5 ms·

I feel like we need to heavily differentiate between a rewrite and an AI rewrite.

mrklol 2mo ago
I agree but I think from Bun we learned that a project with really good tests and enough tokens can be converted from one language to another quite good!
colordrops 2mo ago
Is there any measurable difference in quality between the two, or are you just going on "vibes"? Is there a correlation between the quality of the manually written code and AI generated code driven by the same dev? Such crude takes only cause unnecessary friction. If you have a black box that spits out code, and you are unable to distinguish the quality between a top tier dev and an AI inside the black box, then the distinction is unnecessary. Most of the code on the internet is already a black box to you. What percentage of code running on your machines have you vetted by who wrote it and code quality? AI coding isn't going anywhere and will likely end up generating most code going forward so instead of rejecting it outright or arbitrarily categorizing it we need to focus on solid quantitative and qualitative measures of code and functionality regardless of who wrote it.
- queoahfh 2mo ago
  Didn't the initial rewrite of Bun into Rust have an ocean of "unsafe" in it, and wasn't it entirely dysfunctional?
  - Leynos 2mo ago
    Yes, that was the point. It made unsafe behaviour visible in a way that could be addressed. I hadn't heard any reports of it being dysfunctional.
    - iigijshaba 2mo ago
      I have read up on it again, and while it was entirely dysfunctional at the very early stages, it quickly came up to par or beyond, with the LLM especially helped by the huge test suite written in Typescript, different from both Zig and Rust. However, Jarred still describes a lot of unsafe, and usage of Miri in continuous integration. Funnily enough, RAII is cited as a major benefit of rewriting from Zig to Rust, while C++ already has RAII. I wonder if C++ and Rust are more suited to larger programs than Zig, unless the architecture in Zig is handled carefully.
      - andy_ppp 2mo ago
        The LLMs may have seen larger codebases in Rust, helping them to cope better.
  - kzrdude 2mo ago
    There's still no release of rust-bun so then it might just not exist (until it proves itself).
    - pohl 2mo ago
      Yesterday we learned that it’s been shipping with Claude Code since mid June, so it has a lot of active users already. Also, the unsafe footprint seems reasonable — the bulk of it in FFI wrappers.
- dwedge 2mo ago
  > Is there a correlation between the quality of the manually written code and AI generated code driven by the same dev? If the dev doesn't vet the code, it doesn't matter how good quality a dev they would be if they wrote the code - they didn't. Sure, the dev would probably drive the initial architecture discussion better and some people are using AI in small batches with tests and vetting everything, but some previously great devs are throwing in PRs that touch hundreds of files at once with one commit. A lot of people I previously considered great developers have become people I would not recommend for a job in the past 2-3 years. > If you have a black box that spits out code, and you are unable to distinguish the quality between a top tier dev and an AI inside the black box, then the distinction is unnecessary. Sure, but this is just begging the question. If nobody could tell, the term 'slop' wouldn't have become so popular.
  - colordrops 2mo ago
    You must be replying to a different comment. Seems completely unrelated to what I wrote. I never claimed that there wasn't AI slop. My point is that there are different levels of code coming out of AI, both due to the quality of the model and harness, and the quality of the engineer that is driving it. Thus you can't just bucket all AI developed code the same. 100% there is slop created by humans and really solid code bases generated by AI driven by a meticulous developer. You are making the exact error I was addressing, which is bucketing all AI code as the same.
    - dwedge 2mo ago
      I quote-replied to your comment, so I doubt it was unrelated. > I never claimed that there wasn't AI slop No, but you implied that a top tier dev doesn't produce slop when using AI. > If you have a black box that spits out code, and you are unable to distinguish the quality between a top tier dev and an AI inside the black box My point was that "if" is doing a lot of heavy lifting here and you're coming very close to begging the question. > bucketing all AI code as the same. Most people are not "top tier devs" and over time this will probably become more true. Even if I accepted your premise that "top tier devs" only generate solid code bases with AI, the ease of entry and the ease of spitting out thousands of lines of code means the ratio of bad AI to good AI will not go in a good direction unless it becomes too expensive for non "top tier devs" to use. Given this, I think it's fair to assume AI code is low quality until proven otherwise.
