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Comment by imiric | Hacker News Reader

Hi there, and congrats on the launch. I've been following the project from the sidelines, as it has always seemed interesting.

Since everything in software engineering has tradeoffs, I have to ask: what are Unison's?

I've read about the potential benefits of its distributed approach, but surely there must be drawbacks that are worth considering. Does pulling these micro-dependencies or hashing every block of code introduce latency at runtime? Are there caching concerns w.r.t. staleness, invalidation, poisoning, etc.? I'm imagining different scenarios, and maybe these specific ones are not a concern, but I'd appreciate an honest answer about ones that are.

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Great question.

There are indeed tradeoffs; as an example, one thing that trips folks up in the "save typed values without encoders" world is that a stored value of a type won't update when your codebase's version of the type updates. On its face, that should be a self-evident concern (solvable with versioning your records); but you'd be surprised how easy it is to `Table.write personV1` and later update the type in place without thinking about your already written records. I mention this because sometimes the lack of friction around working with one part of Unison introduces confusion where it juts against different mental models.

Other general tradeoffs, of course, include a team's tolerance for newness and experimentation. Our workflow has stabilized over the years, but it is still off the beaten path, and I know that can take time to adjust to.

I hope others who've used Unison will chime in with their tradeoffs.

These seem to be mostly related to difficulties around adapting to a new programming model. Which is understandable, but do you have examples of more concrete tradeoffs?

For example, I don't think many would argue that for all the upsides a functional language with immutable state offers, performance can take a significant hit. And if can make certain classes of problems trickier, while simplifying others.

Surely with a model this unique, with the payoffs come costs.

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