How to create a deep copy of a struct using reflection in Golang?

To create a deep copy of a struct using reflection in Go, you can follow the steps below:

Import the necessary packages:

import (
    "reflect"
)

Create a function that takes the struct instance as a parameter and returns a copy of it:

func DeepCopy(src interface{}) interface{} {
    // Get the type of the source struct
    srcType := reflect.TypeOf(src)

    // Create a new instance of the source struct type
    dest := reflect.New(srcType).Elem()

    // Get the value of the source struct
    srcValue := reflect.ValueOf(src)

    // Iterate over the fields of the source struct
    for i := 0; i < srcValue.NumField(); i++ {
        // Get the field value and type of the source struct
        fieldValue := srcValue.Field(i)
        fieldType := srcType.Field(i)

        // Create a deep copy of the field value
        fieldCopy := reflect.New(fieldValue.Type()).Elem()
        if fieldValue.Kind() == reflect.Struct {
            fieldCopy.Set(reflect.ValueOf(DeepCopy(fieldValue.Interface())))
        } else {
            fieldCopy.Set(fieldValue)
        }

        // Set the copied field value in the new struct
        dest.FieldByName(fieldType.Name).Set(fieldCopy)
    }

    // Return the copy of the struct
    return dest.Interface()
}

Call the DeepCopy function and pass the struct instance as an argument:

type Person struct {
    Name string
    Age  int
    Addr Address
}

type Address struct {
    Street string
    City   string
    State  string
}

func main() {
    p1 := Person{Name: "Alice", Age: 25, Addr: Address{Street: "123 Main St", City: "City1", State: "State1"}}

    p2 := DeepCopy(p1).(Person)

    fmt.Println(p1) // {Alice 25 {123 Main St City1 State1}}
    fmt.Println(p2) // {Alice 25 {123 Main St City1 State1}}

    // Modify a field in p2
    p2.Name = "Bob"
    p2.Addr.City = "City2"

    fmt.Println(p1) // {Alice 25 {123 Main St City1 State1}}
    fmt.Println(p2) // {Bob 25 {123 Main St City2 State1}}
}

This code will create a deep copy of the Person struct instance p1 and assign it to p2. Any modifications made to p2 will not affect p1, ensuring a true deep copy.