Empty Catch Block Finder

Detect silent error handlers that cause mysterious production failures.

Why This Matters

Empty catch blocks are silent killers:

try {
  await saveOrder(order);
} catch (e) {
  // Silent failure - order lost, no evidence
}

This skill finds them before they cause production incidents.

Quick Start

Empty Catch Analysis:
- [ ] Step 1: Scan for empty catch blocks
- [ ] Step 2: Assess risk level
- [ ] Step 3: Generate fix suggestions

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Workflow

Step 1: Scan for Empty Catches

Find all empty/silent catch blocks:

python scripts/find_empty_catches.py <directory>

Detects:

• catch (e) {} - completely empty
• catch (e) { /* comment */ } - only comments
• except: pass - Python silent pass
• if err != nil { } - Go ignored errors
• catch { return; } - silent returns

Step 2: Assess Risk Level

Each catch is categorized by risk:

Risk	Pattern	Why Dangerous
🔴 Critical	Empty catch in async/database code	Data loss, corruption
🟠 High	Empty catch in API handlers	Silent failures to users
🟡 Medium	Empty catch in utilities	Hidden bugs
🟢 Low	Empty catch in tests/scripts	Usually intentional

Step 3: Generate Fix Suggestions

Get suggested fixes:

python scripts/generate_fixes.py <directory> --output fixes.md

Fix patterns:

// ❌ Before: Silent failure
catch (e) {}

// ✅ After: Logged + handled
catch (e) {
  logger.error('Order save failed', { error: e, orderId: order.id });
  throw new OrderSaveError('Failed to save order', { cause: e });
}

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Utility Scripts

Script	Purpose
find_empty_catches.py	Find empty catch blocks
generate_fixes.py	Suggest proper error handling

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Language Support

Language	Patterns Detected
JavaScript/TypeScript	catch (e) {}, catch {}
Python	except: pass, except Exception: ...
Java	catch (Exception e) {}
Go	if err != nil { } (empty body)
C#	catch (Exception) {}

See PATTERNS.md for full pattern reference.

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Example

User: "Find silent error handlers in my codebase"

Output:

Found 8 empty catch blocks

🔴 CRITICAL (2)
  src/services/payment.ts:45
    catch (e) {} // In async payment processing!

  src/db/users.ts:112
    catch (e) { return null; } // Hides DB errors

🟠 HIGH (3)
  src/api/orders.ts:78
    catch (error) { /* TODO: handle */ }

  ...

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Integration with Linting

After fixing, prevent new empty catches:

ESLint:

{ "rules": { "no-empty": ["error", { "allowEmptyCatch": false }] } }

Python (Ruff):

[tool.ruff]
select = ["E722"]  # bare-except

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Related Skills

• incident-response-helper — Debug issues caused by silent failures
• stale-todo-finder — Find // TODO: handle error comments