[tor-bugs] #16559 [Torflow]: bwauth code needs to be smarter about failed circuits

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#16559: bwauth code needs to be smarter about failed circuits
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 Reporter:  TvdW     |          Owner:  aagbsn
     Type:  defect   |         Status:  new
 Priority:  major    |      Milestone:
Component:  Torflow  |        Version:
 Keywords:           |  Actual Points:
Parent ID:           |         Points:
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 In the current bandwidth authority code, when a fetch attempt fails, it
 will still be counted as a circuit that went through all of the nodes --
 even if those nodes weren't responsible for the failure.

 This has the potential of resulting in a relay not being measured
 sufficiently, or at all: the code will consider failures from unstable
 nodes to be relevant for nodes that are perfectly stable.

 In slices where exits and entries aren't well-distributed (like, all of
 them) this can result in some nodes not being measured at all, and losing
 their consensus weight. This seems to affect exits a lot more than it does
 other relay types: people on tor-relays@ have mentioned that removing
 their exit policies gets their consensus weight back, and I have been able
 to reproduce this.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/16559>
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