jschoubben
dfcdf234c5
A merge the gate handed is known by the bridge's word before the forge's, and finish wrote it already; an older forge-only merge heard in between overwrote it, since only the forge's word was dated and the write never compared with the head held. A merge is now dated by either word, and the write leaves a head that is a later merge, or one the gate cannot date while the merge is older than the records it keeps (a pruned newer merge).