R12.5: Database connection pool hygiene

Short answer: Acquired pool clients release in finally blocks. A pool client that is not released starves the pool, and the app stops answering.

Group: Memory and resource leaks. Status: stable. Generated from the rule definitions; do not edit by hand.

Playground: https://brevio.pro/tools/agent-guard-playground?rule=R12.5

What it catches

Database connection pool hygiene: acquired pool clients release in finally blocks.

Why

A pool client that is not released starves the pool, and the app stops answering.

A bad example

const c = await pool.connect(); await c.query(q);

A good example

const c = await pool.connect();
try { await c.query(q); } finally { c.release(); }

How it is checked

Nothing yet. No scanner and no slice card checks it: it is a standing rule for authors and reviewers.

How to silence it

A person can silence one finding with brevio-core: ignore R12.5 -- reason on the line or the line above. Without the reason it does not count. An agent cannot silence it: the agent hook and the MCP tools never honour the comment, and a pull request that adds one is reported until a reviewer allows it. Fixing the code is still the better answer.

To change what the rule flags, edit its definition in dev_rules.py or code_rules/__init__.py. That is a code change and is reviewed like one.

R12.6 Worker thread termination
R12.7 Temp file deterministic deletion
R12.8 No unbounded collection growth
R12.1 Event listener teardown
Every rule