Backend Code Smells

try { return await enrich(id) }
catch { return {} }

const ctl = new AbortController()
const t = setTimeout(() => ctl.abort(), 800)
try {
  return await enrich(id, ctl.signal)
} catch (err) {
  metrics.inc('enrich.failed', { reason: classify(err) })
  log.warn({ err, id }, 'profile enrichment failed; serving without it')
  return PROFILE_UNAVAILABLE   // an explicit, typed absence
} finally {
  clearTimeout(t)
}

Both continue serving the request. Only the second one is *visible*: the failure has a bounded duration, a counter that alerts, a log line with the correlating id, and a return value the caller can distinguish from "this user has an empty profile".

1async function enrich(userId: string) {
2  try {
3    // no timeout: if the provider hangs, this request hangs,
4    // holding a pool connection and a loop slot until something
5    // upstream gives up. Under load, every slot ends up here.
6    const res = await fetch(`${PROFILE_API}/users/${userId}`)
7    return await res.json()
8  } catch {
9    // and if it fails, we return nothing, forever, silently.
10    // No metric increments. No log line. The dashboard is green.
11    return {}
12  }
13}

The catch block is the more dangerous of the two. A hang eventually pages someone; a silent empty object produces a product bug that is reported months later as "profiles sometimes do not load" and cannot be reproduced.

• What happens if this never returns? — finds missing timeouts and unbounded holds.
• What happens if this throws? — finds swallowed errors and half-completed writes (Where the Transaction Boundary Goes).
• What is the largest N here, and who controls it? — finds unbounded concurrency and unpaginated queries.
• How many network calls does this line make? — finds hidden lazy loads and N+1.
• Is this shared between concurrent requests? — finds global mutable state and per-request context leaks.
• Where is the authorization check, and does every branch pass through it? — finds the gap fat controllers create.
• What change would this structure make hard next quarter? — the only honest test for a structural smell.