine, but a quick view at the source shows there's no line 1127 in qquickwebengineview.cpp (probably the error occurs in one of the files generated by moc). Still it's curious that a constructor can't be found.

Can you verify you've built Qt5WebChannel (I can't see that you have in the build log)?

PS.
This seems quite a complicated way of getting packages, are you a maintainer?

Kind regards,

professorkaos64

Hi @kshegunov , I am backporting Qt packages to have a Debianized version for use with some experiemental projects for Linux I wish to build packages for (like PlexMediaPlayer). I have built QtWebChannel with a typical 'qmake' call in dh_auto_configure. That is my suspicion though, that it was built incorrectly. No, I am not a maintainer officially. I have a 3rd party repo where I build packages for Jessie/SteamOS Brewmaster.

QtWebChannel build script / debian files

kshegunov

@professorkaos64
I see, my point stands, however. I still can't find a line where the QtWebChannel module is built in your full build log.
It's unpacked:

Unpacking qtwebchannel:amd64 (5.6.0+git+bsos-1) ...

Set up:

Setting up qtwebchannel:amd64 (5.6.0+git+bsos-1) ...

And then used:

g++ -c -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2 -O2 -std=c++1y -fno-exceptions -Wall -W -D_REENTRANT -fPIC -DQT_NO_TSLIB -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_NO_DEBUG -DQT_WEBENGINECORE_LIB -DQT_QUICK_LIB -DQT_GUI_LIB -DQT_QML_LIB -DQT_NETWORK_LIB -DQT_WEBCHANNEL_LIB -DQT_CORE_LIB -I. -I../core -I../../include -I../../include/QtWebEngineCore -isystem /usr/include/x86_64-linux-gnu/qt5 -isystem /usr/include/x86_64-linux-gnu/qt5/QtQuick -isystem /usr/include/x86_64-linux-gnu/qt5/QtGui -isystem /usr/include/x86_64-linux-gnu/qt5/QtQml -isystem /usr/include/x86_64-linux-gnu/qt5/QtNetwork -isystem /usr/include/x86_64-linux-gnu/qt5/QtWebChannel -isystem /usr/include/x86_64-linux-gnu/qt5/QtCore -I.moc -isystem /usr/include/libdrm -I/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++-64 -o .obj/main.o main.cpp
g++ -Wl,-z,relro -Wl,--as-needed -Wl,--gc-sections -Wl,-O1 -fuse-ld=gold -Wl,--enable-new-dtags -Wl,-rpath-link,/build/qtwebengine-5.6.0+git+bsos/lib -Wl,-rpath-link,/usr/lib/x86_64-linux-gnu -o ../../libexec/QtWebEngineProcess .obj/main.o   -L/build/qtwebengine-5.6.0+git+bsos/lib -lQt5WebEngineCore -lQt5Quick -lQt5Gui -lQt5Qml -lQt5Network -lQt5WebChannel -lQt5Core -lGL -lpthread 
make[4]: Leaving directory '/build/qtwebengine-5.6.0+git+bsos/src/process'
cd webengine/ && ( test -e Makefile || /usr/lib/x86_64-linux-gnu/qt5/bin/qmake /build/qtwebengine-5.6.0+git+bsos/src/webengine/webengine.pro CONFIG+=release -o Makefile ) && make -f Makefile 
make[4]: Entering directory '/build/qtwebengine-5.6.0+git+bsos/src/webengine'
perl /usr/lib/x86_64-linux-gnu/qt5/mkspecs/features/data/unix/findclasslist.pl < QtWebEngine.version.in > QtWebEngine.version
g++ -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2 -O2 -std=c++1y -fvisibility=hidden -fvisibility-inlines-hidden -fno-exceptions -Wall -W -D_REENTRANT -fPIC -DQT_NO_TSLIB -DQT_BUILD_WEBENGINE_LIB -DQT_BUILD_WEBENGINE_LIB -DQT_BUILDING_QT -DQT_NO_CAST_TO_ASCII -DQT_ASCII_CAST_WARNINGS -DQT_MOC_COMPAT -DQT_USE_QSTRINGBUILDER -DQT_DEPRECATED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x050000 -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_NO_DEBUG -DQT_WEBENGINECORE_LIB -DQT_QUICK_LIB -DQT_GUI_LIB -DQT_QML_LIB -DQT_NETWORK_LIB -DQT_WEBCHANNEL_LIB -DQT_CORE_LIB -DQT_QUICK_LIB -DQT_GUI_LIB -DQT_QML_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -I. -I. -Iapi -I../core -I../core/api -I../../include -I../../include/QtWebEngine -I../../include/QtWebEngine/5.6.1 -I../../include/QtWebEngine/5.6.1/QtWebEngine -I../../include/QtWebEngineCore -isystem /usr/include/x86_64-linux-gnu/qt5 -isystem /usr/include/x86_64-linux-gnu/qt5/QtQuick -isystem /usr/include/x86_64-linux-gnu/qt5/QtGui -isystem /usr/include/x86_64-linux-gnu/qt5/QtQml -isystem /usr/include/x86_64-linux-gnu/qt5/QtNetwork -isystem /usr/include/x86_64-linux-gnu/qt5/QtWebChannel -isystem /usr/include/x86_64-linux-gnu/qt5/QtCore -isystem /usr/include/x86_64-linux-gnu/qt5/QtQuick/5.6.0 -isystem /usr/include/x86_64-linux-gnu/qt5/QtQuick/5.6.0/QtQuick -isystem /usr/include/x86_64-linux-gnu/qt5/QtGui/5.6.0 -isystem /usr/include/x86_64-linux-gnu/qt5/QtGui/5.6.0/QtGui -isystem /usr/include/x86_64-linux-gnu/qt5/QtQml/5.6.0 -isystem /usr/include/x86_64-linux-gnu/qt5/QtQml/5.6.0/QtQml -isystem /usr/include/x86_64-linux-gnu/qt5/QtCore/5.6.0 -isystem /usr/include/x86_64-linux-gnu/qt5/QtCore/5.6.0/QtCore -I.moc -isystem /usr/include/libdrm -I/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++-64 -x c++-header -c ../../include/QtWebEngine/QtWebEngineDepends -o .pch/Qt5WebEngine.gch/c++

