Request sessions count errors dropped by ignoreErrors or beforeSend #25605

// node repro.mjs <none|handled|ignoreErrors|beforeSend|express-ignoreErrors>
import http from 'node:http';
import zlib from 'node:zlib';

const scenario = process.argv[2];
const sessions = [];
const events = [];
const sink = http.createServer((req, res) => {
  const chunks = [];
  req.on('data', (c) => chunks.push(c));
  req.on('end', () => {
    let body = Buffer.concat(chunks);
    if (req.headers['content-encoding'] === 'gzip') body = zlib.gunzipSync(body);
    const lines = body.toString().split('\n');
    for (let i = 1; i < lines.length; i += 2) {
      try {
        const type = JSON.parse(lines[i]).type;
        if (type === 'sessions') sessions.push(...JSON.parse(lines[i + 1]).aggregates);
        if (type === 'event') events.push(type);
      } catch {}
    }
    res.end('{}');
  });
});
await new Promise((r) => sink.listen(0, '127.0.0.1', r));

const Sentry = await import('@sentry/node');
Sentry.init({
  dsn: `http://key@127.0.0.1:${sink.address().port}/1`,
  release: 'demo@1.0.0',
  ...(scenario === 'ignoreErrors' || scenario === 'express-ignoreErrors' ? { ignoreErrors: ['ExpectedError'] } : {}),
  ...(scenario === 'beforeSend' ? { beforeSend: () => null } : {}),
});
const express = (await import('express')).default;

const app = express();
app.get('/', (req, res) => {
  if (scenario === 'ignoreErrors' || scenario === 'beforeSend') Sentry.captureException(new Error('ExpectedError: not a real problem'));
  if (scenario === 'handled') Sentry.captureException(new Error('real problem'));
  if (scenario === 'express-ignoreErrors') throw new Error('ExpectedError: not a real problem');
  res.send('ok');
});
Sentry.setupExpressErrorHandler(app);
app.use((err, req, res, next) => res.status(500).send('error'));
const server = app.listen(0, '127.0.0.1');
await new Promise((r) => server.once('listening', r));

await fetch(`http://127.0.0.1:${server.address().port}/`).then((r) => r.text());
await Sentry.flush(2000);
await new Promise((r) => setTimeout(r, 300));
const agg = sessions.reduce((a, s) => ({ exited: a.exited + (s.exited || 0), errored: a.errored + (s.errored || 0), crashed: a.crashed + (s.crashed || 0) }), { exited: 0, errored: 0, crashed: 0 });
console.log(`${scenario.padEnd(22)} events sent: ${events.length}   request session: ${JSON.stringify(agg)}`);
server.close(); sink.close();
process.exit(0);