Originally I (incorrectly?) assumed that since TX_COMMITMENT_SIGNED
always came before TX_SIGNATURES, we would always receive a response
from openchannel_update (w/ commitment_secured = true) before getting
notification of receipt of the peer's signatures.
But it's observable in the logs of hung tests that this in fact is a
wrong assumption -- the notification for the tx_sigs arrives at our
spender plugin before the callback from our openchannel_update RPC.
This mis-ordering causes a hang.
Luckily we're pretty much setup to handle this race already w/ states
etc, minus actually calling the method advance the plot in case we're
ready.
2022-07-26T05:37:59.4529095Z lightningd-1 2022-07-26T05:10:07.395Z DEBUG 035d2b1192dfba134e10e540875d366ebc8bc353d5aa766b80c090b39c3a5d885d-dualopend-chan#2: peer_in WIRE_COMMITMENT_SIGNED
2022-07-26T05:37:59.4530452Z lightningd-1 2022-07-26T05:10:07.396Z DEBUG 035d2b1192dfba134e10e540875d366ebc8bc353d5aa766b80c090b39c3a5d885d-hsmd: Got WIRE_HSMD_VALIDATE_COMMITMENT_TX
2022-07-26T05:37:59.4530719Z lightningd-1 2022-07-26T05:10:07.396Z DEBUG hsmd: Client: Received message 35 from client
2022-07-26T05:37:59.4531386Z lightningd-1 2022-07-26T05:10:07.396Z DEBUG 035d2b1192dfba134e10e540875d366ebc8bc353d5aa766b80c090b39c3a5d885d-dualopend-chan#2: billboard: channel open: commitment received, sending to lightningd to save
2022-07-26T05:37:59.4531856Z lightningd-1 2022-07-26T05:10:07.398Z DEBUG 035d2b1192dfba134e10e540875d366ebc8bc353d5aa766b80c090b39c3a5d885d-dualopend-chan#2: peer_in WIRE_TX_SIGNATURES
>>> 2022-07-26T05:37:59.4532553Z lightningd-1 2022-07-26T05:10:07.400Z DEBUG plugin-spenderp: mfc 60:`openchannel_peer_sigs` notice received for channel 9d145e763f08ee6f715ba7677f869cbb9580c7406f4d0b0ff3a0987efe501e13 <<<< THIS ONE WAS ASSUMED TO COME AFTER openchannel_update (next line)
2022-07-26T05:37:59.4533048Z lightningd-1 2022-07-26T05:10:07.400Z DEBUG plugin-spenderp: mfc 60, dest 0: openchannel_update 035d2b1192dfba134e10e540875d366ebc8bc353d5aa766b80c090b39c3a5d885d returned.
2022-07-26T05:37:59.4554292Z lightningd-1 2022-07-26T05:10:07.400Z DEBUG plugin-spenderp: mfc 60: parallel `openchannel_update`.
2022-07-26T05:37:59.4555485Z lightningd-1 2022-07-26T05:10:07.400Z DEBUG plugin-spenderp: mfc 60: funding tx 50425e20dbf0ca6fe112a8811b8048edb5bfa8d2922079668c5f353b859b45cb
2022-07-26T05:37:59.4557934Z lightningd-1 2022-07-26T05:10:07.508Z DEBUG 0266e4598d1d3c415f572a8488830b60f7e744ed9235eb0b1ba93283b315c03518-hsmd: Got WIRE_HSMD_CUPDATE_SIG_REQ
2022-07-26T05:37:59.4558244Z lightningd-1 2022-07-26T05:10:07.508Z DEBUG hsmd: Client: Received message 3 from client
2022-07-26T05:37:59.4558738Z lightningd-3 2022-07-26T05:11:03.234Z DEBUG 0266e4598d1d3c415f572a8488830b60f7e744ed9235eb0b1ba93283b315c03518-gossipd: seeker: startup peer finished
2022-07-26T05:37:59.4559209Z lightningd-3 2022-07-26T05:11:03.234Z DEBUG 0266e4598d1d3c415f572a8488830b60f7e744ed9235eb0b1ba93283b315c03518-gossipd: seeker: state = PROBING_SCIDS Seeking scids 1 - 105
(The last 2 log messages (from a different node) are >1min after the last
log line from lightning-1, because lightning-1 hung)
Hacked lightningd up to test this (such that notification always sent
before the RPC response, works as intended w/ patch)
79a76a96f7