Sourcemaps not working for Vercel + Sveltekit (paths for stack trace frames are absolute from the root filesystem rather than relative)

[fnimick]

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/sveltekit

SDK Version

7.92.0

Framework Version

Sveltekit 2.0.6

Link to Sentry event

https://million-marker.sentry.io/issues/4829645193/

SDK Setup

  Sentry.init({
    dsn: "https://7f6570917828021f8dea53dc2b778775@o1098001.ingest.sentry.io/4505744165699584",
    tracesSampleRate: 1,
    environment: PUBLIC_DEPLOY_ENV,
  });

Steps to Reproduce

At some point (not clear when), errors are being captured with the absolute path of the running file in the stack track frame (e.g. /var/task/vercel/path0/.svelte-kit/output/server/entries/endpoints/sentry-example/_server.js) rather than the expected relative stack track frame. This means that the sourcemaps are not matching, since the source map path being searched for is ~/var/task/vercel/path0/.svelte-kit/output/server/entries/endpoints/sentry-example/_server.js and the actual source map path from my uploaded artifact is ~/entries/endpoints/sentry-example/_server.js.

Expected Result

The stack trace should contain a relative frame which corresponds to generated source maps.

Actual Result

The stack trace frame is the full path, from the root /, of the running file in the Vercel VM.

[Lms24]

Hi @fnimick thanks for writing in! Can you show me your sentrySvelteKit config in you vite.config.js file?

Based on #8256, our Vite plugin should read the output directory during build and hand it to the server side SDK of Sentry. The SDK will rewrite the stack frame filenames, removing the absolute path before the output directory.

[fnimick]

@Lms24

    sentrySvelteKit({
      adapter: "vercel",
      autoUploadSourceMaps: process.env.PUBLIC_SENTRY_DISABLED !== "true",
      sourceMapsUploadOptions: {
        org: "million-marker",
        project: "future",
      },
      autoInstrument: false,
    }),
    sveltekit(), .....etc

This config hasn't changed since our first integration (which had no source map issues), so I doubt it's the source of the problem?

[Lms24]

I have a couple of concrete questions to debug this (alternatively, please feel free to provide a minimal reproducible example as a GH repo so we can debug it ourselves):

1. Can you set debug: true in sentrySvelteKit options and verify that there are no errors or warnings logged?
2. Can you confirm that there are logs from [Source Maps Plugin] during build?
3. Did you rename hooks.server.ts or move it to a location other than src/hooks.server.ts?
4. To verify that we correctly inject the discovered output directory into the server side code, please log the value of globalThis.__sentry_sveltekit_output_dir on the server side. I suggest logging it in beforeSend which should show us pretty well if the value is present at the time it's needed:

Sentry.init({
  dsn: 'DSN',
  // rest of your options
  beforeSend(event) {
    console.log(globalThis.__sentry_sveltekit_output_dir);
    return event;
  }
});

I have a feeling that this global value might not be set correctly but we need to verify this first.