# 恐慌：运行时错误：从 nil 通道接收

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

## 根因

尝试从 nil 通道接收，导致永久阻塞，但如果 select 中有 default 可能不会恐慌；然而直接接收会恐慌。

## 版本兼容性

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

## 解决方案

1. **Initialize channel before use** (100% 成功率)
   ```
   ch := make(chan int); go func() { ch <- 1 }(); val := <-ch
   ```
2. **Use select with default to handle nil channel gracefully** (90% 成功率)
   ```
   select { case val := <-ch: use(val); default: // skip }
   ```

## 无效尝试

- **Checking ch == nil before receive and returning** — Check prevents panic but may cause silent data loss. (30% 失败率)
- **Using recover to catch panic** — Panic is recoverable but indicates logic error; data not received. (50% 失败率)