Like I said, much of the criticism against interface{} is deserving, but genuinely it works really well for passing generic APIs like Reader / Writer.
The way how interface{} works there is you actually write your own named structure that is bootstrapped by interface{} rather than dealing with interface{} as a generic type that needs casting. So what you're actually working with is an io.Reader / io.Writer structure but which can be transferred to any domain providing your specific implementation of Reader / Writer supports the same methods (since it's the methods that define the interface you avoid all the horrible hacks than normally trouble interface{}). This means you can transfer data from a gzip archive to a base64 encoder or JSON marshaller to a OS STD* file or network device all as if they were the same logical interface and without having to write a lot of additional layers encoding / decoding the data nor describing the interface. It all works surprisingly painlessly. In fact it's literally the only time when working with interface{} that the process isn't painful.
So it's going nothing to do with fanboyism nor stockholm syndrome, interface{} just behaves quite differently to it's usual behavior and works really well in this specific situation in my personal opinion. If the Go developers left interface{} there instead of using it as a hacky alternative to generics then I doubt there would be the same backlash against it. But sadly they didn't.
The way how interface{} works there is you actually write your own named structure that is bootstrapped by interface{} rather than dealing with interface{} as a generic type that needs casting. So what you're actually working with is an io.Reader / io.Writer structure but which can be transferred to any domain providing your specific implementation of Reader / Writer supports the same methods (since it's the methods that define the interface you avoid all the horrible hacks than normally trouble interface{}). This means you can transfer data from a gzip archive to a base64 encoder or JSON marshaller to a OS STD* file or network device all as if they were the same logical interface and without having to write a lot of additional layers encoding / decoding the data nor describing the interface. It all works surprisingly painlessly. In fact it's literally the only time when working with interface{} that the process isn't painful.
So it's going nothing to do with fanboyism nor stockholm syndrome, interface{} just behaves quite differently to it's usual behavior and works really well in this specific situation in my personal opinion. If the Go developers left interface{} there instead of using it as a hacky alternative to generics then I doubt there would be the same backlash against it. But sadly they didn't.