Failure in decoding libtorrent DHT alert

[xoriole]

platform Darwin-18.7.0-x86_64-i386-64bit machine x86_64 python.version 3.7.4 (v3.7.4:e09359112e, Jul 8 2019, 14:54:52)

Traceback (most recent call last):
File "TriblerGUI/event_request_manager.py", line 114, in on_read_data
RuntimeError: [Failure instance: Traceback: <class 'RuntimeError'>: expected value (list, dict, int or string) in bencoded string
site-packages/twisted/internet/base.py:1283:run
site-packages/twisted/internet/base.py:1292:mainLoop
site-packages/twisted/internet/base.py:913:runUntilCurrent
site-packages/twisted/internet/task.py:239:__call__
--- <exception caught here> ---
site-packages/twisted/internet/defer.py:151:maybeDeferred
Tribler/Core/Libtorrent/LibtorrentMgr.py:578:_task_process_alerts
]

https://github.com/Tribler/tribler/blob/21fd6cae6866bf5c364479f2d83185e31fc8200c/Tribler/Core/Libtorrent/LibtorrentMgr.py#L577-L583

[ichorid]

Libtorrent versions >1.2.0 produce this error instead of None when encountering incorrect input, namely raw bytes and incorrect syntax. We use updated bindings on our machines, therefore we get this error. However, this could probably be because of alert.pkt_buf changed its type.

[ichorid]

Of course, we could just wrap the thing in a normal try-except block, but we still have to be sure that we can parse correct cases. Otherwise, by applying try-except we would introduce a piece of code that never does anything, and we can't check it.

@devos50 , you developed the BEP33 thing. Could you please fix it for Python 3.7 and ensure that the thing works after the fix (i.e. that BEP33 querying works)?

[ichorid]

@xoriole , we discussed this yesterday, could you please solve it by doing our own wrapper for bdecode that works the same (old) way in all versions of libtorrent?

[xoriole]

Fixed by https://github.com/Tribler/tribler/pull/4975