[tor-bugs] #29500 [Core Tor/Tor]: Broken circuitpadding unittests on appveyor

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#29500: Broken circuitpadding unittests on appveyor
-------------------------------------------------+-------------------------
 Reporter:  asn                                  |          Owner:  (none)
     Type:  defect                               |         Status:  new
 Priority:  High                                 |      Milestone:  Tor:
                                                 |  0.4.0.x-final
Component:  Core Tor/Tor                         |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  wtf-pad, tor-relay, tor-cell,        |  Actual Points:
  padding, 041-proposed, 040-must                |
Parent ID:  #28631                               |         Points:
 Reviewer:                                       |        Sponsor:
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Comment (by teor):

 Replying to [comment:11 teor]:
 > Replying to [comment:10 mikeperry]:
 > > Replying to [comment:9 asn]:
 > > > Mike, wrt the `test_circuitpadding_tokens()` test, could it be
 another case where the test actually schedules legit padding because of a
 state transition or something and it might trigger or might not depending
 on how the timing of the test goes?  Like the one from #29122?
 > >
 > > Yes, that does seem likely for the tokens test. In fact, I think this
 should fix it, if we could reproduce:
 > > https://github.com/mikeperry-
 tor/tor/commit/b61cd3709be53dd0aee55111dc0c29b882c31cc6
 >
 > The 0.4.0 and master builds all failed due to this bug after #29599 was
 merged.
 >
 > But only the "Image: Visual Studio 2017; Environment:
 target=x86_64-w64-mingw32..." jobs failed, so it might be timing-
 sensitive. Or the OS bug might happen reliably on Windows Server 2016.
 >
 > You can remote desktop to the build machine if you want:
 > https://www.appveyor.com/docs/how-to/rdp-to-build-worker/
 >
 > It will be easier to set up if you use your own appveyor account, not
 Tor's.

 Or you could create your best fix for these issues, get it merged, and
 then see if it fails again?

 It might be easier that messing around with RDP: there's no guarantee
 you'd be able to reproduce the timing issues on Appveyor within the 1 hour
 job limit.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/29500#comment:12>
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