SPLICE LOCKED Race Condition

Legend:
Item -> means sent
Item <- means received
Chan X (implies a channel at block height X)
(Since these happen at different times)

Splice locked race condition example


Node A.               Node B.
* Channel starts at block height 100 
splice_locked      ->
                   <- splice_locked
                   <- commitments_signed (Chan 100)
                   -> splice_locked
                      Node B now considers splice locked (Chan 106)
                   <- commitments_signed (Chan 106)
splice_locked      <-
Node A now considers splice locked (Chan 106)
commitments_signed <- (Chan 100)
commitments_signed <- (Chan 106)

Node A considers the commitments_signed for Chan 100 invalid.
The commitments_signed for Chan 106 is, however, valid.

This example uses commitments_signed but remains a problem for any message
that depends on channel state.

Order of events:

0. A sends splice_locked
1. B sends splice_locked back at the same moment (also 6 block depth)
2. B sends commitment_signed for pre-splice tx (chan 100)
3. B rcv splice_locked from A (sent at 0)
4. B sends commitment_signed for splice tx (chan 106)

what should A do when it gets chan 100 commitment_signed??