Go语言中互斥锁的奇葩BUG如何解决？

fmt.Println("1. 开始加锁:", key)
s.Lock()
fmt.Println("2. 加锁完成:", key)

defer fmt.Println("4. 开始解锁:", key)
defer s.Unlock()
defer fmt.Println("5. 解锁完成:", key)

package category

import (
    "sync"
)

type Sync struct {
    name string
    age  int
    mu   sync.Mutex
}

var (
    cache          *Sync
    cacheContainer Sync
)

// gettree 查询列表 (错误示例)
func (s *Sync) gettree() *Sync {
    s.mu.Lock()
    defer s.mu.Unlock()
    cache = &Sync{
        name: "abc",
        age:  18,
    }
    // 此处错误：cachecontainer指向cache的副本，并非cache本身
    cacheContainer = *cache
    return &cacheContainer
}

// gettree2 查询列表 (正确示例)
func (s *Sync) gettree2() *Sync {
    s.mu.Lock()
    defer s.mu.Unlock()
    cache = &Sync{
        name: "abc",
        age:  18,
    }
    return cache
}

// gettree 修正后的版本
func (s *Sync) gettree() *Sync {
    s.mu.Lock()
    defer s.mu.Unlock()
    cache = &Sync{
        name: "abc",
        age:  18,
    }
    return cache
}

func gettree(s *Sync) *Sync {
    s.mu.Lock()
    defer s.mu.Unlock()
    newCache := &Sync{name: "abc", age: 18}
    return newCache
}