QCAD Pro 3.32.9 random crashes on macOS 26 Tahoe - Qt 6.11.1 regression QTBUG-147602 (cursor / QImage::toCGImage)

QCAD Professional QCAD Troubleshooting and Problems
1

QCAD Version: 3.32.9 Professional (official package)

Downloaded package (file name): qcad-3.32.9-pro-macos-12.7-26-qt6-arm64.dmg (bundled Qt 6.11.1)

Operating System: macOS 26.5.2 (Tahoe), Mac mini M4, dual 6K displays (6016x3384 + 5760x3240)

Not drawing-specific - it happens with any drawing open.

I proceed like this:

QCAD quits unexpectedly at random moments while working, often when the mouse passes over a toolbar. The macOS crash report shows an EXC_BREAKPOINT (SIGTRAP) on the main thread while Qt converts a mouse cursor image:

QToolBar::event
    -> QWidget::setCursor
    -> QWindowPrivate::setCursor
    -> libqcocoa
    -> QImage::toCGImage()
    -> CGImageCreate
    -> verify_image_parameters
    -> valid_image_colorspace
    -> CGColorSpaceGetType
    -> CFGetTypeID -> __CF_IS_OBJC   (invalid/stale CGColorSpaceRef)

This matches Qt upstream bug QTBUG-147602 line by line (Jira): a Qt 6.11.0/6.11.1 regression where qt_mac_cgImageFormatForImage() returns a raw CGColorSpaceRef whose owner goes out of scope before CGImageCreate() uses it (use-after-free). It was not present in Qt 6.10.2 and is marked Fixed for Qt 6.11.2 / 6.12 Beta2.

As a workaround I enabled “Use system cursors” (GraphicsView/SystemCursors=true), which avoids most QImage::toCGImage calls, but the Qt::SizeAllCursor set by QToolBar drag handles still seems to go through the same path, so occasional crashes may remain.

Would it be possible to rebuild the macOS packages with Qt >= 6.11.2 once it is released (or fall back to Qt 6.10.x / 6.8 LTS in the meantime)?

I can provide the full .ips crash report if useful.

Thanks for the great software!
Pietro

2

Many thanks for your detailed report. Yes, we will have to revert to 6.10 for macOS for the time being. We will likely issue a re-release of QCAD 3.32.9 for macOS with Qt 6.10 shortly (before the next scheduled update). I’ll keep you posted.

3

The QCAD 3.32.9 re-release with Qt 6.10 is now available from your download area. Please let us know if you still experience problems.