# 致命错误：所有协程都处于休眠状态 - 死锁！（所有通道都为 nil 的 select）

- **ID:** `go/goroutine-select-nil-channel`
- **领域:** go
- **类别:** runtime_error
- **验证级别:** ai_generated
- **修复率:** 80%

## 根因

一个 select 语句，其中所有 case 都涉及 nil 通道，导致 select 永远阻塞。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| 1.18 | active | — | — |
| 1.19 | active | — | — |
| 1.20 | active | — | — |
| 1.21 | active | — | — |

## 解决方案

1. **Initialize all channels before select** (100% 成功率)
   ```
   ch1 := make(chan int)
ch2 := make(chan int)
select {
case <-ch1:
case <-ch2:
}
   ```
2. **Use a non-nil channel as a sentinel** (90% 成功率)
   ```
   ch := make(chan int)
close(ch) // closed channel always returns zero value
select {
case <-ch:
}
   ```

## 无效尝试

- **Add a default case to select** — Default case will execute immediately, which may not be desired; also doesn't fix the nil channel issue. (50% 失败率)
- **Check each channel for nil before select** — Can become cumbersome; still need to handle nil channels properly. (60% 失败率)