Express/Koa/Restify plugin adds new error callbacks on each request without removing old callbacks, resulting in the wrong request being reported and timeouts

[hansottowirtz]

Describe the bug

These lines are run on every request in the express plugin:

bugsnag-js/packages/plugin-express/src/express.js

Lines 22 to 32 in 8d607ca

	const requestClient = client._config.autoTrackSessions ? client.resumeSession() : clone(client)
	// attach it to the request
	req.bugsnag = requestClient
	// extract request info and pass it to the relevant bugsnag properties
	requestClient.addOnError((event) => {
	const { metadata, request } = getRequestAndMetadataFromReq(req)
	event.request = { ...event.request, ...request }
	requestClient.addMetadata('request', metadata)
	}, true)

When autoTrackSessions: true (which is the default), the same requestClient is used as for previous requests. This means that a new callback is added to the error callbacks array on every request. This has the following consequences:

• The wrong request is reported in the Request tab on Bugsnag (the body of the first request is always used, regardless of the request that caused the error)
• After many requests, the Bugsnag flush times out (we think this is the reason)

Is it possible that old callbacks are not removed when they should be?

Steps to reproduce

I think any express/koa/restify app without autoTrackSessions: false will have this problem.

Environment

We're using the Express plugin together with the AWS Lambda plugin.

• Bugsnag version: 7.17.0

[luke-belton]

Hi @hansottowirtz - the fix in #1887 for the issue you addressed in this PR has been released in https://github.com/bugsnag/bugsnag-js/releases/tag/v7.19.0. 🎉 Thanks for reporting this!