cobra failing to mark flag as required

I have the following flag addition in a cobra.Cmd

	myCmd.PersistentFlags().StringP(applicationLongFlag, applicationShortFlag, applicationDefaultValue, applicationFlagHelpMsg)

Where

	applicationLongFlag     = "application"
	applicationShortFlag    = "a"
	applicationDefaultValue = ""
	applicationFlagHelpMsg  = "The application name"

This works as expected, however when trying to make the above flag as required the process fails

	if err := myCmd.MarkFlagRequired(applicationShortFlag); err != nil {
		return errors.Wrapf(err, "error marking %s as required flag", applicationShortFlag)
	}

error marking a as required flag: no such flag -a

-a / --application works as expected and it is also printed in my help

▶ go run myprog.go mycommand --help

Usage:
  myprog.go mycommand [flags]

Flags:
  -a, --application string   The application name

Why is it failing to be set as required?

I think you should use MarkPersistentFlagRequired instead of MarkFlagRequired as you are trying to mark a persistent flag.
You can only use name of the flag and not the shorthand.

Code

package main

import (
	"fmt"

	"github.com/spf13/cobra"
)

func main() {
	rootCmd := &cobra.Command{
		Use: "root",
		Run: func(cmd *cobra.Command, args []string) {
			fmt.Println("Mark using `MarkPersistentFlagRequired` ")
		},
	}

	rootCmd.PersistentFlags().StringP("test", "t", "", "test required")
    // Change this
	if err := rootCmd.MarkPersistentFlagRequired("test"); err != nil {
		fmt.Println(err.Error())
		return
	}
	rootCmd.Execute()
}

Output

⇒  go run main.go 
Error: required flag(s) "test" not set
Usage:
  root [flags]

Flags:
  -h, --help          help for root
  -t, --test string   test required