Add support for first party inline scripts in thirdPartyErrorFilterIntegration

[patrikholcak]

We tried using drop-error-if-exclusively-contains-third-party-frames option but it appears to be ignoring inline scripts, which we’re using on our website.

You can verify this setting up sentry as follows

<script>
Sentry.init({
  integrations: [
    thirdPartyErrorFilterIntegration({
      filterKeys: ['mykey'],
      behaviour: 'apply-tag-if-exclusively-contains-third-party-frames',
    }),
  ],
  beforeSend(event) {
    console.log(event.tags) // { third_party_code: true }
    return null
  }
})
</script>

<script>throw new Error("First party script")</script>

Errors thrown in inline scripts will have third_party_code: true set. Setting behaviour: 'drop-error-if-exclusively-contains-third-party-frames' completely ignores any errors thrown in inline scripts.

What I’d like to propose is adding a data attribute on the inline script, which would identify it as first party:

<script data-sentry-key="mykey">throw new Error("First party script")</script>

You can actually grab a reference to the running script element with document.currentScript, so it should be doable and would help us not to flood Sentry with unrelated events.