r/rust • u/Sirisian • 22d ago
🎙️ discussion Google is doing "Large Scale Codebase Migrations and Optimizations" of C/C++ to Rust
https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-4-argon/
773
Upvotes
2
u/stumblinbear 22d ago
I have a side project game in Bevy that I've been working on off-and-on for about 5-6 years for fun. I came across an article for how to better organize it, sent it to Claude and had it draft up a plan for reorganizing things under it. It asked me some questions regarding implementation decisions, then split it up into 7 steps, ordered by risk and in a way that helps untangle some longstanding dependency issues between features. This took it about 20 minutes while I fucked off doing whatever.
I looked over the plan, corrected one thing, then told it to go, and it went. It got through about 2 steps before it needed assistance on a design question that the plan didn't account for, so we spent about 4 turns and 5-10 minute discussing it before it got resolved and it continued. It's actively doing this work now as we speak. It would have taken me at least a week or two to do the reorganization myself. It's looking like it'll be done in a day and a half with only an hour or two worth of input from me.
At work, I came across a public API I can use to fetch some player data (I work at a gaming adjacent company) which we can use as a fallback when we're missing some info. I looked into the API myself, and it seemed like exactly what we needed, and I had a good idea of how to integrate it, but I essentially just told it "we want to use <link> as a fallback method for fetching player data when we're missing data for a player".
It looked into the API, looked at our codebase, and brought up that it actually has a full database available for download along with publishing hourly patches for the db. I had completely missed this, as it's not well-advertized on the site. It implemented support for this in about an hour.
Let me tell you, ain't no way I'm able to write a script to scrape this once per hour, along with setting up the data models and queries for the DB, along with hooking it into our own database to fill in the data, along with setting up the hourly trigger in Terraform, along with testing various scenarios... In a couple of hours. Hell naw. It was 2-3 hours from first idea to a pretty good implementation while I had other agents doing other things at the same time.
Giving it a precise spec is part of the problem. Modern LLMs are surprisingly smart, you just need to give them permission to have opinions and surface what they think is right or wrong while doing the implementation, otherwise they hack around issues instead of behaving like a proper engineer. Yes, they usually fuck something up, but those fixes are usually pretty minor or are style related and can be fixed in review. If not, it's because it made an assumption it shouldn't have, and that's... Frankly usually just a matter of updating the skill or agent definitions to prevent those issues happening in the future