Bun

Bun v1.0.9

Jarred Sumner · November 5, 2023

Bun v1.0.9 fixes regressions impacting usage in Vercel & older CPUs, a Bun.spawn bug, an edgecase with peer dependency installs, and a JSX transpiler bugfix.

Bun is an incredibly fast JavaScript runtime, bundler, transpiler, and package manager — all in one. In case you missed it, here are some of the recent changes to Bun:

  • v1.0.0 - First stable release!
  • v1.0.1 - Named imports for .json and .toml files, fixes to bun install, node:path, and Buffer
  • v1.0.2 - Make --watch faster and lots of bug fixes
  • v1.0.3 - emitDecoratorMetadata and Nest.js support, fixes for private registries and more
  • v1.0.4 - server.requestIP, virtual modules in runtime plugins, and more
  • v1.0.5 - Fixed memory leak with fetch(), KeyObject support in node:crypto module, expect().toEqualIgnoringWhitespace in bun:test, and more
  • v1.0.6 - Fixes 3 bugs (addressing 85 👍 reactions), implements overrides & resolutions in package.json, and fixes regression impacting Docker usage with Bun
  • v1.0.7 - Fixes 59 bugs (addressing 78 👍 reactions), implements optional peer dependencies in bun install, and makes improvements to Node.js compatibility.
  • v1.0.8 - Fixes 138 bugs (addressing 257 👍 reactions), makes require() use 30% less memory, adds module mocking to bun test, fixes more bun install bugs

To install Bun:

curl
npm
brew
docker
curl
curl -fsSL https://bun.sh/install | bash
npm
npm install -g bun
brew
brew tap oven-sh/bun
brew install bun
docker
docker pull oven/bun
docker run --rm --init --ulimit memlock=-1:-1 oven/bun

To upgrade Bun:

bun upgrade

"Illegal instruction" and glibc symbol version regression from v1.0.8 is fixed

In Bun v1.0.8, we moved our internal build-system from a bespoke 2,000 line Makefile to CMake & Ninja. This was to simplify our build system for contributors and to make it easier to build Bun on Windows.

Along the way, there were three regressions:

  1. Bun v1.0.8 would crash with an "Illegal instruction" error on older CPUs (e.g. Intel Xeon E5-2670 v1) and some Linux arm64 CPUs. This impacted Docker users and users of older CPUs.
  2. Bun v1.0.8 would crash with a "symbol not found" error for those using < glibc 2.28. This impacted Vercel users and users of older Linux distributions.
  3. bun init would incorrectly print the version number in the README.md

These regressions are fixed, but they are embarassing for a post 1.0 product and I am sorry.

Here's what we're doing to prevent this from happening again:

  1. We are adding a CI job that runs on a machine with an older CPU to test Bun on older CPUs
  2. We are adding a CI job to check the minimum required version of glibc used by Bun's final executable and throw an error if it requests a version that is too new
  3. We added a test to ensure bun init prints the correct version number in the README.md

Bun.spawn bugfixes

This release fixes two bugs in Bun.spawn. We've also added more tests to Bun.spawn.

Fixed: await spawn(...).exited sometimes returned a string

await child.exited sometimes returned a string instead of a number. The string was the signal that caused the process to exit.

import { spawn } from "bun";

const child = spawn(["sleep", "1"]);
child.kill();
const code = await child.exited;

// Before:
console.log(code); // "SIGHUP"

// After:
console.log(code); // 129

Instead of returning a string, await child.exited now returns a number. This is consistent with what our TypeScript types declared, what our documentation said, and what bash's exit codes do.

If the process exited normally, it returns 0. If the process exited due to a signal, it returns 128 + signal number. For example, if the process exited due to SIGTERM, it would return 128 + 15 = 143.

Fixed: edgecase causing await spawn(...).exited to not resolve

An edgecase that could cause await spawn(...).exited to not resolve has been fixed.

bun install peer dependency too many versions bugfix

In this release, we began porting some tests from other package managers to Bun.

One of the tests uncovered an issue where Bun would not re-use a peer dependency's version from the existing project. This is fixed to align with the behavior of npm.

We've also added a warning when a peer dependency's chosen version is incompatible with the version range specified in the package.json.

JSX transpiler bugfix

Either of the following lines of code would previously cause a runtime panic due to an assertion failure:

<A key={() => {}} b={class {}} />
<A key={() => {}} b={() => {}} />

This is fixed.

The bug was due to special handling of the key prop causing the AST nodes to not be visited in the order they were parsed. This bug could occur if the key prop created a scope, such as defining a function or class.

Thanks to @dylan-conway for fixing this bug!