fix(tracing): ignore the xhr/fetch response if its request is not being tracked

[datbth]

• If you've added code that should be tested, please add tests.
• Ensure your code lints and the test suite passes (yarn lint) & (yarn test).

A possible fix for #4427

[AbhiPrasad]

Thank you so much for the PR! This is def something we should have accounted for. Test is great as well.

Will merge after we've addressed the comment.

[AbhiPrasad]

we probably want this logic to be like:

if (handlerData.endTimestamp) {
  const spanId = handlerData.xhr.__sentry_xhr_span_id__;
  if (spanId) {
    const span = spans[spanId];
    if (span) {
      span.setHttpStatus(xhr.status_code);
      span.finish();

      // eslint-disable-next-line @typescript-eslint/no-dynamic-delete
      delete spans[spanId];
    }
  }
  return;
}

This is also more bundle size efficient

[datbth]

hi, thanks for looking into this.

I have refactored into using the spanId variable as suggested.
But I'm using eager-return style because it modifies less codes and I also believe multiple nesting levels is less readable. Not sure if it's significant to the bundle size?

[AbhiPrasad]

Well it's two return keywords rather than one (both of which can't be minified), but yeah the impact is probably minimal. We can leave it like this!

[AbhiPrasad]

This errors because we are now actually making the request, to a resource that doesn't exist.

As a quick thing to unblock we can just request http://example.com - but we should probably use SinonFakeServer like we do to test the xhr transport in

sentry-javascript/packages/browser/test/unit/transports/xhr.test.ts

Lines 18 to 24 in caba96e

	let server: SinonFakeServer;
	let transport: Transports.BaseTransport;
	describe('XHRTransport', () => {
	beforeEach(() => {
	server = fakeServer.create();
	server.respondImmediately = true;

[datbth]

oh somehow the tests did not fail on my machine. They do fail when I disable the Internet. I'm working on this

[datbth]

I could not get the tests to work properly with fake servers. But since these tests do not really care about the responses, I have fixed them by waiting for the requests to complete regardless of the result

[AbhiPrasad]

@datbth both your PRs were merged, they'll be out with the next release. Really appreciate the help!

If you're interested in continuing to help us out, we are hiring - and flexible to different locations! Email in GH profile if you want more details :)

[datbth]

Thanks, @AbhiPrasad. I'm happy to have worked with you guys.
For now I'll probably just be making these adhoc contributions. Thank you for the info!