Go 常见错误

100 Go Mistakes and How to Avoid Them

《100 Go Mistakes and How to Avoid Them》这本书的一些重要内容笔记。

2 Code and project organization

2.1 #1: Unintended variable shadowing

    var client *http.Client // 以下代码运行后，client 依然还是 nil
    if tracing {
            // Declares a client variable
            client, err := createClientWithTracing() // 新创建的同名变量覆盖外层同名的 client
            if err != nil {
                    return err
            }
            log.Println(client)
    } else {
            client, err := createDefaultClient()
            if err != nil {
                    return err
            }
            log.Println(client)
    }

// 解决方式：不要使用 := 赋值一个新变量，需要声明一下 client 和 err
    var client *http.Client
    var err error // Declares an err variable
    if tracing {
            client, err = createClientWithTracing()
            if err != nil {
                    return err
            }
    } else {
            // Same logic
    }

2.5 #5: Interface pollution

When to use interfaces:

• Common behavior

• Decoupling

• Restricting behavior