Jarred

If you don't bundle certificates, users will report that your builtin https client doesn't work in production (usually in docker)

It spawns ephemeral EC2/Azure instances, which is a lot cheaper than the GitHub actions runners we used before that.

We shard to a lot of machines for tests and I’d be worried about running out if we used dedicated servers.

BuildKite is fine but I wouldn’t be that surprised if we move off of BuildKite to a custom thing at some point. Months ago, we switched from CMake to a handrolled typescript build system and it made our builds faster and simpler.

CI has always been expensive for Bun including before the acquisition. We build for [macOS, Linux, FreeBSD, Android, Windows] x [ARM64, x64] and then run tests on multiple Linux distros with multiple shards, multiple macOS versions and Windows for each architecture.

We recently started cross-compiling all the builds on Linux arm64 and that made it a little faster (I wrote a CLI tool to download the correct macOS headers for cross-compilation). We also have a daily cron job that asks claude to make the slowest tests faster while adding more assertions.

Claude Code is a large codebase and uses tons of Node’s features either directly or indirectly through dependencies. fetch(), node:http, node:tls, node:os, node:net, node:fs, AbortSignal, node:child_process, node:tty, node:process, node:http2, etc.

Does it print a bun.report link and can you paste it? I will investigate.

Bun’s Rust rewrite shipped in Claude Code over a month ago and barely anyone noticed. Claude Code is widely used. The Rust rewrite is going well overall.

In the Bun v1.4 video, I promised a certain number of newly passing Node.js tests were added to force us to improve compatibility, and that number is not true yet. The release is delayed until it is true. The PRs to make it true are up but not merged yet. Most likely next Tuesday we’ll do the release of 1.4.

Grouped and arena allocations work really well in Zig. For awhile, we tried to use this pattern almost everywhere in Bun but it gets really tricky when there’s some GC-managed memory and you want to free things incrementally to reduce RSS. Also, using arenas for arrays that grow wastes memory a lot since it keeps every previous version around (mimalloc arenas are slightly better for this)

Grouped allocations works especially well in parsers & ASTs where the lifetime is very bounded. Since the Rust rewrite, we still use arenas for Bun’s parsers and the bundler but not a ton elsewhere.

> new codebase doesn’t have any

Claude Code & Prisma use it as of last week.

Dynamic workflows, in my experience, make Claude more effective at complex long-running tasks. They help precisely with getting Claude to do the task correctly.

It feels more like a bespoke build system for the specific task/project than prompting a freeform chat.

> the Rust, Anthropic-focused rewrite

Nope. That's 100% me.

`PathString` worked the exact same way in our Zig code, with less visibility from the compiler & type system. And yes, it will be refactored heavily (or deleted overall) in the next week or so.

almost