- lenkite 2mo ago
  > Is there a correlation between the quality of the manually written code and AI generated code driven by the same dev? Aren't you making a strawman argument ? AFAIK this project is not made by an official PostgreSQL core developer, so the entire premise of your argument is invalid.
  - colordrops 2mo ago
    I phrased that improperly which made you and probably others misunderstand. What I meant is, is the quality of AI generated code correlated with the developer? The answer is yes, a bad dev will absolutely produce worse code using AI than a good developer - the point being that there isn't just one level of quality of code coming out of AI, even with the same model and harness.
mebcitto 2mo ago
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”?
- Dormeno 2mo ago
  When the majority of the code is written by AI, it is more than 50%.
- guenthert 2mo ago
  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?
- lowsong 2mo ago
  > I think close to 100% of new ambitious projects are going to leverage AI at least to some degree. Once the free money dries up that number will rapidly tend towards 0%. > So how much AI usage does it make it an “AI rewrite”? Any amount.
baq 2mo ago
It’s just a build step now.
satvikpendem 2mo ago
It is more and more the future. No human would want to rewrite one technology to another because it is too marginal a gain. AI on the other hand does not give a shit.
- Zecc 2mo ago
  You underestimate what people are willing to do just for fun.
  - dawnerd 2mo ago
    Yeah like what do they think the people porting doom to everything possible are thinking?
- queenkjuul 2mo ago
  > No human would want to rewrite one technology to another Except for when they do, like the new TypeScript...
  - satvikpendem 2mo ago
    That was before good end to end models though, they started it in 2024 where it was in 2025 that models were capable of long term continuous work.
bozdemir 2mo ago
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.
- raincole 2mo ago
  Or, you know, you can use Postgres. It's right there for you.
  - bozdemir 2mo ago
    why? if a rewrite is better/faster/secure, why not? (I'm not saying PGrust is better, I didnt even install it, my perspective is in general)
    - mahogany 2mo ago
      Of course, if the rewrite is all of those things, then it seems like a good option. The whole point is how do we know if it actually is better.
    - uecker 2mo ago
      Because it is not trustworthy, which is really the most important thing.
- OtomotO 2mo ago
  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 :)
  - piker 2mo ago
    Which you will necessarily have if they’ve completed a Rust rewrite.
  - bigupthewhole 2mo ago
    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.
jatins 2mo ago
rewrites feel like an area where LLMs are better suited than humans imo It’s mostly grunt work and LLMs are well suited for translation tasks (iirc transformers arch was originally invented for translation)
silon42 2mo ago
It's not that... It's a rewrite by project maintainers vs a fork.
maxloh 2mo ago
For instance, the TypeScript rewrite in Go was done mostly by humans and took a year before it was released. That is how you rewrite software that people can trust.
- rjh29 2mo ago
  AI is a great use for this kind of boring, rote translation where precision is important. Humans are quite bad at it and tend to make mistakes. In either case the focus should be on improving testing, not trying to manually verify if the translation was correct by eye.
  - IsTom 2mo ago
    With programs large enough tests aren't going to ever be enough. Formal verification might work, but then who checks the specification for bugs?
    - copperx 2mo ago
      In the case of rewrites, the specification is the original behavior, no? bugs and all.
      - hoppp 2mo ago
        There is often no spec, just the old code, copied with the old bugs and with new ones sprinkled on top.
      - IsTom 2mo ago
        Deciding if two programs do the same thing is provably impossible in the strict mathematical sense.
    - cyphar 2mo ago
      I really wonder where all of these people who believe that tests perfectly encapsulate the behaviour of software come from. Maybe it's because LLMs happen to work better when you give them acceptance criteria and people struggle to distinguish between "better" and "good"?
egorfine 2mo ago
We already have a well established term for AI rewrites.
byzantinegene 2mo ago
A human rewrite without maintenance is just a hobby project. An AI rewrite is just wasting tokens for god knows what?
langs 2mo ago
nope. any rewrite will be an AI rewrite soon.

