I am not trolling, but I have a simple question: Why? Why do I use this instead of the official build? What is the business case?
I think a business case for a "look I let an LLM rewrite a large codebase" does not exist.
Postgres rewritten in Rust, now passing 100% of the Postgres regression tests
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Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests
#52Earlier quoted context omitted.
> not mostly the test, but the real world production scars Most extensive test suites are exactly production scars: every time you have a bug or a regression, you write a test that confirms correct behaviour. SQLite is a good example to bring up because its extensive closed-source tests are what’s often cited as being what keeps people from forking it. (Turso did it, though, but it takes a company to deliver some gua…
Sure, but behaviors that never have a bug or regression don't get a test. Software of this kind of complexity has all kinds of behavior that has never been broken, and doesn't have a specific test written for it. Getting an extensive test suite passing is certainly orders of magnitude better than having no test suite at all, but it still doesn't tell you as much as you need to know. I would absolutely never trust an…
> Software of this kind of complexity has all kinds of behavior that has never been broken
This space of things is astronomically larger than the space of things expressly covered by any test suite.
"Program testing can be used to show the presence of bugs, but never to show their absence." -Edsger W. Dijkstra
Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests
#53I start to see a lot of these re-writes that depend on tests to state that its working. But the things that make software like Postgres and SQLite reliable are not mostly the test, but the real world production scars. That's where the reliability comes from, years and years of running in production.
In a project like PostgreSQL, those scars are reflected in unit tests demonstrating that they’re fixed. It’d be hard to pass its test suite and not be as robust as the original.
Edsger W. Dijkstra:
"Program testing can be used to show the presence of bugs, but never to show their absence!"
Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests
#54I wonder how long this will be maintained for...
As long as tokens are cheap
Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests
#55Is this another llm-driven rewrite?
I wonder how many "unsafe" blocks are in there...
Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests
#56Earlier quoted context omitted.
I'd %100 prefer an opus 4.8 rewrite over %99 of the time. Unless Fabrice Bellard is rewriting the stuff I need, I'd prefer AI over a human coder.
AI is an average coder. It was trained on all code the code that could be found. Not just code written by genius programmers like Carmack and Bellard. Given that it's average, I'd prefer a human coder above average :)
Which you will necessarily have if they’ve completed a Rust rewrite.
Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests
#57Why should a developer use this for anything beyond a pet project? Just because it is written in Rust? All these "rewritten in rust" projects only reinforce the idea that a significant part of the rust community consists of software talibans and not of engineers who must deliver something that works and is reliable over time.
I think this shouldn't be taken too seriously, from what I understand it's an exploration of what's possible with today's LLMs. You're right to talk about the trend though, because what it shows is how the cost of re-writing well covered project has completely crashed, so that in itself is a learning.
The cost of surface level rewrites has crashed. Which will probably cover 80% of cases. Caveat emptor on which side your project falls.
Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests
#58Why so much negativity? I find these projects interesting for learning purposes and exploring new ways. What’s wrong with that?
Because it’s uncomfortable to see decades of work copied so trivially.
Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests
#59Earlier quoted context omitted.
I'd %100 prefer an opus 4.8 rewrite over %99 of the time. Unless Fabrice Bellard is rewriting the stuff I need, I'd prefer AI over a human coder.
AI is an average coder. It was trained on all code the code that could be found. Not just code written by genius programmers like Carmack and Bellard. Given that it's average, I'd prefer a human coder above average :)
You haven't been using AI extensively I presume...
I've been programming a long time and considered myself among the top in my domain and AI agents using like GPT 5.5 etc. are much better than me.
Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests
#60I feel like we need to heavily differentiate between a rewrite and an AI rewrite.
Not sure it’s so simple. I think close to 100% of new ambitious projects are going to leverage AI at least to some degree. I know a couple that have strict no-AI policies (e.g. Zig), but it’s a tiny minority i think. So how much AI usage does it make it an “AI rewrite”?
Dunno. I got rather the impression that it's ambitious single-developer projects with no intention of maintenance which leverage those 'AI' code generators the most.
Who wants to contribute to an unmaintainable code base?