I don't see a build step for it, so how can you link against it?:

g++ -Wl,-z,relro -Wl,--as-needed -Wl,--no-undefined -Wl,--version-script,QtWebEngine.version -Wl,-O1 -fuse-ld=gold -Wl,--enable-new-dtags -Wl,-rpath-link,/build/qtwebengine-5.6.0+git+bsos/lib -shared -Wl,-Bsymbolic-functions -Wl,-soname,libQt5WebEngine.so.5 -o libQt5WebEngine.so.5.6.1 .obj/qquickwebenginecertificateerror.o .obj/qquickwebenginedownloaditem.o .obj/qquickwebenginehistory.o .obj/qquickwebengineloadrequest.o .obj/qquickwebenginenavigationrequest.o .obj/qquickwebenginenewviewrequest.o .obj/qquickwebengineprofile.o .obj/qquickwebenginescript.o .obj/qquickwebenginesettings.o .obj/qquickwebenginesingleton.o .obj/qquickwebengineview.o .obj/qtwebengineglobal.o .obj/render_widget_host_view_qt_delegate_quick.o .obj/render_widget_host_view_qt_delegate_quickwindow.o .obj/ui_delegates_manager.o .obj/moc_qquickwebenginecertificateerror_p.o .obj/moc_qquickwebenginedownloaditem_p.o .obj/moc_qquickwebenginehistory_p.o .obj/moc_qquickwebengineloadrequest_p.o .obj/moc_qquickwebenginenavigationrequest_p.o .obj/moc_qquickwebenginenewviewrequest_p.o .obj/moc_qquickwebengineprofile.o .obj/moc_qquickwebenginescript_p.o .obj/moc_qquickwebenginesettings_p.o .obj/moc_qquickwebenginesingleton_p.o .obj/moc_qquickwebengineview_p.o .obj/moc_qquickwebengineview_p_p.o .obj/moc_render_widget_host_view_qt_delegate_quick.o .obj/moc_ui_delegates_manager.o  -L/build/qtwebengine-5.6.0+git+bsos/lib -lQt5WebEngineCore -lQt5Quick -lQt5Gui -lQt5Qml -lQt5Network -lQt5WebChannel -lQt5Core -lpthread -lQt5Quick -lQt5Gui -lQt5Qml -lQt5Network -lQt5Core -lGL

professorkaos64

Are you inferring I need to build webchannel inside debian/rules so it can be statically linked? Clone the main Qt5 source, init the repository, and do so? Webchannel is in fact installed at /usr/include/x86_64-linux-gnu/qt5/QtWebChannel, as I am in a root shell (from a C10 shell hook when the build fails) inside the chroot checking things out. Sorry I am misunderstanding you.

kshegunov

@professorkaos64 said:

Are you inferring I need to build webchannel inside debian/rules

Yes, I believe you should.

so it can be statically linked?

Nope, it's linked dynamically, but linked nonetheless.

Clone the main Qt5 source, init the repository, and do so?

Yes, the same way you're building all the other modules you're using (as can be seen from your build log).

Webchannel is in fact installed at /usr/include/x86_64-linux-gnu/qt5/QtWebChannel

These are the headers, not the binaries, but I can't tell, is this path before or after chrooting for the build? It should be available to the compiler/linker after changing the root.

Sorry I am misunderstanding you.

As I said, I'm not well versed in the process you're using for building, however, I just observed in your build log that the QtWebChannel is not built alongside all your other Qt/Qt modules.

I hope this helps.
Kind regards.

professorkaos64

I had a look at the OpenSUSE 5.6 spec file for this. My other attempt at bulding qtwebchannel into a proper set of install files tried to mimic this. If I don't provid install files, everything get's installed to /lib and /include, not /usr/lib... and /usr/include/.... which seemed strange since the prefix is usr/ for my qtbase install and all other modules built fine.

What part of that spec file is the binary I can double check? Where should qtwebchannel be installing? I know my catch all package installs the headers, but what piece of that install spec denotes the binary for me to check that it built?

kshegunov

@professorkaos64

I had a look at the OpenSUSE 5.6 spec file for this. My other attempt at bulding qtwebchannel into a proper set of install files tried to mimic this. If I don't provid install files, everything get's installed to /lib and /include, not /usr/lib... and /usr/include/.... which seemed strange since the prefix is usr/ for my qtbase install and all other modules built fine.
What part of that spec file is the binary I can double check? Where should qtwebchannel be installing? I know my catch all package installs the headers, but what piece of that install spec denotes the binary for me to check that it built?

I'm sorry but I really can't say, I have no idea what that file is or how it's used. It looks like a shell script, but I don't recognize the interpreter. That said, I'd first look at the chrooted /usr/lib (or /lib) if the Qt5WebChannel.so is present, if not it should somehow be made available to the linker, either by providing a symbolic link to it's location or by copying the binary from it's build location. I'm sorry I can't be more specific, but I reiterate I haven't built anything this way, and only observed that there's no build step for said module.

PS. I'm sorry for the delay, I was pretty busy these two days.