# 恐慌：同步：WaitGroup在之前的Wait返回之前被重用

- **ID:** `go/goroutine-waitgroup-wait-in-loop`
- **领域:** go
- **类别:** runtime_error
- **验证级别:** ai_generated
- **修复率:** 80%

## 根因

在之前的Wait()仍在进行时对WaitGroup调用Add()，导致竞态条件。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| 1.0 | active | — | — |
| 1.20 | active | — | — |

## 解决方案

1. **Create a new WaitGroup for each batch** (95% 成功率)
   ```
   for batch := 0; batch < 3; batch++ {
    var wg sync.WaitGroup
    for i := 0; i < 5; i++ {
        wg.Add(1)
        go func() { defer wg.Done(); /* work */ }()
    }
    wg.Wait()
}
   ```
2. **Use channels to synchronize instead of reusing WaitGroup** (85% 成功率)
   ```
   ch := make(chan struct{})
for i := 0; i < 5; i++ {
    go func() { /* work */; ch <- struct{}{} }()
}
for i := 0; i < 5; i++ {
    <-ch
}
   ```

## 无效尝试

- **Using recover() to catch panic** — Panic is unrecoverable in this context; program crashes. (100% 失败率)
- **Adding more Done() calls to unblock Wait** — Counter imbalance causes negative counter panic. (90% 失败率)