Using :download on about:blank segfaults

[The-Compiler]

Version info:

qutebrowser v3.1.0
Git commit: a9f6ad973 on main (2023-12-08 15:30:58 +0000)
Backend: QtWebEngine 6.6.1, based on Chromium 112.0.5615.213 (from api)
Qt: 6.6.1

Does the bug happen if you start with --temp-basedir?: yes

Description

19:28:25 DEBUG    commands   command:run:513 command called: download
19:28:25 DEBUG    commands   command:run:527 Calling qutebrowser.browser.commands.CommandDispatcher.download(<qutebrowser.browser.commands.CommandDispatcher>, None, mhtml_=False, dest=None)
19:28:25 DEBUG    downloads  qtnetworkdownloads:fetch:537 fetch: PyQt6.QtCore.QUrl('about:blank') -> about:blank.html
19:28:25 DEBUG    downloads  downloads:_on_begin_insert_row:1056 _on_begin_insert_row with idx 0, webengine False
19:28:25 DEBUG    prompt     prompt:ask_question:138 Asking question <qutebrowser.utils.usertypes.Question default='/tmp/qutebrowser-basedir-y6x1wv8e/download/' mode=<PromptMode.download: 5> option=None text='Please enter a location for <b>about:blank</b>' title='Save file to:'>, blocking False, loops [], queue deque([])
[New Thread 0x7ffec209e6c0 (LWP 34662)]
19:28:25 DEBUG    prompt     prompt:_on_show_prompts:323 Displaying prompt qutebrowser.mainwindow.prompt.DownloadFilenamePrompt(question=<qutebrowser.utils.usertypes.Question default='/tmp/qutebrowser-basedir-y6x1wv8e/download/' mode=<PromptMode.download: 5> option=None text='Please enter a location for <b>about:blank</b>' title='Save file to:'>)
19:28:25 DEBUG    modes      modeman:enter:360 Entering mode KeyMode.prompt (reason: question asked)
19:28:25 DEBUG    statusbar  bar:set_mode_active:336 Setting prompt flag to True
19:28:25 DEBUG    misc       app:on_focus_object_changed:570 Focus object changed: <qutebrowser.mainwindow.prompt.LineEdit, className='LineEdit'>
19:28:25 DEBUG    misc       mainwindow:_update_overlay_geometry:348 new geometry for <qutebrowser.mainwindow.prompt.PromptContainer win_id=0>: PyQt6.QtCore.QRect(10, 1619, 1885, 479)
19:28:25 DEBUG    modes      modeman:_handle_keypress:309 match: SequenceMatch.ExactMatch, forward_unbound_keys: auto, passthrough: False, is_non_alnum: False, dry_run: False --> filter: True (focused: <qutebrowser.mainwindow.prompt.LineEdit, className='LineEdit'>)
19:28:25 DEBUG    message    message:_log_stack:40 Stack for error message:
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/home/florian/proj/qutebrowser/git/qutebrowser/__main__.py", line 15, in <module>
    sys.exit(qutebrowser.qutebrowser.main())
  File "/home/florian/proj/qutebrowser/git/qutebrowser/qutebrowser.py", line 231, in main
    return app.run(args)
  File "/home/florian/proj/qutebrowser/git/qutebrowser/app.py", line 115, in run
    ret = qt_mainloop()
  File "/home/florian/proj/qutebrowser/git/qutebrowser/app.py", line 125, in qt_mainloop
    return objects.qapp.exec()
  File "/home/florian/proj/qutebrowser/git/qutebrowser/browser/qtnetworkdownloads.py", line 345, in _on_reply_error
    self._die(error)
  File "/home/florian/proj/qutebrowser/git/qutebrowser/browser/downloads.py", line 525, in _die
    self.error.emit(msg)
