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go.empty_critical_section

Performance Medium

Detects mutex locks protecting empty or trivial critical sections, causing unnecessary contention.

Why It Matters

Empty critical sections cause:

Unnecessary contention - Goroutines block for nothing
Deadlock risk - Complex lock patterns with no benefit
Performance degradation - Lock overhead without protection
Code smell - Often indicates incomplete implementations

Example

// ❌ Before (pointless locking)
var mu sync.Mutex

func process() {
    mu.Lock()
    defer mu.Unlock()
    // Nothing protected!
}

// Also problematic
func update() {
    mu.Lock()
    mu.Unlock() // Immediate unlock
    doWork() // Work happens outside lock
}

// ✅ After (meaningful critical section)
var mu sync.Mutex
var counter int

func process() {
    mu.Lock()
    defer mu.Unlock()
    counter++ // Actually protected
}

What Unfault Detects

Lock()/Unlock() with nothing between them
defer mu.Unlock() with no protected operations
Critical sections with only logging
Lock/unlock without shared state access

Auto-Fix

Unfault flags these for manual review since the fix depends on intent:

// Option 1: Remove unnecessary lock
func process() {
    doWork() // If no shared state
}

// Option 2: Add protected operations
func process() {
    mu.Lock()
    sharedData = newValue
    mu.Unlock()
    doWork()
}