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by solid_fuel 20 days ago
Ehh, I think this take needs a grain of salt.

There's a few significant facts here:

- They had an existing functional Zig implementation

- They had an existing test suite for the Zip implementation

- They had a separate JavaScript compliance test suite with ~ 1 million tests

- The person overseeing the rewrite was responsible for a huge portion of the existing codebase and was very familiar with the existing architecture and problems

I don't think that middle management at most companies is going to be starting from that same point when it comes to building or updating something. Generally, I don't think there are many projects out there that have such robust existing tests and specifications.

In this case, the engineering behind the tests and specifications need to also be considered part of the process, since without those you wouldn't be able to build a control loop in the same way.

Also I'm pretty sure Walmart directly hires software engineers and doesn't just outsource everything - https://careers.walmart.com/us/en/results?searchQuery=softwa...

2 comments

Every single SaaS app will be completely rewritten in the next couple years. Fair warning. If you aren't on that train you won't have a job.
You are missing the big picture here The AI literally was able to do a year's work of a top notch developer team in just 11 days (mainly because of a lot of human intervention, otherwise it would have been faster) Why do you think its cant or wont be able to replace the lead developer and/or designer's 11 day job !

and btw, if it can write code, it can write tests and test suite

Ai has come a long way, 2 years ago, this task would be impossible ! 1 year ago, it would hit a dead-end in the first hours of the execution

This blog post is nothing short of an amazing and fascinating tale, yet in some aspect very very scary ...

No I'm not missing anything. The existing specifications and tests provide a huge validation surface to work against for this kind of migration - they're the foundational pieces of the control loop. Without those two things, this kind of rewrite would not be possible.

We have known for decades that the hard part in programming isn't programming, it's making sure you have the right target! Bad designs and bad specifications have caused more bugs and broken software than anything else, and the time taken to develop the testing and validation suites (that is - the javascript spec tests) this rewrite used must be considered part of the engineering effort.

> and btw, if it can write code, it can write tests and test suite

You must be very early in your career. Again, the hard part is not writing the test, it's knowing which tests to write.

> You are missing the big picture here The AI literally was able to do a year's work of a top notch developer team in just 11 days (mainly because of a lot of human intervention, otherwise it would have been faster) Why do you think its cant or wont be able to replace the lead developer and/or designer's 11 day job !

It would help if you actually engaged at all with any of the points they just made. They were good points!

I am also very curious what the actual cost of this is, esp. if you are not an Anthropic employee and have to pay the API cost.