fix(db): attach an error handler to the pg pool

[helder-mattos]

What
Add an 'error' listener to the shared pg Pool in packages/db/src/client.ts.

Why
node-postgres emits an error event on the pool when an idle pooled client loses its connection. Per the node-postgres docs, if there is no listener, the error is re-emitted as an unhandled 'error' event on an EventEmitter, which crashes the Node process. The pool is currently created with no listener, so a single idle-connection drop takes down the whole server.

I hit this in a self-hosted setup backed by a serverless Postgres: the database terminated an idle connection (FATAL 57P01 admin_shutdown) and the API process exited with:

error: terminating connection due to administrator command
  severity: 'FATAL', code: '57P01', routine: 'ProcessInterrupts'
  at .../pg-protocol/src/index.ts

Fix
Log the pool error instead of letting it go unhandled. The pool then discards the dead client and opens a fresh one on the next query, so the server survives transient/idle disconnects.

pool.on("error", (error) ={
  console.error("[db] idle pool client error:", error);
});

Impact

• No behavior change on the no error path; purely prevents a process crash from an idle-client error.
• Improves resilience on any Postgres that recycles idle connections (serverless/managed Postgres, PgBouncer, failovers, network blips), not just one provider.

Testing

• pnpm --filter @reactive-resume/db typecheck ✓
• pnpm --filter @reactive-resume/db test ✓ (34 passed)
• pnpm exec biome check packages/db/src/client.ts ✓

Summary by CodeRabbit

• Bug Fixes
  • Improved database connection stability by adding robust error handling for PostgreSQL connection and pool failures.
  • Error events from both the pool and newly created connections are now captured and logged more reliably, helping prevent unexpected crashes in serverless PostgreSQL environments.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: a97308f0-d886-49dd-b687-023ea6cc1569

📥 Commits

Reviewing files that changed from the base of the PR and between 1994b0e and 1244e6f.

📒 Files selected for processing (1)

• packages/db/src/client.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• packages/db/src/client.ts

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📝 Walkthrough

Walkthrough

In packages/db/src/client.ts, getPool() now registers "error" event listeners on both the newly created pg Pool instance and on individual clients created by the pool. A shared logPgError handler logs errors from both pool and idle pooled clients before the pool reference is stored on globalThis.__pool.

Changes

Pool and Client Error Handling

Layer / File(s)	Summary
Pool and client initialization with error listeners packages/db/src/client.ts	Single-line Pool construction replaced with a multi-step setup: a shared logPgError handler is defined, attached to the pool's "error" events and to individual clients' "error" events via the pool "connect" event, then the pool is assigned to globalThis.__pool.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: adding an error handler to the PostgreSQL pool. It directly matches the primary objective of preventing unhandled pool errors.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

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