“构造函数"应否函数返回错误或空值? [英] Should a "constructor" function return an error or a null value?

问题描述

给出一个构造函数，例如

Given the a constructor function such as

func NewSomething(name, color string) *Something {
    s := Something{name, color}
    return &s
}

此功能是否应包含健全性检查，例如& name == nil 或 len(name)== 0 ?如果此函数应包含完整性检查，则构造函数应返回什么值? nil 值还是错误( errors.New(...))?下面包括一个示例.

Should this function include sanity checks, such as &name == nil, or len(name) == 0? If this function should contain sanity checks, what value should be returned from the constructor? A nil value, or an error (errors.New(...))? An example is included below.

func NewSomething(name, color string) *Something {
    if &name == nil || len(name) == 0 {
        return nil
    }

    if &color== nil || len(color) == 0 {
        return nil
    }

    s := Something{name, color}
    return &s
}

推荐答案

返回错误.使用可分辨的值(例如 nil )来指示错误不是惯用的.

Return an error. It is not idiomatic to use a distinguished value (such as nil) to indicate an error.

func NewSomething(name, color string) (*Something, error) {
  if name == "" {
    return nil, errors.New("bad name")
  }

  if color == "" {
    return nil, errors.New("bad color")
  }

  s := Something{name, color}
  return &s, nil
}

此外:表达式& anyVariable == nil 始终求值为 false .将检查简化为 len(color)== 0 或 color ==" .

Aside: The expression &anyVariable == nil always evaluates to false. Simplify the checks to len(color) == 0 or color == "".

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