[Debian-med-packaging] Bug#1148945: camitk: autopkgtest regression with Qt 6.11.2

[Adrian Bunk]

On Mon, Sep 28, 2026 at 06:59:17PM +0200, Manik Bhattacharjee wrote:
> This was difficult to debug, because the test that fails does the following:
> - generates a CamiTK extension (.cpp/.h...)
> - compiles it as a .so library
> - calls a tool (camitk-config) that loads the generated library.
> - A segfault happens when a method in the generated library is called.

I didn't notice the segfault when I reported the bug.

> This works without issue when compiling the package from scratch with Qt
> 6.11.2.
> But running the test with the package from Sid/Testing (compiled using Qt
> 6.10), loading the extension compiled by the test using Qt6.11.2 crashes
> with the segfault.
> I known that there should be binary compatibility between Qt 6.10 and 6.11,
> but it seems that in our case a call to operator QStringList << segfaults in
> that situation.

The backtrace of the segfault I just looked at is:

#0  0x00007ffff7cdf73a in QArrayDataPointer<char16_t>::QArrayDataPointer (this=0x6d018294456bcae8, other=<optimized out>)
    at /usr/include/x86_64-linux-gnu/qt6/QtCore/qarraydatapointer.h:78
#1  QString::QString (this=0x6d018294456bcae8, other=<optimized out>) at /usr/include/x86_64-linux-gnu/qt6/QtCore/qstring.h:228
#2  QtPrivate::QMovableArrayOps<QString>::emplace<QString> (this=0x7fffffffd320, i=0) at /usr/include/x86_64-linux-gnu/qt6/QtCore/qarraydataops.h:755
#3  0x00007fffc406d5ae in QString& QList<QString>::emplaceBack<QString>(QString&&) ()
    at /tmp/camitk-6.0.0/debian/tests/actionAndComponentUsingViewerExtension/build/lib/camitk-6.0/components/libtestcomponents.so.6.0.
#4  0x00007fffc406d3bb in QList<QString>::append(QString&&) ()
    at /tmp/camitk-6.0.0/debian/tests/actionAndComponentUsingViewerExtension/build/lib/camitk-6.0/components/libtestcomponents.so.6.0.
#5  0x00007fffc406d12b in QList<QString>::operator<<(QString&&) ()
    at /tmp/camitk-6.0.0/debian/tests/actionAndComponentUsingViewerExtension/build/lib/camitk-6.0/components/libtestcomponents.so.6.0.
#6  0x00007fffc406cd1a in TestComponents::getFileExtensions() const ()
    at /tmp/camitk-6.0.0/debian/tests/actionAndComponentUsingViewerExtension/build/lib/camitk-6.0/components/libtestcomponents.so.6.0.
#7  0x00007ffff7cf6e23 in camitk::ExtensionManager::registerNewComponentExtension (ce=<optimized out>, filename=...)
    at ./sdk/libraries/core/ExtensionManager.cpp:323
#8  0x00007ffff7cfac6d in camitk::ExtensionManager::loadExtension (type=type at entry=camitk::ExtensionManager::COMPONENT, fileName=...)
    at /usr/include/x86_64-linux-gnu/qt6/QtCore/qarraydata.h:60
#9  0x00007ffff7cfc1a8 in camitk::ExtensionManager::autoload (type=type at entry=camitk::ExtensionManager::COMPONENT)
    at /usr/include/x86_64-linux-gnu/qt6/QtCore/qarraydata.h:60
#10 0x00007ffff7cfe0f6 in camitk::ExtensionManager::autoload () at ./sdk/libraries/core/ExtensionManager.cpp:51
#11 0x00007ffff7d464e4 in camitk::Application::Application
    (this=this at entry=0x7fffffffe180, name=..., theArgc=@0x7fffffffe12c: 2, theArgv=theArgv at entry=0x7fffffffe398, autoloadExtensions=autoloadExtensions at entry=true, registerFileExtension=registerFileExtension at entry=false, useSplashScreen=false) at ./sdk/libraries/core/application/Application.cpp:144
#12 0x0000555555558000 in main (argc=<optimized out>, argv=0x7fffffffe398) at ./sdk/applications/config/main.cpp:119

The QtPrivate in #2 seems to explain the problem.

> Can you try to just rebuild the package with the latest Qt ?
> Is there something I should put in debian/control to trigger recompilation
> for Qt version changes ?

I've added the Debian Qt maintainers to Cc for that.

The problem seems to be that an extension gets built in the autopkgtest 
that does for some reason use something from QtPrivate:: - and this is 
an extension is for a package that does not depend on qt6-base-private-abi.

> Thanks,
> 
> Manik.

cu
Adrian

BTW: The Debian BTS does not Cc the submitter.