Bun instrumentation stops working if reload is called on the server

[nathankleyn]

Is there an existing issue for this?

• I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• I have reviewed the documentation https://docs.sentry.io/
• I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

How do you use Sentry?

Sentry Saas (sentry.io)

Which SDK are you using?

@sentry/bun

SDK Version

8.51.0

Framework Version

Bun 1.1.45

Link to Sentry event

No response

Reproduction Example/SDK Setup

Sentry.init({
  tracesSampleRate: 1.0,
  environment: "some_env",
});

// server before reloading is instrumented
const server = Bun.serve({
  async fetch(_req) {
    throw new Error("I should have instrumentation, and I do");
  },
  port: 3000,
});

// server after reloading is not instrumented
server.reload({
  async fetch(_req) {
    throw new Error("I should have instrumentation, but I don't");
  },
})

await fetch('http://localhost:3000/');

Steps to Reproduce

1. Create a Bun server
2. Reload the server
3. Throw an error in the handler and look at the Sentry error

Reloading is done out of the box by some frameworks built on top of Bun Serve, like ElysiaJS (which does it after AOT / precompilation is completed).

Expected Result

The error should have instrumentation, such as request URL, request headers, browser information and trace information:

Actual Result

The error has no instrumentation at all:

[Lms24]

Hey @nathankleyn thanks for reporting this! I see you're already working on a fix for this? I had a quick look at the commit and it looks good to me. Are you interested in opening a PR once it's ready?

[nathankleyn]

Hey @Lms24 — thanks so much for your superfast reply! I've raised the PR now at #15148 (review), although I hit a bit of a problem when I discovered the tests for the @sentry/bun basically all were not actually working in practice (silently nothing was being tested due to how the tests were structured).

I've reworked the tests a bit and raised a working version but I will definitely need a small amount of assistance to solve one last remaining problem with test isolation before it can be merged.

Thanks in advance!