net/url: URL.Clone, Values.Clone

// This program demonstrates the new Clone methods for net/url.URL and url.Values.
// It runs in Go 1.27.1 and shows how to copy a URL and its query parameters safely.
package main

import (
	"fmt"
	"net/url"
)

func main() {
	// Original URL with user info and query parameters.
	orig, _ := url.Parse("https://user:[email protected]/path?foo=bar&baz=qux")

	// Clone the URL. The returned value is a deep copy, including the User field.
	cloned := orig.Clone()

	// Modify the clone: change the path and add a query value.
	cloned.Path = "/newpath"
	cloned.Query().Set("new", "value")

	// Show that the original URL is unchanged.
	fmt.Println("Original:", orig.String())
	fmt.Println("Cloned :", cloned.String())

	// Clone the query values separately.
	origVals := orig.Query()
	clonedVals := origVals.Clone()

	// Modify the cloned values.
	clonedVals.Set("foo", "changed")

	// The original values remain untouched.
	fmt.Println("Original query:", origVals.Encode())
	fmt.Println("Cloned query  :", clonedVals.Encode())
}