# 恐慌：同步：负数WaitGroup计数器

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

## 根因

调用Done()的次数超过Add()，导致WaitGroup计数器变为负数。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| 1.0 | active | — | — |
| 1.22 | active | — | — |

## 解决方案

1. **Ensure Add is called exactly once per goroutine before Done** (95% 成功率)
   ```
   var wg sync.WaitGroup
for i := 0; i < 10; i++ {
    wg.Add(1)
    go func() {
        defer wg.Done()
        // work
    }()
}
wg.Wait()
   ```
2. **Use defer wg.Done() immediately after wg.Add()** (98% 成功率)
   ```
   wg.Add(1)
go func() {
    defer wg.Done()
    // work
}()
   ```

## 无效尝试

- **Using recover() to catch panic and continue** — Panic indicates misuse; recovering doesn't fix the counter imbalance. (90% 失败率)
- **Adding extra Add() calls to compensate** — Race condition may cause unpredictable counter values; proper accounting is needed. (80% 失败率)