ref(backend): Port functionality from Backend to Client

[Lms24]

This PR ports all the functionality from the Backend classes to the Client classes. This includes:

• Backend (interface)
• BaseBackend
• BrowserBackend
• NodeBackend
• TestBackend

Additionally, the PR fixes the unit tests in Core to spy on TestClient instead of TestBackend. Furthermore, all places where the Backend classes should be removed are marked with a TODO(v7) comment. The removal of the Backend classes will happen in a separate PR.

Ref:

• https://getsentry.atlassian.net/browse/WEB-803
• https://getsentry.atlassian.net/browse/WEB-773

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	20.11 KB (-0.17% 🔽)
@sentry/browser - ES5 CDN Bundle (minified)	65.46 KB (+1.32% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	18.81 KB (-0.27% 🔽)
@sentry/browser - ES6 CDN Bundle (minified)	58.69 KB (+1.26% 🔺)
@sentry/browser - Webpack (gzipped + minified)	23.13 KB (-0.45% 🔽)
@sentry/browser - Webpack (minified)	82.66 KB (+1.16% 🔺)
@sentry/react - Webpack (gzipped + minified)	23.17 KB (-0.45% 🔽)
@sentry/nextjs Client - Webpack (gzipped + minified)	47.95 KB (-0.21% 🔽)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	26.07 KB (-0.03% 🔽)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	24.46 KB (-0.1% 🔽)

[AbhiPrasad]

Looks great!

[Lms24]

For some reason, these two old browser integration tests keep failing:

sentry-javascript/packages/browser/test/integration/suites/api.js

Lines 23 to 62 in 4e722eb

	it('should capture Sentry internal event as breadcrumbs for the following event sent', function () {
	return runInSandbox(sandbox, { manual: true }, function () {
	window.allowSentryBreadcrumbs = true;
	Sentry.captureMessage('a');
	Sentry.captureMessage('b');
	// For the loader
	Sentry.flush && Sentry.flush(2000);
	window.finalizeManualTest();
	}).then(function (summary) {
	assert.equal(summary.events.length, 2);
	assert.equal(summary.breadcrumbs.length, 2);
	assert.equal(summary.events[1].breadcrumbs[0].category, 'sentry.event');
	assert.equal(summary.events[1].breadcrumbs[0].event_id, summary.events[0].event_id);
	assert.equal(summary.events[1].breadcrumbs[0].level, summary.events[0].level);
	});
	});
	it('should capture Sentry internal transaction as breadcrumbs for the following event sent', function () {
	return runInSandbox(sandbox, { manual: true }, function () {
	window.allowSentryBreadcrumbs = true;
	Sentry.captureEvent({
	event_id: 'aa3ff046696b4bc6b609ce6d28fde9e2',
	message: 'someMessage',
	transaction: 'wat',
	type: 'transaction',
	});
	Sentry.captureMessage('c');
	// For the loader
	Sentry.flush && Sentry.flush(2000);
	window.finalizeManualTest();
	}).then(function (summary) {
	// We have a length of one here since transactions don't go through beforeSend
	// and we add events to summary in beforeSend
	assert.equal(summary.events.length, 1);
	assert.equal(summary.breadcrumbs.length, 2);
	assert.equal(summary.events[0].breadcrumbs[0].category, 'sentry.transaction');
	assert.isNotEmpty(summary.events[0].breadcrumbs[0].event_id);
	assert.isUndefined(summary.events[0].breadcrumbs[0].level);
	});
	});

Seems like summary.breadcrumbs has a length of 0. Still working on finding the cause.

[lobsterkatie]

Suggested change

	this.sendEvent(processedEvent);
	this._sendEvent(processedEvent);

This should have stayed _sendEvent, which then itself will call sendEvent. By bypassing _sendEvent, you're also bypassing the super._sendEvent call, so event breadcrumbs are never getting attached. That's why your tests are failing.

[AbhiPrasad]

Good catch! Let's make sure we address this when we get to reviewing the client inheritance chain + looking at all the indirection in the SDK (part 6). We can maybe make the event processing chain smaller and easier to understand.

I made some tickets that went over this.