README.md

defensive.empty-catch

Flags empty catch blocks that silently suppress failures.

• Family: defensive
• Severity: strong
• Scope: file
• Requires: file.tryCatchSummaries

How it works

The rule reports small try/catch blocks when the catch body is empty. It intentionally skips:

• common filesystem-existence probes
• documented local fallbacks where the try block only resolves local values and the catch explains that execution should fall through to another source
• larger try blocks where this structural approximation is less trustworthy

Flagged example

export function parseConfig(raw: string) {
  try {
    return JSON.parse(raw);
  } catch {}

  return null;
}

Usually ignored

export function loadTheme() {
  let stored: string | null = null;

  try {
    stored = localStorage.getItem("theme");
  } catch {
    // fall through to the default theme
  }

  return stored ?? "light";
}

How to fix / do this better

An empty catch should usually become one of these instead:

• rethrow the error
• return a deliberate typed fallback with a comment explaining the boundary behavior
• log meaningful context and then rethrow
• validate earlier so the exceptional path is narrower and more intentional

export function parseConfig(raw: string) {
  try {
    return JSON.parse(raw);
  } catch (error) {
    throw new Error("Invalid config JSON", { cause: error });
  }
}

If swallowing the error is truly intentional, document why the fallback is safe and keep the scope local.

Scoring

Each flagged catch uses the shared try/catch scoring helper, then the file total is capped at 8. Boundary-oriented catches are downweighted instead of fully ignored.

Benchmark signal

Small pinned rule benchmark (manifest):

• Signal rank: #5 of 9
• Signal score: 0.67 / 1.00
• Best separating metric: findings / file (0.93)
• Hit rate: 6/6 AI repos vs 5/5 mature OSS repos
• Full results: rule signal report