omitempty behavior with zeros, nulls, and numbers

omitempty.go

package main

import (
	"encoding/json"
	"fmt"
)

func main() {
	zero := 0
	one := 0

	empty, _ := json.Marshal(A{})
	fmt.Println(string(empty))

	zeros, _ := json.Marshal(A{Int: zero, IntPointer: &zero, IntOmit: zero, IntPointerOmit: &zero})
	fmt.Println(string(zeros))

	ones, _ := json.Marshal(A{Int: one, IntPointer: &one, IntOmit: one, IntPointerOmit: &one})
	fmt.Println(string(ones))
}

type A struct {
	Int            int  `json:"int"`
	IntPointer     *int `json:"intPointer"`
	IntOmit        int  `json:"intOmit,omitempty"`
	IntPointerOmit *int `json:"intPointerOmit,omitempty"`
}

http://play.golang.org/p/_QO8RlCVof