Manually sampling transactions result in missing child spans

[rhcarvalho]

• Review the documentation: https://docs.sentry.io/
• Search for existing issues: https://github.com/getsentry/sentry-javascript/issues
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• Provide a link to the affected event from your Sentry account: https://sentry.io/organizations/sentry-sdks/discover/sentry-javascript-browser:1fa6a688df6a472c95d574b6c93f1ed2/

Package + Version

• @sentry/browser
• @sentry/node
• raven-js
• raven-node (raven for node)
• other:

Version:

 6.1.0

Description

Originally reported at https://forum.sentry.io/t/child-spans-not-linked-to-parent/12854

Example to reproduce: https://codesandbox.io/s/wonderful-chaplygin-bwwjw?file=/src/App.js (thanks @dashed)

Given the code:

const tx = Sentry.startTransaction({ name: 'index', op: 'index', sampled: true });
const span = tx.startChild({ op: 'child' });
const span2 = span.startChild({ op: 'grandkid' });
span2.finish();
span.finish();
tx.finish();

None of the child spans are reported. Removing the sampled: true works as expected.