TypeError: partialRoute.split is not a function

[Michsior14]

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 package are you using?

@sentry/tracing

SDK Version

7.8.0

Framework Version

express 4.18.1, node 16.15.0

Link to Sentry event

No response

Steps to Reproduce

1. Update @sentry/tracing to 7.8.0.
2. Start the app
3. Wait for incoming request

Expected Result

Requests to the server are processes properly without any errors.

Actual Result

Each request fails with the following error (probably related to #5450):

TypeError: partialRoute.split is not a function
    at Function.process_params (./main.js:2:1855298)
    at next (./main.js:2:2554914)
    at Function.handle (./main.js:2:2553813)
    at router (./main.js:2:2552432)
    at ./main.js:2:1853557
    at Layer.handle [as handle_request] (./main.js:2:2560503)
    at trim_prefix (./main.js:2:2555773)
    at ./main.js:2:2555055
    at Function.process_params (./main.js:2:2555954)
    at Function.process_params (./main.js:2:1856043)

[Lms24]

Hi @Michsior14 and thanks for reporting. That looks like a bug introduced in #5450. Apologies for that.
The error message you get makes me think that the partialRoute variable is not a string. It can't be undefined either (because we fall back to '' as a default directly above) so it must be something else.

In your reproduction steps, you said that starting the app is enough. Can you confirm that? Or does it crash at an incoming request? Thanks for your help!

[Michsior14]

@Lms24 Ups, sorry! I've updated the description, obviously it crashes on the request.

[Lms24]

Thanks for clarifying @Michsior14! I poked a bit at the express source code but couldn't yet find out how the layer.path or layer.route.path variables could be something other than undefined or string.

To help us debug this, could you tell us about your Express app? I'd be interested in your Sentry config as well as in a route that fails. Doesn't have to be the whole app but enough to reproduce this. Thanks!

[Michsior14]

@Lms24 I found out what causes the issue. According to express docs it's allowed to define the paths as regex and one of my apps is using them a lot for different purposes. The code bellow with the latest SDK is a problem:

router.get(/\/file/, (_: express.Request, res: express.Response, next: express.NextFunction) => {
  next();
});

[Lms24]

Awesome, thanks @Michsior14! That makes sense. Now that we know how to reproduce it, we'll try to fix this asap.