I agree but I think from Bun we learned that a project with really good tests and enough tokens can be converted from one language to another quite good!

colordrops 2mo ago

Is there any measurable difference in quality between the two, or are you just going on "vibes"? Is there a correlation between the quality of the manually written code and AI generated code driven by the same dev? Such crude takes only cause unnecessary friction. If you have a black box that spits out code, and you are unable to distinguish the quality between a top tier dev and an AI inside the black box, then the distinction is unnecessary. Most of the code on the internet is already a black box to you. What percentage of code running on your machines have you vetted by who wrote it and code quality? AI coding isn't going anywhere and will likely end up generating most code going forward so instead of rejecting it outright or arbitrarily categorizing it we need to focus on solid quantitative and qualitative measures of code and functionality regardless of who wrote it.

queoahfh 2mo ago
Didn't the initial rewrite of Bun into Rust have an ocean of "unsafe" in it, and wasn't it entirely dysfunctional?
- Leynos 2mo ago
  Yes, that was the point. It made unsafe behaviour visible in a way that could be addressed. I hadn't heard any reports of it being dysfunctional.
  - iigijshaba 2mo ago
    I have read up on it again, and while it was entirely dysfunctional at the very early stages, it quickly came up to par or beyond, with the LLM especially helped by the huge test suite written in Typescript, different from both Zig and Rust. However, Jarred still describes a lot of unsafe, and usage of Miri in continuous integration. Funnily enough, RAII is cited as a major benefit of rewriting from Zig to Rust, while C++ already has RAII. I wonder if C++ and Rust are more suited to larger programs than Zig, unless the architecture in Zig is handled carefully.
    - andy_ppp 2mo ago
      The LLMs may have seen larger codebases in Rust, helping them to cope better.
- kzrdude 2mo ago
  There's still no release of rust-bun so then it might just not exist (until it proves itself).
  - pohl 2mo ago
    Yesterday we learned that it’s been shipping with Claude Code since mid June, so it has a lot of active users already. Also, the unsafe footprint seems reasonable — the bulk of it in FFI wrappers.
dwedge 2mo ago
> Is there a correlation between the quality of the manually written code and AI generated code driven by the same dev? If the dev doesn't vet the code, it doesn't matter how good quality a dev they would be if they wrote the code - they didn't. Sure, the dev would probably drive the initial architecture discussion better and some people are using AI in small batches with tests and vetting everything, but some previously great devs are throwing in PRs that touch hundreds of files at once with one commit. A lot of people I previously considered great developers have become people I would not recommend for a job in the past 2-3 years. > If you have a black box that spits out code, and you are unable to distinguish the quality between a top tier dev and an AI inside the black box, then the distinction is unnecessary. Sure, but this is just begging the question. If nobody could tell, the term 'slop' wouldn't have become so popular.
- colordrops 2mo ago
  You must be replying to a different comment. Seems completely unrelated to what I wrote. I never claimed that there wasn't AI slop. My point is that there are different levels of code coming out of AI, both due to the quality of the model and harness, and the quality of the engineer that is driving it. Thus you can't just bucket all AI developed code the same. 100% there is slop created by humans and really solid code bases generated by AI driven by a meticulous developer. You are making the exact error I was addressing, which is bucketing all AI code as the same.
  - dwedge 2mo ago
    I quote-replied to your comment, so I doubt it was unrelated. > I never claimed that there wasn't AI slop No, but you implied that a top tier dev doesn't produce slop when using AI. > If you have a black box that spits out code, and you are unable to distinguish the quality between a top tier dev and an AI inside the black box My point was that "if" is doing a lot of heavy lifting here and you're coming very close to begging the question. > bucketing all AI code as the same. Most people are not "top tier devs" and over time this will probably become more true. Even if I accepted your premise that "top tier devs" only generate solid code bases with AI, the ease of entry and the ease of spitting out thousands of lines of code means the ratio of bad AI to good AI will not go in a good direction unless it becomes too expensive for non "top tier devs" to use. Given this, I think it's fair to assume AI code is low quality until proven otherwise.
lenkite 2mo ago
> Is there a correlation between the quality of the manually written code and AI generated code driven by the same dev? Aren't you making a strawman argument ? AFAIK this project is not made by an official PostgreSQL core developer, so the entire premise of your argument is invalid.
- colordrops 2mo ago
  I phrased that improperly which made you and probably others misunderstand. What I meant is, is the quality of AI generated code correlated with the developer? The answer is yes, a bad dev will absolutely produce worse code using AI than a good developer - the point being that there isn't just one level of quality of code coming out of AI, even with the same model and harness.

