Output compex structs as JSON for diff (for example in Jetbrains Goland)

main.go

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"math/rand"
	"path/filepath"
)

func main() {
	expected, actual := "expected", "actual"
  // 👇 copy and paste this code to output files and debug them.
  //    (note that **/rob-only-* is in my ~/.gitignoreglobal)
	
	// TODO DEBUG DIFF REMOVE ME
	(func(expected, actual interface{}) {
		contents := map[string][]byte{}
		id := rand.Uint32()
		for name, v := range map[string]interface{}{
			"expected": expected,
			"actual":   actual,
		} {
			contents[name], _ = json.MarshalIndent(v, "", "  ")
		}
		if bytes.Compare(contents["expected"], contents["actual"]) != 0 {
			paths := []string{}
			for name, j := range contents {
				fileName := fmt.Sprintf("rob-only-%d-%s.json", id, name)
				_ = ioutil.WriteFile(fileName, j, 0777)
				abs, _ := filepath.Abs(fileName)
				paths = append(paths, abs)
			}
			panic(fmt.Sprintf("CONTENTS ARE DIFFERENT:\n%s\n%s", paths[0], paths[1])))
		}
	})(expected, actual)
}