# 恐慌：向已关闭的通道发送数据（发送者在关闭后发送）

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

## 根因

发送者协程在另一个协程关闭通道后发送数据，通常由于竞态条件。

## 版本兼容性

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

## 解决方案

1. **Use a done channel to signal senders to stop** (85% 成功率)
   ```
   done := make(chan struct{})
ch := make(chan int)
go func() {
    for {
        select {
        case <-done:
            return
        case ch <- 1:
        }
    }
}()
close(ch) // but close done first
close(done)
   ```
2. **Use sync.WaitGroup to ensure all sends complete before close** (90% 成功率)
   ```
   var wg sync.WaitGroup
for i := 0; i < 5; i++ {
    wg.Add(1)
    go func() {
        defer wg.Done()
        ch <- 1
    }()
}
wg.Wait()
close(ch)
   ```

## 无效尝试

- **Using recover() to catch panic and log** — Recover doesn't fix the race; data may be lost. (90% 失败率)
- **Checking channel length before send** — len(ch) doesn't indicate closed state; send still panics. (95% 失败率)