The Get function is not thread-safe. Concurrent calls may lead to race conditions or data corruption.

[Ap0k]

Describe the bug

func (cache *Cache) Get(key string) (any, bool) {
	cache.mutex.Lock()
	entry, ok := cache.get(key)
	if !ok {
		cache.stats.Misses++
		cache.mutex.Unlock()
		return nil, false
	}
	if entry.Expired() {
		cache.stats.ExpiredKeys++
		cache.delete(key)
		cache.mutex.Unlock()
		return nil, false
	}
	cache.stats.Hits++
	if cache.evictionPolicy == LeastRecentlyUsed {
		entry.Accessed()
		if cache.head == entry {
			cache.mutex.Unlock() // The mutex is released before the work with the shared data has finished.
			return entry.Value, true // !!!RACE detection
		}
		// Because the eviction policy is LRU, we need to move the entry back to HEAD
		cache.moveExistingEntryToHead(entry)
	}
	cache.mutex.Unlock() // The mutex is released before the work with the shared data has finished.
	return entry.Value, true // !!!RACE Detection
}

What do you see?

Better to rewrite the function as follows:

func (cache *Cache) Get(key string) (any, bool) {
	cache.mutex.Lock()
	defer cache.mutex.UnLock()
	entry, ok := cache.get(key)
	if !ok {
		cache.stats.Misses++
		return nil, false
	}
	if entry.Expired() {
		cache.stats.ExpiredKeys++
		cache.delete(key)
		return nil, false
	}
	cache.stats.Hits++
	if cache.evictionPolicy == LeastRecentlyUsed {
		entry.Accessed()
		if cache.head == entry {
			return entry.Value, true
		}
		// Because the eviction policy is LRU, we need to move the entry back to HEAD
		cache.moveExistingEntryToHead(entry)
	}
	return entry.Value, true
}

What do you expect to see?

No response

List the steps that must be taken to reproduce this issue

No response

Version

No response

Additional information

No response