I encountered an issue with struct A and B while unmarshalling JSON strings. When a JSON string meant for struct A is unmarshalled correctly, it works fine. However, if the same JSON string is mistakenly unmarshalled into struct B, it still succeeds (which is incorrect).
Is there a way to detect when the wrong JSON input has been erroneously converted to the wrong struct type?
You can review the code provided at: play
package main
import (
"encoding/json"
"fmt"
)
type A struct {
Name string `json:"name"`
Age int `json:"age"`
}
type B struct {
Alamat string `json:"alamat"`
Umur int `json:"umur"`
}
func main() {
var structA A
var structAA A
valA := "{\"name\":\"budi\",\"age\":10}"
valB := "{\"alamat\":\"jakarta\",\"umur\":120}"
//correct case
err := json.Unmarshal([]byte(valA), &structA)
if err != nil {
fmt.Println("fail unmarshal")
}
fmt.Println(structA.Name)
fmt.Println(structA.Age)
//unmarshalled successfully but with wrong json
err = json.Unmarshal([]byte(valB), &structAA)
if err != nil {
fmt.Println("fail unmarshal")
}
fmt.Println(structAA.Name)
fmt.Println(structAA.Age)
}