Qt6/Fedora build fails with "PythonQt: missing generated wrapper sources"

[codeling]

When trying to build the Slicer pull request for Qt6 support on Fedora 32, I get this error:

CMake Error at CMakeLists.txt:177 (message):
  PythonQt: missing generated wrapper sources for Qt 6.9.

  Expected:
  SLICER_BASE_BUILD_FOLDER/CTK-build/PythonQtGenerator-output-6.9.3/generated_cpp


  Hint: pass -DPythonQt_GENERATED_PATH:PATH=/path/to/generated_cpp

The generated_cpp folder in my case was created inside the PythonQt folder, not inside a PythonQtGenerator-output-6.9.3 folder; though I'm not sure the folder existed at all; this could be somehow triggered by me trying to create the missing generated_cpp folder through running PythonQtGenerator manually.

[codeling]

Trying to build current Slicer main on Fedora 43 now with Qt 6.10.1 (from repositories), I still get

CMake Error at CMakeLists.txt:180 (message):
  PythonQt: missing generated wrapper sources for Qt 6.10.

  Expected:
  /home/bfroehler/devel/Slicer/bin/CTK-build/PythonQtGenerator-output-6.10.1/generated_cpp


  Hint: pass -DPythonQt_GENERATED_PATH:PATH=/path/to/generated_cpp

When I try to run the generator manually in slicerbuilddir/CTK-build/PythonQtGenerator-build, I get:

./PythonQtGenerator --output-directory=slicerbuilddir/CTK-build/PythonQtGenerator-output-6.10.1
Please wait while source files are being generated...
The QTDIR environment variable is not set. Falling back to QLibraryInfo includes path.
Using Qt headers at: "/usr/include/qt6"
Trying to determine Qt version...
Determined Qt version is 96.16.1
Parsing typesystem file [:/trolltech/generator/build_all.txt]
PreProcessing - Generate [.preprocessed.tmp] using [:/trolltech/generator/qtscript_masterinclude.h] and include-paths []
/usr/include/qt6/QtCore/qconfig.h:19: #error: #error "unexpected value for __WORDSIZE macro"
/usr/include/qt6/QtCore/qtversionchecks.h:38: #error: #error Qt major version not 6 or 7
/usr/include/qt6/QtCore/qsystemdetection.h:134: #error: #error "Qt has not been ported to this OS - see http://www.qt-project.org/"
/usr/include/qt6/QtCore/qcompilerdetection.h:431: #error: #error "Qt has not been tested with this compiler - see http://www.qt-project.org/"
/usr/include/qt6/QtCore/qcompilerdetection.h:875: #error: #error "Qt6 requires Unicode string support in both the compiler and the standard library"
/usr/include/qt6/QtCore/qcompilerdetection.h:1319: #error: #error "Qt requires a C++17 compiler"
/usr/include/qt6/QtCore/qtypes.h:272: #error: #error Unsupported platform (unknown value for SIZE_MAX)
/usr/include/qt6/QtCore/qnumeric.h:73: syntax error: failed to evaluate #if condition, division/modulo by zero
Building model using [.preprocessed.tmp]
Classes in typesystem: 0
Generated:
  - header....: 0 (0)
  - impl......: 0 (0)
  - modules...: 0 (0)
  - pri.......: 0 (0)

Done, 4 warnings (2031 known issues)

(so it seems it doesn't find the headers? Or do the #error outputs prevent the creation?)

I also tried manually applying the latest PythonQt fixes for Qt 6.10, this fixes the 96.16.1 output, but still no output is generated.

Does anybody have an idea what's going wrong here?

I think last time (when I first reported this issue) I somehow managed to manually create the files, but I don't remember...

[codeling]

Should I actually report things like this here, or better to https://github.com/MeVisLab/pythonqt ?
Since the way the generator is built and called is a bit specific to the CTK superbuild, and since it seems (for me, currently) to be the thing that most often breaks the slicer superbuild, I was thinking I should report it here.

Sidenote: When trying to build with Qt 6.10.1 on Windows, I currently get 127 errors, many of them with some includes that aren't even part of Qt 6 anymore (like qmatrix.h). So the PythonQt build also seems somewhat brittle - on that Windows system, I also have a Qt 5.10 and that's probably somehow interfering, but I haven't figured out yet how / how I can make PythonQt only look at the 6.10.1 install folder and nothing else.

[jamesobutler]

I have multiple versions of Qt binaries installed (Qt 6.10.1, Qt 6.9.3, 6.8.3, 6.7.3, 5.15.2) and I have not run into any build errors building 3D Slicer main on the Windows platform where I define Qt6_DIR as "C:\Qt\6.10.1\msvc2022_64\lib\cmake\Qt6". My build tools so far have been CMake 3.31.8, Visual Studio 2022 17.14.23 and the v143 toolset. I allow the Slicer superbuild system to pull all dependencies that it wants and choose not to use any system builds.

