Hi Dmitry, On Wed August 7 2019 11:27:00 Dmitry Shachnev wrote: > I agree with Lisandro that for many people it will be enough to just run > the examples, not (re-)compile them.
The Qt examples are not like glxgears. They are fundamentally different. They are not to demonstrate how pretty Qt looks or how fast it runs. If their purpose was to demonstrate how pretty Qt looks there might be a dozen examples, not hundreds of examples covering every aspect of Qt programming. If their purpose was to demonstrate how pretty Qt looks there would not be source files and header files and project files and images and resources and every thing else needed to build ... except the dependencies. If someone wants to see Qt in action they can login to KDE. Qt is a tool for programmers. Qt examples are for programmers to build. When they don't build they are broken. Lisandro wrote: > Tell upstream that. It's the Qt build system that does exactly that: > provide compiled binaries. The orig.tar.xz do not include the precompiled binaries. Of course debuild can build the binaries with all the necessary dependencies installed, but it was Debian's decision to ship precompiled binaries in the Debian examples packages. That was not Qt's decision. And it was Debian's decision to ship the examples without the dependencies so they won't build for programmers even though they build for debuild. That is unkind! But just as an aside let's pretend for a moment that Lisandro is correct. Let's try running one of the precompiled binaries. Go ahead on a clean system and install qtwebview5-examples which is the package I just finished testing. Then: $ /usr/lib/x86_64-linux-gnu/qt5/examples/webview/minibrowser/minibrowser QQmlApplicationEngine failed to load component qrc:/main.qml:53 module "QtWebView" is not installed Sadly I don't have the time to file reports on all these examples runtime bugs. My goal is in a couple of weeks to document the problems preventing Qt examples from building, together with fixes that Qt programmers can use to work around the problems and that future DDs can use to fix the problems. > So we should not add these > dependencies, at most we can add some of these packages to Suggests. The necessary packages are not essential so they must be dependencies. That is the way Debian works. These packages are fundamentally broken without qt5-default and c++-compiler and make and an eclectic mix of auxiliary packages. Programmers should be able to install the examples packages and have them compile without hunting for missing dependencies. That's the whole point of using a distro. Nobody is going to install the examples unless they want to compile them. They is no joy in staring at an example widget that does nothing unless you actually intend to build upon it in your own programming. Or go ahead and run /usr/lib/x86_64-linux-gnu/qt5/examples/corelib/threads/waitconditions/waitconditions and tell me what you learned from merely running it. > But see below: > > On Mon, Aug 05, 2019 at 06:53:52AM -0700, Mike Bird wrote: > > A directory of files and several dependencies are missing from > > qtbase5-examples. Here is how to fix it. > > > > (1) In the source package, file "examples/vulkan/vulkan.pro", at the > > end add a blank line and then a line containing only > > "EXAMPLE_FILES = shared" (without the quotes). The resut will > > end up looking like the tail of file "cat > > examples/network/network.pro". > > This sounds like an upstream issue. Please file a bug on bugreports.qt.io > or directly submit the patch to codereview.qt-project.org, explaining why > this change is needed With all the various "rm -rf" in debian/rules I would not feel comfortable filing bugs upstream against Debian Qt packages. > (you did not explain your problem here). Without the "shared" directory, a lot of the examples cannot compile. > > (2) Add the following miscellaneous dependencies: > > qt5-default c++-compiler make qtbase5-private-dev libqt5opengl5-dev > > As Lisandro explained, nothing should really depend on qt5-default. > > In fact, Lintian even has a warning for this: > https://wiki.debian.org/Lintian/Tags/depends-on-metapackage The lintian warning has two aspects. Debian internally should be exporting QT_SELECT=qt5 in debian/rules. That is correct and Debian does. But the lintian warning also assumes that qt5-default is a metapackage which if depended upon restricts users ability to uninstall stuff. But qt5-default depends only on qtbase5-dev and qtchooser. Yet qtbase5-dev depends on qtchooser, and qtchooser is not much use without qtbase5-dev or qtbase4-dev, so the lintian warning is inappropriate and should be removed or at least overridden for Qt5 examples. Without qt5-default the examples break with: $ qmake /usr/lib/x86_64-linux-gnu/qt5/examples/webview/webview.pro qmake: could not find a Qt installation of '' Not very helpful and when you Google it you'll be told to install qt5-default, which is what should have been brought in as a dependency by the distro. > And I think people who really need to *compile* examples will have g++ and > qmake/make installed. If they are missing it is quite easy to figure out > how to install them. That's not how dependencies work in Debian. If you want to make g++ essential we can have that conversation but some people might prefer clang. Meanwhile anyone who wants to use Qt examples as they were intended - which is to help with programming and not for staring at widgets which don't do anything - is going to need the dependencies I have listed. The fixes are simple. Someone could have fixed them in the time we've been discussing this. What takes time is figuring out what is wrong. And it makes no sense that every single Qt programmer should have to go through that process. AND NOW FOR THE IMPORTANT PART ... I'm not asking you to fix these bugs. I'm not asking Lisandro to fix these bugs. I recognize that Debian is a do-ocracy. I'm asking you to re-open this bug and to leave the other related bugs open. I'm putting a lot of work into identifying the problems and workarounds. This information is valuable to future DDs who might want to fix these bugs. And this information is valuable to Qt programmers using Debian who wonder why the examples are broken. When configured correctly the examples build directly from qtcreator, or from the command line somewhat as follows: mkdir foo && cd foo && qmake /usr/lib/.../foo.pro && make That is how the Qt examples are meant to work. There is no reason why every single Qt programmer should have to spend two weeks figuring out the workarounds when they can be kept here in readily accessible form in open bug reports until some DD decides he or she wants to fix the problems. Thank you for reading this far. Please re-open this bug and leave the related bugs open to provide information for Qt programmers and future DDs. --Mike
