# http：多余的 response.WriteHeader 调用，来自 main.handler（server.go:42）

- **ID:** `go/http-superfluous-writeheader`
- **领域:** go
- **类别:** runtime_error
- **验证级别:** ai_generated
- **修复率:** 80%

## 根因

WriteHeader 被调用多次，或在 WriteHeader 之前调用了 Write。只有第一个状态码会被发送。

## 版本兼容性

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

## 解决方案

1. **** (90% 成功率)
   ```
   if !wroteHeader { w.WriteHeader(http.StatusOK); wroteHeader = true }
json.NewEncoder(w).Encode(v)
   ```
2. **** (88% 成功率)
   ```
   Return early after writing an error status; never write body after WriteHeader without checking.
   ```

## 无效尝试

- **** — Hides a real bug; the wrong status code may be sent to clients. (80% 失败率)
- **** — Does not fix the underlying control flow. (70% 失败率)