Comment by FjordWarden
14 days ago
There was an article on this website not so long ago about using CRDTs for collaborative editing and there was this silly example to show how leaky this abstraction can be. What if your have the word "color" and one user replaces it with "colour" and another deletes the word, what does the CRDT do in this case? Well it merges this two edits into "u". This sort of makes me skeptical of using CRDTs for user facing applications.
There isn’t a monolithic “CRDT” in the way you’re describing. CRDTs are, broadly, a kind of data structure that allows clients to eventually agree on a final state without coordination. An integer `max` function is a simple example of a CRDT.
The behavior the article found is peculiar to the particular CRDT algorithms they looked at. But they’re probably right that it’s impossible for all conflicting edits to “just work” (in general, not just with CRDTs). That doesn’t mean CRDTs are pointless; you could imagine an algorithm that attempts to detect such semantic conflicts so the application can present some sort of resolution UI.
Here’s the article, if interested (it’s very good): https://www.moment.dev/blog/lies-i-was-told-pt-1
> There isn’t a monolithic “CRDT” in the way you’re describing.
I can't blame people for thinking otherwise, pretty much every self-called "CRDT library" I've come across implements exactly one such data structure, maybe parameterized.
It's like writing a "semiring library" and it's simply (min, +).