When replaying messages during channel-reestablishment,
previously we first resent all update messages, along with potential commitment_signed messages,
and then we potentially resent a single revoke_and_ack.
This can result in incorrect behaviour in case both a commitment_signed and a revoke_and_ack needs to be resent.
When replaying messages, the relative order of commitment_signed and revoke_and_messages needs to be preserved.
(the order of updates (htlc/fee) in relation to the revack messages does not matter)
implements https://github.com/lightning/bolts/pull/810
The logic here is somewhat based on what c-lightning does:
01e5f1886e/channeld/channeld.c (L3059)
This is most useful when receiving MPP where there is a non-trivial chance
that we have received some HTLCs for a payment but not all, and the user
closes the program. We try to fail them and wait for the fails to get
ACKed, with a timeout of course.
Move the balance calculation from lnchannel to lnhtlc.
Maintain a running balance in lnhtlc that is coupled with _maybe_active_htlc_ids
for practicality reasons.
1. In lnhtlc, sent_in_ctn and failed_in_ctn need to look at the
remote ctx, and they need to be called when we receive a revocation,
not when we send one.
2. In lnchannel, we use 3 lnworker callbacks:
- payment sent/payment failed (called when we receive a revocation)
- payment received (called when we send a revocation)
3. Make revoke_current_commitment return a single value.
The second value was only used in tests, there is no need
to bloat the code with that
In recv_rev() previously all unacked_local_updates were deleted
as it was assumed that all of them have been acked at that point by
the revoke_and_ack itself. However this is not necessarily the case:
see new test case.
renamed log['unacked_local_updates'] to log['unacked_local_updates2']
to avoid breaking existing wallet files
Replay un-acked local updates (including commitment_signed) byte-for-byte.
If we have sent them a commitment signature that they "lost" (due to disconnect),
we need to make sure we replay the same local updates, as otherwise they could
end up with two (or more) signed valid commitment transactions at the same ctn.
Multiple valid ctxs at the same ctn is a major headache for pre-signing spending txns,
e.g. for watchtowers, hence we must ensure these ctxs coincide.
