File poly (ie, not component poly — see Notes/POLY for components)
commit - one key in the tip cset, one elsewhere
check in resync - one key in remote and the other key in local
commit in the resync - commit + check in resync conditions
Complain about all duplicates of "rkey dkey" in the weave.
Non-error cases can be quieted by putting "dkey" in the etc/ignore-poly file
converge code - does (in essence) a sort -u as part of the converge. (really, a merge -s, for set based (hash) merge)
when reading from the RESYNC, read the resync dir first, then main repo Follow bk cat rules for reading file.