Increase default max-cltv value

[t-bast]

LND and CLN already use 2016 blocks. The network is generally raising the values of cltv_expiry_delta to account for high on-chain fees, so we'll need to allow longer maximum deltas to avoid rejecting payments.

[codecov-commenter]

Codecov Report

Merging #2677 (9a3bb87) into master (e7b4631) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

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@@            Coverage Diff             @@
##           master    #2677      +/-   ##
==========================================
- Coverage   85.88%   85.87%   -0.01%     
==========================================
  Files         214      214              
  Lines       17591    17590       -1     
  Branches      728      734       +6     
==========================================
- Hits        15108    15106       -2     
- Misses       2483     2484       +1     

Impacted Files	Coverage Δ
...re/src/main/scala/fr/acinq/eclair/NodeParams.scala	93.64% <100.00%> (+0.02%)	⬆️
...in/scala/fr/acinq/eclair/channel/Commitments.scala	96.75% <100.00%> (ø)
...c/main/scala/fr/acinq/eclair/channel/Helpers.scala	95.03% <100.00%> (ø)
...in/scala/fr/acinq/eclair/channel/fsm/Channel.scala	86.05% <100.00%> (+0.22%)	⬆️
...cala/fr/acinq/eclair/router/RouteCalculation.scala	95.83% <100.00%> (ø)

... and 4 files with indirect coverage changes

[pm47]

I don't think that can work without also updating the value below as well:

eclair/eclair-core/src/main/scala/fr/acinq/eclair/channel/fsm/Channel.scala

Line 130 in e7b4631

val MAX_CLTV_EXPIRY_DELTA: CltvExpiryDelta = CltvExpiryDelta(7 * 144) // one week

[thomash-acinq]

It's a problem that we have so many constants defined in so many different places. Should MAX_CLTV_EXPIRY_DELTA be read from nodeParams instead of being a constant hidden in the code? And is DEFAULT_ROUTE_MAX_CLTV really needed?

[t-bast]

Good points, I cleaned up the constants in Channel.scala.

I'm not sure what to do with DEFAULT_ROUTE_MAX_CLTV in the Router: if we want to re-use the channel's maxExpiryDelta we need to provide the ChannelConf to path-finding which is weird...

[pm47]

The change LGTM, but I need to look at it a 2nd time after the week-end to be sure...

And is DEFAULT_ROUTE_MAX_CLTV really needed?

I think yes, in the context of trampoline.