Sentry SDK throws with dart compile js - cannot parse DSN (likely Flutter Web too)

[daniel-v]

Platform

Dart Web

Obfuscation

Disabled

Debug Info

Disabled

Doctor

dart info

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#### General info

- Dart 3.2.6 (stable) (Wed Jan 24 13:41:58 2024 +0000) on "linux_x64"
- on linux / Linux 6.7.5-200.fc39.x86_64 #1 SMP PREEMPT_DYNAMIC Sat Feb 17 17:20:08 UTC 2024
- locale is en_US.UTF-8

#### Project info

- sdk constraint: '>=2.17.0 <4.0.0'
- dependencies: sentry, web
- dev_dependencies: build_runner, build_web_compilers, lints

#### Process info

| Memory |  CPU | Elapsed time | Command line                                                                    |
| -----: | ---: | -----------: | ------------------------------------------------------------------------------- |
| 479 MB | 0.8% |        37:16 | dart language-server --protocol=lsp --client-id=VS-Code --client-version=3.82.0 |
| 487 MB | 2.9% |        06:51 | dart language-server --protocol=lsp --client-id=VS-Code --client-version=3.82.0 |

Version

7.16.1

Steps to Reproduce

Follow recommended sentry setup, provide a DSN to it that looks like:

https://aaaabbbb...@KKKKLLLLL.ingest.sentry.io/0000000

Make sure that dart2js is set to O0 (Oh, zero) optimization level (other options don't seem to affect the output).

I've done this via build.yaml

targets:
  $default:
    builders:
      build_web_compilers|dart_source_cleanup:
        release_options:
          enabled: false
      build_web_compilers:entrypoint:
        options:
          dart2js_args:
          - -O0
          # - --minify
          # - --fast-startup

Run the app with either webdev or build_runner.

dart run build_runner serve -r # or webdev serve -r

Expected Result

App to compile and run without errors.

❗ NOTE: other optimization levels, -O1, -O2, -O3 and -O4 all seem to generate proper output and there is NO error

Actual Result

The following exception is thrown:

js_helper.dart:1196 Uncaught TypeError: J.getInterceptor$asx(...).get$length is not a function
    at Object.get$length$asx (main.dart.js:669:45)
    at Object.Dsn_Dsn$parse (dsn.dart:54:31)
    at sentry.dart:253:9
    at _wrapJsFunctionForAsync_closure.$protected (async_patch.dart:307:19)
    at _wrapJsFunctionForAsync_closure.call$2 (async_patch.dart:332:23)
    at Object._asyncStartSync (async_patch.dart:237:3)
    at Object.Sentry__setDefaultConfiguration$body (sentry.dart:247:5)
    at Object.Sentry__setDefaultConfiguration (sentry.dart:247:5)
    at sentry.dart:123:15
    at _wrapJsFunctionForAsync_closure.$protected (async_patch.dart:307:19)

This is likely NOT a sentry issue but an SDK one. I do believe this also affects Flutter Web.

Minimum repro code

void main() {
  var uri = Uri.parse('https://aaaabbbb...@KKKKLLLLL.ingest.sentry.io/0000000');
  print('${uri.pathSegments.isEmpty}'); // dsn.dart:54 contains a similar expression
}

Run the above code with dart run build_runner serve web -r with -O0 in build.yaml.

The @ character is much disliked by -O0.

Are you willing to submit a PR?

Yes

[daniel-v]

This is likely relevant: dart-lang/sdk#55058

[buenaflor]

interesting edge case, thx for the deep dive! I'd assume this is blocked by the dart issue?

[daniel-v]

Correct. Someone one the Dart team said they would look at it.

What do you guys usually do in these situations? Update docs eg. or wait for fix?

[buenaflor]

In that case we would add it to our troubleshooting docs: https://docs.sentry.io/platforms/flutter/troubleshooting/

If you like you can also open up a PR for the site :) https://github.com/getsentry/sentry-docs/blob/master/docs/platforms/flutter/troubleshooting.mdx

it should be fine to document it there, we unfortunately don't have a dart troubleshooting page

[buenaflor]

Blocked by

• Uri.parse result with dart2js throws runtime error on -O0, while other levels are OK dart-lang/sdk#55058