Comment by jakelazaroff
14 days ago
Unfortunately, a hard constraint of (state-based) CRDTs is that merging causally concurrent changes must be commutative. ie it is possible that clients will not be able to agree on the order of CRDT operations, and they must be able to arrive at the same state after applying them in any order.
I don't think that's required, unless you definitionally believe otherwise.
When clients disagree about the the order of events and a conflict results then clients can be required to roll back (apply the inverse of each change) to the last point in time where all clients were in agreement about the world state. Then, all clients re-apply all changes in the new now-agreed-upon order. Now all changes have been applied and there is agreement about the world state and the process starts anew.
This way multiple clients can work offline for extended periods of time and then reconcile with other clients.
Eg-walker seems similar to what you're proposing [0]. A more in-depth video by the creator [1].
[0] https://loro.dev/docs/advanced/event_graph_walker
[1] https://www.youtube.com/watch?v=rjbEG7COj7o
That's not how the CRDT concept works.
You're free to argue that this isn't "pure" CRDT, but the CRDT algorithm still runs normally, just a bit later than it otherwise would.