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

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#29500: Broken circuitpadding unittests on appveyor
-------------------------------------------------+-------------------------
 Reporter:  asn                                  |          Owner:  teor
     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:  3
  padding, 041-proposed, 040-must, tor-ci-fail-  |
  sometimes                                      |
Parent ID:  #28631                               |         Points:  3
 Reviewer:  nickm                                |        Sponsor:
                                                 |  Sponsor2
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Changes (by teor):

 * status:  needs_revision => new


Comment:

 Replying to [comment:33 mikeperry]:
 > I would request that we not merge hacky changes to the unittests for the
 #29990 workarounds.

 Ok, I'll close my pull requests on this ticket, and mark #29990 as
 040-backport.

 > If we're going to hack this, let's hack it so monotime_init() (or the
 ratchet) has a non-zero value, and then we can go through circpad for the
 rare cases where the difference between monotime_init() and the first
 ratchet update is 0 (or negative), in production (which I still believe
 should be rare/impossible).

 These situations are rare, but they can happen. And they can happen more
 than you think.

 *Any* pre-ratchet monotime update can be zero or negative, because the
 Windows API and gettimeofday() don't provide monotonic source times. So
 any number of calls to the monotonic time functions may return the same
 value.

 Would you like to open a new ticket to test and fix these zero delta
 issues in circuitpad?
 #29990 is now about another bug, and this ticket is full of comments.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/29500#comment:34>
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