Details
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Bug
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Resolution: Done
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P1: Critical
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6.1.2, 6.2.0 Beta1, 6.2.0 Beta2
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None
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macOS 11.5, MacBook Air 2020 (intel), Qt6 6.1.2/6.2b1/6.2b2
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macOS
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06235d36ae9d00366215e748d80ff0faed3c2124 (qt/qtbase/dev) 2366be3c2c1e0277f5dba178729fa38a2d1d8dbe (qt/qtbase/6.2)
Description
If a QWidget containing a QVBox- or QHBoxLayout is added to a QGraphicsScene that is large enough to cause the parent QGraphicsView to allow for scrolling any such scroll motion will cause a crash in what looks like a recursive wheelEvent handler.
This crash is currently 100% reproducible on macOS 11.x in all available Qt6 versions.
The problem does however not occur on Windows 10 nor on any platform with Qt5.
I attached a simple code example that reproduces the issue reliably.
Steps to reproduce:
- extract the sample project attached to this bug
- run qmake6 to create a Makefile
- run make to build the project
- run 'open wheelCrash.app' to open the generated app
- attempt to scroll the view
Expected behaviour:
- the view should scroll without issue, revealing it's hidden items
Observed behaviour:
- the application crashes 100% of the time
Here is the gist of the backtrace, which is always identical.
I will attache the full trace to the issue:
0 tiny_malloc_should_clear + 228 1 szone_malloc_should_clear + 66 2 _malloc_zone_malloc + 118 3 QArrayData::allocate(QArrayData**, long long, long long, long long, QArrayData::AllocationOption) + 222 4 QList<QPainterPath::Element>::reserve(long long) + 129 5 QPainterPath::addRect(QRectF const&) + 444 6 non-virtual thunk to QGraphicsWidget::shape() const + 65 7 QGraphicsItem::collidesWithPath(QPainterPath const&, Qt::ItemSelectionMode) const + 436 8 QGraphicsSceneIndexPrivate::itemCollidesWithPath(QGraphicsItem const*, QPainterPath const&, Qt::ItemSelectionMode) + 30 9 QtPrivate::intersect_rect(QGraphicsItem const*, QRectF const&, Qt::ItemSelectionMode, QTransform const&, void const*) + 764 10 QGraphicsSceneIndexPrivate::recursive_items_helper(QGraphicsItem*, QRectF, bool (*)(QGraphicsItem const*, QRectF const&, Qt::ItemSelectionMode, QTransform const&, void const*), QList<QGraphicsItem*>*, QTransform const&, Qt::ItemSelectionMode, double, void const*) const + 497 11 QGraphicsSceneIndexPrivate::items_helper(QRectF const&, bool (*)(QGraphicsItem const*, QRectF const&, Qt::ItemSelectionMode, QTransform const&, void const*), QList<QGraphicsItem*>*, QTransform const&, Qt::ItemSelectionMode, Qt::SortOrder, void const*) const + 151 12 QGraphicsSceneIndex::items(QRectF const&, Qt::ItemSelectionMode, Qt::SortOrder, QTransform const&) const + 234 13 QGraphicsScenePrivate::itemsAtPosition(QPoint const&, QPointF const&, QWidget*) const + 412 [... this part of the trace repeats a few hundret times start ...] 14 QGraphicsScene::wheelEvent(QGraphicsSceneWheelEvent*) + 89 15 QGraphicsScene::event(QEvent*) + 1100 16 QApplicationPrivate::notify_helper(QObject*, QEvent*) + 247 17 QApplication::notify(QObject*, QEvent*) + 501 18 QCoreApplication::notifyInternal2(QObject*, QEvent*) + 169 19 QGraphicsView::wheelEvent(QWheelEvent*) + 460 20 QWidget::event(QEvent*) + 1226 21 QFrame::event(QEvent*) + 43 22 QGraphicsView::viewportEvent(QEvent*) + 1223 23 QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) + 232 24 QApplicationPrivate::notify_helper(QObject*, QEvent*) + 227 25 QApplication::notify(QObject*, QEvent*) + 7477 26 QCoreApplication::notifyInternal2(QObject*, QEvent*) + 169 [... this part of the trace repeats a few hundret times end ...] 499 QGraphicsView::wheelEvent(QWheelEvent*) + 460 500 QWidget::event(QEvent*) + 1226 501 QFrame::event(QEvent*) + 43 502 QGraphicsView::viewportEvent(QEvent*) + 1223 503 QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) + 232 504 QApplicationPrivate::notify_helper(QObject*, QEvent*) + 227 505 QApplication::notify(QObject*, QEvent*) + 7477 506 QCoreApplication::notifyInternal2(QObject*, QEvent*) + 169 507 QGraphicsProxyWidget::wheelEvent(QGraphicsSceneWheelEvent*) + 805 508 QGraphicsItem::sceneEvent(QEvent*) + 660 509 QGraphicsScene::wheelEvent(QGraphicsSceneWheelEvent*) + 514 510 QGraphicsScene::event(QEvent*) + 1100 511 QApplicationPrivate::notify_helper(QObject*, QEvent*) + 247