  File "/home/florian/proj/qutebrowser/git/qutebrowser/browser/downloads.py", line 967, in _on_error
    message.error("Download error: {}".format(msg))
  File "/home/florian/proj/qutebrowser/git/qutebrowser/utils/message.py", line 58, in error
    stack = ''.join(traceback.format_stack())
19:28:25 ERROR    message    message:error:63 Download error: Protocol "about" is unknown
19:28:25 DEBUG    misc       mainwindow:_update_overlay_geometry:348 new geometry for <qutebrowser.mainwindow.messageview.MessageView object at 0x7fffb8bc43a0>: PyQt6.QtCore.QRect(0, 2075, 1905, 23)
19:28:25 DEBUG    modes      modeman:leave:428 Leaving mode KeyMode.prompt (reason: aborted)
19:28:25 DEBUG    statusbar  bar:set_mode_active:336 Setting prompt flag to False
19:28:25 DEBUG    prompt     prompt:_on_mode_left:202 Left mode KeyMode.prompt, hiding <qutebrowser.utils.usertypes.Question default='/tmp/qutebrowser-basedir-y6x1wv8e/download/' mode=<PromptMode.download: 5> option=None text='Please enter a location for <b>about:blank</b>' title='Save file to:'>
19:28:25 DEBUG    prompt     prompt:_on_show_prompts:298 Deleting old prompt qutebrowser.mainwindow.prompt.DownloadFilenamePrompt(question=<qutebrowser.utils.usertypes.Question default='/tmp/qutebrowser-basedir-y6x1wv8e/download/' mode=<PromptMode.download: 5> option=None text='Please enter a location for <b>about:blank</b>' title='Save file to:'>)
19:28:25 DEBUG    prompt     prompt:_on_show_prompts:302 No prompts left, hiding prompt container.
19:28:25 DEBUG    modes      tabbedbrowser:on_release_focus:874 Focus released, focusing <qutebrowser.browser.webengine.webenginetab.WebEngineTab tab_id=0 url='about:blank'>
19:28:25 DEBUG    misc       app:on_focus_object_changed:570 Focus object changed: <PyQt6.QtWidgets.QWidget object at 0x7fffa0f67010, className='QQuickWidget'>
19:28:25 DEBUG    misc       app:on_focus_object_changed:570 Focus object changed: <PyQt6.QtCore.QObject object at 0x7fffa0f67010, className='QtWebEngineCore::RenderWidgetHostViewQtDelegateItem'>
19:28:25 DEBUG    modes      modeman:leave:421 Ignoring leave request for KeyMode.prompt (reason left in other window) as we're in mode KeyMode.normal
19:28:25 DEBUG    modes      modeman:leave:428 Leaving mode KeyMode.normal (reason: enter normal: restore mode before prompt)

Thread 1 "python3" received signal SIGSEGV, Segmentation fault.
0x00007ffff1993e46 in QFileInfoGatherer::getInfo(QFileInfo const&) const () from /usr/lib/libQt6Gui.so.6
(gdb) bt
#0  0x00007ffff1993e46 in QFileInfoGatherer::getInfo(QFileInfo const&) const () at /usr/lib/libQt6Gui.so.6
#1  0x00007ffff19a207c in QFileSystemModelPrivate::_q_fileSystemChanged(QString const&, QList<std::pair<QString, QFileInfo> > const&) () at /usr/lib/libQt6Gui.so.6
#2  0x00007ffff59a5447 in QObject::event(QEvent*) () at /usr/lib/libQt6Core.so.6
#3  0x00007ffff11a7dcc in sipQFileSystemModel::event(QEvent*) (this=0x55555654f360, a0=0x7ffeac00a9a0) at /usr/src/debug/pyqt6/PyQt6-6.6.1/build/QtGui/sipQtGuiQFileSystemModel.cpp:391
#4  0x00007ffff1f7319b in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/libQt6Widgets.so.6
[...]

How to reproduce

python3 -m qutebrowser --temp-basedir about:blank ":cmd-later 100 download"