ctmnt

Man I miss Tracker.

I agree / hope that’s what they meant. It seems disingenuous, though, to describe it as unreadable, since obviously something has to read it to bake it into the deploy. And given their apparent lack of effective security boundaries in one area, why should we assume that they’ve got the deploy system adequately locked down?

It’s not like I had a ton of trust in them before, but now they’ve lost almost all credibility.

Where did you see that a Context employee had credentials stolen in February? I haven't run into that particular data point.

Not just into Vercel's env vars, but into Vercel's customer's env vars.

An email from Vercel came to my company at 10:47am UTC. It contained little information, and said:

> At this time, we do not have reason to believe that your Vercel credentials or personal data have been compromised.

Which is not very reassuring without actual information, since presumably they would have said the same thing on Saturday, if asked.

They mean the latter. Very unclear how that translates to meaningful security.

You’re right, I should have been more careful in my reference to AWS. No need to be snarky about it.

Let me rephrase: aside from that one example from a couple years ago, I haven’t seen any examples of production code written in Lean. I’d be very interested in being proven wrong, this isn’t something I desire, just what I’ve observed. Have you seen any others?

More generally, you implicitly make a good point: writing important libraries in Lean and calling in from another language is probably the most likely use case. So not programs / apps / binaries written in Lean, but small critical components.

You’re right, there is that one example. Feels like we’re in exception that proves the rule territory. But I’d be very interested in being proven wrong! This isn’t a desire of mine, just what I’ve seen. Do you have other examples?

Also, part of my confidence comes from both having been a professional programmer for decades, across many languages, and also having programmed in Lean. It’s a great language for math, perhaps the best choice right now. But as a general purpose language it’s incredibly quirky.

That is amazing. Compounded by the fact that there's a product listed as "COMING SOON JULY 2025"! This isn't an abandoned site.

Sure, but are you worried about someone cheating on their arXiv submission by exploiting a buffer overflow? It’s a real bug, it’s just not very important.

There are no Lean applications other than Lean. This is an important point most of the comments are missing. Lean is for proving math. Yes, you can use it for other things; but no, no one is.

Still good to have found, but drawing conclusions past “someone could cheat at proving the continuum hypothesis” isn’t really warranted.

Hi Kiran, thanks for following up. FWIW, I enjoy your blog and your work. And I do think it was a valuable bug you found; also nice to see how quickly Henrik fixed it.

Say more about people running Lean in production. I haven’t run into any. I know of examples of people using Lean to help verify other code (Cedar and Aeneas being the most prominent examples), but not the actual runtime being employed.

I took a quick scan of lean-lang.org just now, and, other than the two examples I mentioned, didn’t see a single reference to anything other than proving math.

I’m sure you’re in the Lean Zulup, based on what you’ve been up to. Are you seeing people talk about anything other than math? I’m not, but maybe I’m missing it.

Yes, it isn’t performant. Lean isn’t a language for writing software, though you technically can; it’s a language for proving math.

This looks cool enough, but it’s starting to drive me crazy how people are in such a rush to put out their macOS apps they can’t be bothered to get a developer account and run a one line command. It’s not hard.

I used to be sympathetic to complaints about not wanting to pay the developer account fee. But when you’re vibe coding, you’re probably paying a good chunk of change to your LLM supplier of choice every month, and the yearly developer account fee seems minor in comparison

Also, it’s just such a bad security precedent. This page describes the error you get as “the typical macOS Gatekeeper warning”, as though it were just another piece of corporate silliness, like clicking through a EULA.