[lassoan]

@jcfr can you help us out here?

[codeling]

Did some more experiments with manually executing PythonQtGenerator on Windows (opening slicerbuilddir/CTK-build/\PythonQtGenerator-build in a windows command prompt and executing Debug\PythonQtGenerator.exe --output-directory=C:\sl6\dbg\CTK-build\PythonQtGenerator-output-6.10.1).

The build succeeds when I use those manually created files.

For some reasons, the run triggered by the superbuild (the folder with the added "-slicerbuild" suffix in the output below) contains some "extra" files:

$ diff -ur PythonQtGenerator-output-6.10.1-slicerbuild/generated_cpp/ PythonQtGenerator-output-6.10.1/generated_cpp/
Only in PythonQtGenerator-output-6.10.1-slicerbuild/generated_cpp/com_trolltech_qt_multimedia: com_trolltech_qt_multimedia2.cpp
Only in PythonQtGenerator-output-6.10.1-slicerbuild/generated_cpp/com_trolltech_qt_multimedia: com_trolltech_qt_multimedia2.h
Only in PythonQtGenerator-output-6.10.1-slicerbuild/generated_cpp/com_trolltech_qt_multimedia: com_trolltech_qt_multimedia3.cpp
Only in PythonQtGenerator-output-6.10.1-slicerbuild/generated_cpp/com_trolltech_qt_multimedia: com_trolltech_qt_multimedia3.h
Only in PythonQtGenerator-output-6.10.1-slicerbuild/generated_cpp/: com_trolltech_qt_opengl
Only in PythonQtGenerator-output-6.10.1-slicerbuild/generated_cpp/com_trolltech_qt_xml: com_trolltech_qt_xml1.cpp
Only in PythonQtGenerator-output-6.10.1-slicerbuild/generated_cpp/com_trolltech_qt_xml: com_trolltech_qt_xml1.h
Only in PythonQtGenerator-output-6.10.1-slicerbuild/generated_cpp/: com_trolltech_qt_xmlpatterns

So it seems the "correct" files are generated (no difference in the files existing in both versions), but there is something else added.
For qt_multimedia, the extra files aren't even mentioned in the .pri files; and the extra files are the ones containing includes for headers that were removed with Qt6, e.g. qmediacontent.h, and even files for modules removed in Qt 6 are created (xmlpatterns).

Seems like something from a Qt5 version is mixed in there, though I have no idea why or how. Some environment variable maybe? Or something from the Visual Studio Qt extension (where the Qt5 build is a registered version)?

[jamesobutler]

I do not have the Visual Studio Qt extension installed so maybe it is polluting some environment variable that I’m not doing. I exclusively use Qt’s maintenance tool to install and update versions of Qt installed on my system. Are you also building on Windows through command line or CMake-GUI? What are you passing to configure the slicer superbuild?

[codeling]

I'm configuring through CMake-gui on Windows, and setting Slicer_REQUIRED_QT_VERSION=6.10 after first configure.
I'm building through Visual Studio IDE; I install the Qt 6 builds via the maintenance tool, but the Qt 5 builds are a local build (I think Qt doesn't even provide such old builds anymore).

I have now tried running cmake configuration via command line, where the Qt version is specified before the first run via command line ( via -DSlicer_REQUIRED_QT_VERSION=6.10 -DQt6_DIR:PATH=C:/Qt/6.10.1/msvc2022_64/lib/cmake/Qt6 ). Still building via IDE. This did change the outcome slightly (I now get completely outdated PythonQt wrapper sources - several generated files contain #include <qmatrix.h>). This is the same behavior I saw with a colleague of mine today, who uses a very similar machine setup as mine (and also there, we were able to get correct generated sources with a manual generation run).

[jamesobutler]

Yes when using CMake-GUI I manually add Qt6_DIR option before calling to configure the rest of the Slicer project. This is to avoid it by default trying to set up the Qt5 stuff and adding the Qt5_DIR entry that it asks to define. Setting Qt6_DIR first will be necessary until we change the default from Qt5 to Qt6.

[codeling]

I missed something in my previous reply (added it now via edit) - I had already tried the configure via command line cmake with -DSlicer_REQUIRED_QT_VERSION=6.10 -DQt6_DIR:PATH=C:/Qt/6.10.1/msvc2022_64/lib/cmake/Qt6 but the generation still didn't succeed :(.

[codeling]

For Fedora I found the fix: hjmjohnson/mevislab_pythonqt@ce9f365

Maybe this can be incorporated into the superbuild PythonQt CMake script somehow? Not sure how to best check for which distribution we are currently compiling on though, and what others are affected... (Fedora, RHEL, rocky linux ...)?

(further along the way, I am now getting another problem with curl and zstandard - but that's probably even more Fedora-specific)