Add defenses against looping paths

[thomash-acinq]

No description provided.

[t-bast]

👍

[codecov-commenter]

Codecov Report

Merging #2109 (536f413) into master (8afb02a) will decrease coverage by 0.07%.
The diff coverage is 33.33%.

@@            Coverage Diff             @@
##           master    #2109      +/-   ##
==========================================
- Coverage   87.63%   87.56%   -0.08%     
==========================================
  Files         165      165              
  Lines       12778    12783       +5     
  Branches      559      561       +2     
==========================================
- Hits        11198    11193       -5     
- Misses       1580     1590      +10     

Impacted Files	Coverage Δ
...cala/fr/acinq/eclair/router/RouteCalculation.scala	97.14% <25.00%> (-2.13%)	⬇️
.../src/main/scala/fr/acinq/eclair/router/Graph.scala	97.70% <50.00%> (-0.56%)	⬇️
...scala/fr/acinq/eclair/crypto/WeakEntropyPool.scala	89.47% <0.00%> (-5.27%)	⬇️
...main/scala/fr/acinq/eclair/router/Validation.scala	90.76% <0.00%> (-1.54%)	⬇️
...cinq/eclair/payment/receive/MultiPartHandler.scala	93.18% <0.00%> (-1.52%)	⬇️
...clair/channel/publish/ReplaceableTxPublisher.scala	85.71% <0.00%> (-1.10%)	⬇️
...c/main/scala/fr/acinq/eclair/channel/Channel.scala	87.88% <0.00%> (+0.07%)	⬆️
...main/scala/fr/acinq/eclair/io/PeerConnection.scala	85.82% <0.00%> (+0.38%)	⬆️
...ala/fr/acinq/eclair/balance/ChannelsListener.scala	96.55% <0.00%> (+3.44%)	⬆️

[pm47]

Small detail (no unnecessary degree of liberty by instantiating a new exception, and more consistent with the next handler):

          case Failure(failure: InfiniteLoop) =>
            log.error(s"found infinite loop ${failure.loop.map(edge => edge.desc).mkString(" -> ")}")
            Metrics.FindRouteErrors.withTags(tags.withTag(Tags.Error, "InfiniteLoop")).increment()
            ctx.sender() ! Status.Failure(failure)