[tor-bugs] #5902 [Tor Client]: The whole "choose a doomed exit at random" business is busted

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#5902: The whole "choose a doomed exit at random" business is busted
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 Reporter:  nickm       |          Owner:                    
     Type:  defect      |         Status:  new               
 Priority:  normal      |      Milestone:  Tor: 0.2.3.x-final
Component:  Tor Client  |        Version:                    
 Keywords:              |         Parent:                    
   Points:              |   Actualpoints:                    
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 From discussion on #3296:

 If we ever hit the "doomed exit at random" message, *every* exit needs to
 have n_supported == -1. So if we seeing that one, not only is it hopeless
 to build a circuit to the chosen exit for your predicted port; it is also
 hopeless to try to build a circuit at all, I think.

 Arma says: "We're launching a new circuit, repeatedly, when we really
 ought to be telling the stream to fail. This whole 'doomed exit' thing was
 supposed to improve our robustness during edge cases. But I think it just
 leads to sadness."

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/5902>
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