我遇到了我不了解的Go行为。我的想法是导入一个插件，该插件实现了两个软件包都没有的接口。如果返回一个结构，它可以正常工作，但是要确保它实现了该接口，我想返回一个失败的接口。

接口定义：

package iface

type IPlugin interface{
   SayHello(string)
   SayGoodby(string)
   WhatsYourName() string
}

主程序如下所示：

package main

import (
    "plugin"
    "plugin_test/iface"
    "errors"
    "fmt"
)

//go:generate go build -buildmode=plugin -o ./pg/test.so ./pg/test.go

func main(){
    path := "pg/test.so"
    plug, err := plugin.Open(path)
    if err != nil {
        panic(err)
    }

    sym, err := plug.Lookup("Greeter")
    if err != nil {
        panic(err)
    }

    var pg iface.IPlugin
    pg, ok := sym.(iface.IPlugin)
    if !ok {
        panic(errors.New("error binding plugin to interface"))
    }

    fmt.Printf("You're now connected to: %s \n", pg.WhatsYourName())
    pg.SayHello("user")
    pg.SayGoodby("user")
}

插件（存储在pg / test.go中）

package main

import (
    "fmt"
    "plugin_test/iface"
)

type testpl struct {}

func(pl testpl) SayHello(s string){
    fmt.Printf("Plugin says hello to %s \n", s)
}
func(pl testpl) SayGoodby(s string){
    fmt.Printf("Plugin says goodby to %s \n", s)
}
func(pl testpl) WhatsYourName() string{
    return "my name is Test-Plugin"
}

/* This function works */
func getPlugin() testpl{
    return testpl{}
}

/* This function doesn't work */
func getPlugin() iface.IPlugin{
    return testpl{}
}

/* This function also doesn't work */
func getPlugin() interface{}{
    return testpl{}
}

var Greeter = getPlugin()

我尝试了每个getPlugin功能。

返回的函数将testpl输出预期的输出：

You're now connected to: my name is Test-Plugin
Plugin says hello to user
Plugin says goodby to user

其他功能结束于 sym.(iface.IPlugin)

panic: error binding plugin to interface

goroutine 1 [running]:
main.main()
        /home/../../../main.go:27 +0x343
exit status 2

有人可以解释为什么这不可能吗？如果在这种情况下不让您构建插件，那么创建插件会不会更容易？