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CRDT is the dragon slayer

It's the sword that we needed! But it doesn't take us all the way. There are semantic conflicts that are difficult for CRDTs to solve alone.

What are the semantic conflicts you mean here?

As far as I can tell, CRDTs are the correct solution for syncing state between parties.

Merge conflicts that must be resolved by the user (i.e. when there is no logical way to determine the priority of two offline changes) are still an application specific problem, even with CRDTs. You can build structures that allow storing conflict resolutions in CRDTs, but getting them right is still like half the problem to solve.

I have lack of imagination to think what kind of conflicts those would be, would you have examples?

In my experience there’s always a logical way to solve conflicts. And CRDTs can have any kind of conflict resolution algorithm, so it’s customizable per application. “Storing conflict resolutions”, eg. “a merge operation”, is not needed and unnecessarily complicates any CRDT.

Yes, sometimes it is hard to come up with the merge strategy that preserves user intent. I think the big one is rich text, where Peritext[0] looks like a good direction.

[0]: https://www.inkandswitch.com/peritext/

This is the correct answer :)

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