support non empty interface

[mailru]

support non empty interface

[rvasily]

Can you provide sample code?

[sreekanth-cb]

type MyInterface interface {
        Hello() string
}

type MyString string

func (ms MyString) Hello() string {
        return string(ms)
}

type TestObject struct {
                Field MyInterface
 }
func main() {
	obj := TestObject{}
	obj.Field = MyString("AAA")
	b, _ := json.Marshal(&obj)
	fmt.Println("OP->", string(b))
	
}

easyjson code generation fails here with error
interface type MyInterface not supported: only interface{} is allowed.
Can you please let me know whether easyjson will fix this api/service break with std json?

[mkabischev]

It is impossible to do it without reflection, so I think the only way is to generate code that will run default (reflection-based) marshaller for this field.

[rvasily]

I think it possible to have just a little bit of reflection overhead in stdlib marshaler if MyString will have generaded marshallers with easyjson ( implements json.Marshaler interface )

[sparques]

My preference would be if easyjson doesn't support something (such as a non-empty interface) fallback on the standard json.Marshal. There could be a switch to enable this behavior and the default can be off (for backwards compatibility sake).

[dgoodine]

@GoWebProd Why was this closed? I think @deusnefum's suggestion is not unreasonable.

[dgoodine]

It should also be noted that the error generated by easyjson give absolutely no context as to where the error occurred in the source file.

[GoWebProd]

@dgoodine Hello, issue closed because easyjson not supports non-empty interfaces due to the lack of the ability to use reflect lib. If you want to use interface in struct, please set type to interface{} (empty interface)

[dgoodine]

Why can't easyjson use the reflect lib? At least just for those fields whose type is an interface.

[GoWebProd]

The task of easyjson is parsing and serialization quickly. Reflect does not allow this.