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Bug
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Resolution: Unresolved
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P1: Critical
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None
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6.8.3, 6.9.2, 6.10.0 Beta4
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None
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Linux/Wayland,
macOS,
Windows
Description:
If QWebEngineView is deleted while a document is being printed, the application crashes.
Steps to Reproduce:
- Open a large document (e.g. a big PDF).
- Click the "Print" button.
- Start printing using view->print(printer).
- Delete the QWebEngineView before the printFinished signal is emitted. (e.g. by closing the window in the attached example)
Expected Result:
- Printing should stop gracefully, possibly with an error message in the console.
Actual Result:
- The application crashes.
For example code with debug output:
Widget::~Widget()
{
qDebug() << "~QWidget()";
qDebug() << "printer state" << printer_->printerState();
printer_->abort(); // has no effect
}
void Widget::printRequested()
{
qDebug() << "create QPrinter";
printer_ = new QPrinter(QPrinter::HighResolution);
printer_->setOutputFormat(QPrinter::PdfFormat);
printer_->setOutputFileName("/tmp/printer_example.pdf");
connect(view_, &QWebEngineView::destroyed, this, [this]() {
qDebug() << "destroy QPrinter";
delete printer_;
}, Qt::SingleShotConnection);
connect(view_, &QWebEngineView::printFinished, this, [](bool ok) {
qDebug() << "print done with" << ok;
}, Qt::SingleShotConnection);
view_->print(printer_);
qDebug() << "start printing" << printer_->printerState();
}
Output:
create QPrinter start printing 0 ~QWidget() printer state 1 destroy QPrinter QPaintDevice: Cannot destroy paint device that is being painted .../webview_print_crash_test_001" terminated abnormally.
Full minimal example
