---
title: Bun v1.0.9
description: "Fixes a glibc symbol version error, illegal instruction error, a Bun.spawn bug, an edgecase with peer dependency installs, and a JSX transpiler bugfix"
date: "2023-11-05T10:13:16.002Z"
author: jarred
draft: false
---

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`](/blog/bun-v1.0) - First stable release!
- [`v1.0.1`](/blog/bun-v1.0.1) - Named imports for .json and .toml files, fixes to `bun install`, `node:path`, and `Buffer`
- [`v1.0.2`](/blog/bun-v1.0.2) - Make `--watch` faster and lots of bug fixes
- [`v1.0.3`](/blog/bun-v1.0.3) - `emitDecoratorMetadata` and Nest.js support, fixes for private registries and more
- [`v1.0.4`](/blog/bun-v1.0.4) - `server.requestIP`, virtual modules in runtime plugins, and more
- [`v1.0.5`](/blog/bun-v1.0.5) - Fixed memory leak with `fetch()`, `KeyObject` support in `node:crypto` module, `expect().toEqualIgnoringWhitespace` in `bun:test`, and more
- [`v1.0.6`](/blog/bun-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`](/blog/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`](/blog/bun-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:

{% codetabs %}

```sh#curl
$ curl -fsSL https://bun.sh/install | bash
```

```sh#npm
$ npm install -g bun
```

```sh#brew
$ brew tap oven-sh/bun
$ brew install bun
```

```sh#docker
$ docker pull oven/bun
$ docker run --rm --init --ulimit memlock=-1:-1 oven/bun
```

{% /codetabs %}

To upgrade Bun:

```sh
$ 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.

```ts
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:

```jsx
<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](https://github.com/dylan-conway) for fixing this bug!