Crash on announce receive handler

[faragher]

One of my NomadNet programs crashes every few days to few weeks. I just caught the log:

[2023-08-09 14:17:37] [Extra] Valid announce for <a6ff59611bb0f4674db719e94885e7ae> 2 hops away, received via <445853aca89b5d92d02dd2f727896a35> on LocalInterface[37428]
[2023-08-09 14:17:37] [Debug] Destination <a6ff59611bb0f4674db719e94885e7ae> is now 2 hops away via <445853aca89b5d92d02dd2f727896a35> on LocalInterface[37428]
[2023-08-09 14:17:37] [Error] An unhandled exception occurred, the details of which will be dumped below
[2023-08-09 14:17:37] [Error] Error while processing external announce callback.
[2023-08-09 14:17:37] [Error] Type  : <class 'AttributeError'>
[2023-08-09 14:17:37] [Error] The contained exception was:
[2023-08-09 14:17:37] [Error] Value : 'ListEntry' object has no attribute '_cache_translation'
[2023-08-09 14:17:38] [Error] Trace :
  File "/home/faragher/.local/bin/nomadnet", line 8, in <module>
    sys.exit(main())
  File "/home/faragher/.local/lib/python3.10/site-packages/nomadnet/nomadnet.py", line 51, in main
    program_setup(configarg, rnsconfigarg, daemon, console)
  File "/home/faragher/.local/lib/python3.10/site-packages/nomadnet/nomadnet.py", line 11, in program_setup
    app = nomadnet.NomadNetworkApp(
  File "/home/faragher/.local/lib/python3.10/site-packages/nomadnet/NomadNetworkApp.py", line 362, in __init__
    nomadnet.ui.spawn(self.uimode)
  File "/home/faragher/.local/lib/python3.10/site-packages/nomadnet/ui/__init__.py", line 29, in spawn
    return TextUI()
  File "/home/faragher/.local/lib/python3.10/site-packages/nomadnet/ui/TextUI.py", line 207, in __init__
    self.loop.run()
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/main_loop.py", line 287, in run
    self._run()
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/main_loop.py", line 385, in _run
    self.event_loop.run()
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/main_loop.py", line 790, in run
    self._loop()
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/main_loop.py", line 818, in _loop
    self._entering_idle()
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/main_loop.py", line 779, in _entering_idle
    callback()
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/main_loop.py", line 574, in entering_idle
    self.draw_screen()
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/main_loop.py", line 588, in draw_screen
    canvas = self._topmost_widget.render(self.screen_size, focus=True)
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/widget.py", line 145, in cached_render
    canv = fn(self, size, focus=focus)
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/container.py", line 1089, in render
    body = self.body.render((maxcol, maxrow-ftrim-htrim),
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/widget.py", line 145, in cached_render
    canv = fn(self, size, focus=focus)
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/container.py", line 2130, in render
    canv = w.render(sub_size,
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/widget.py", line 145, in cached_render
    canv = fn(self, size, focus=focus)
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/widget.py", line 1761, in render
    canv = get_delegate(self).render(size, focus=focus)
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/widget.py", line 145, in cached_render
    canv = fn(self, size, focus=focus)
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/container.py", line 1565, in render
    canv = w.render((maxcol, rows), focus=focus and item_focus)
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/widget.py", line 145, in cached_render
    canv = fn(self, size, focus=focus)
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/container.py", line 2130, in render
    canv = w.render(sub_size,
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/widget.py", line 145, in cached_render
    canv = fn(self, size, focus=focus)
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/decoration.py", line 819, in render
    canv = self._original_widget.render((maxcol,maxrow-top-bottom),focus)
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/widget.py", line 145, in cached_render
    canv = fn(self, size, focus=focus)
  File "/home/faragher/.local/lib/python3.10/site-packages/nomadnet/vendor/additional_urwid_widgets/widgets/indicative_listbox.py", line 109, in render
    middle, top, bottom = self._listbox.calculate_visible(modified_size, focus=focus)
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/listbox.py", line 389, in calculate_visible
    n_rows = next.rows( (maxcol,) )
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/widget.py", line 205, in cached_rows
    return fn(self, size, focus)
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/widget.py", line 1019, in rows
    return len(self.get_line_translation(maxcol))
  File "/home/faragher/.local/lib/python3.10/site-packages/urwid/widget.py", line 1035, in get_line_translation
    return self._cache_translation

[2023-08-09 14:17:38] [Verbose] Saving directory...
[2023-08-09 14:17:38] [Verbose] Nomad Network Client exiting now
[2023-08-09 14:17:38] [Debug] Saved 26 peers to storage

It appears it's attempting to call _cache_translation on a list, which may be an error handling problem in NomadNet or an implementation problem in urwid.

Instance is running over SSH and has not had its size changed since NN startup.

[markqvist]

Thanks for capturing and providing the log. These cache errors crop up from urwid every now and then, and are a bit of a pain to troubleshoot. For now, I'll wrap the announce handler to catch the exception when it occurs, since it should only affect one UI update cycle.