Bug 30549

The http://trac.webkit.org/changeset/49782 commit has reveal a bug in QGWV's setCursor method. * Problem (manual backtrace): _1) Widget[Qt]::setCursor _2) QWebPageClient::setCursor _3) QGraphicsWebViewPrivate::updateCursor _4) QGraphicsItem::setCursor. _5) QGraphicsWidget::itemChange method is called as the first action of qgraphicsitem.cpp::setCursor (see qt/src/gui/graphicsview/qgraphicsitem.cpp). _6) QGraphicsWidget::itemChange fires QApplication::sendEvent(CursorChange), that is captured by QGWV's ::event. At this point QGWV cursor has not been set yet (remember we are in the middle of _3_ yet). _7) the quote below is executed: void QGraphicsWebView::event() { (...) if (event->type() == QEvent::CursorChange) { if (cursor().shape() == Qt::ArrowCursor) d->resetCursor(); } (...) } _8) d->resetCursor goes to 3) again, in an infinite loop ....... crash ! Solution: When QGraphicsItem::setCursor calls QGraphicsWidget::itemChange as its first action, it passes 'CursorChange' as 'change'. However we can not emit 'CursoChange' event yet (see loop above). At the end of setCursor method (when cursor had already been set), QGraphicsWidget::itemChange method is called again, but now passing the 'CursorHasChanged' as 'change'. This is the time we have to act in QGraphicsWebView. patch coming ...