mebcitto 2mo ago

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”?

Dormeno 2mo ago
When the majority of the code is written by AI, it is more than 50%.
guenthert 2mo ago
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?
lowsong 2mo ago
> I think close to 100% of new ambitious projects are going to leverage AI at least to some degree. Once the free money dries up that number will rapidly tend towards 0%. > So how much AI usage does it make it an “AI rewrite”? Any amount.

baq 2mo ago

It’s just a build step now.

satvikpendem 2mo ago

It is more and more the future. No human would want to rewrite one technology to another because it is too marginal a gain. AI on the other hand does not give a shit.

Zecc 2mo ago
You underestimate what people are willing to do just for fun.
- dawnerd 2mo ago
  Yeah like what do they think the people porting doom to everything possible are thinking?
queenkjuul 2mo ago
> No human would want to rewrite one technology to another Except for when they do, like the new TypeScript...
- satvikpendem 2mo ago
  That was before good end to end models though, they started it in 2024 where it was in 2025 that models were capable of long term continuous work.

bozdemir 2mo ago

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.

raincole 2mo ago
Or, you know, you can use Postgres. It's right there for you.
- bozdemir 2mo ago
  why? if a rewrite is better/faster/secure, why not? (I'm not saying PGrust is better, I didnt even install it, my perspective is in general)
  - mahogany 2mo ago
    Of course, if the rewrite is all of those things, then it seems like a good option. The whole point is how do we know if it actually is better.
  - uecker 2mo ago
    Because it is not trustworthy, which is really the most important thing.
OtomotO 2mo ago
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 :)
- piker 2mo ago
  Which you will necessarily have if they’ve completed a Rust rewrite.
- bigupthewhole 2mo ago
  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.

jatins 2mo ago

rewrites feel like an area where LLMs are better suited than humans imo It’s mostly grunt work and LLMs are well suited for translation tasks (iirc transformers arch was originally invented for translation)

silon42 2mo ago

It's not that... It's a rewrite by project maintainers vs a fork.

maxloh 2mo ago

For instance, the TypeScript rewrite in Go was done mostly by humans and took a year before it was released. That is how you rewrite software that people can trust.

rjh29 2mo ago
AI is a great use for this kind of boring, rote translation where precision is important. Humans are quite bad at it and tend to make mistakes. In either case the focus should be on improving testing, not trying to manually verify if the translation was correct by eye.
- IsTom 2mo ago
  With programs large enough tests aren't going to ever be enough. Formal verification might work, but then who checks the specification for bugs?
  - copperx 2mo ago
    In the case of rewrites, the specification is the original behavior, no? bugs and all.
    - hoppp 2mo ago
      There is often no spec, just the old code, copied with the old bugs and with new ones sprinkled on top.
    - IsTom 2mo ago
      Deciding if two programs do the same thing is provably impossible in the strict mathematical sense.
  - cyphar 2mo ago
    I really wonder where all of these people who believe that tests perfectly encapsulate the behaviour of software come from. Maybe it's because LLMs happen to work better when you give them acceptance criteria and people struggle to distinguish between "better" and "good"?

egorfine 2mo ago

We already have a well established term for AI rewrites.

byzantinegene 2mo ago

A human rewrite without maintenance is just a hobby project. An AI rewrite is just wasting tokens for god knows what?

langs 2mo ago

nope. any rewrite will be an AI rewrite soon.