Trap not working

Question

I have a shell script containing trap, but trap doesn't seems to work as expected below is the code and bash version

GNU bash, version 4.2.46(2)-release (x86_64-redhat-linux-gnu)

set -e
function exit_message(){
  echo -e "\e[31m\nError occurred "
}
function login(){
  false
}
trap exit_message ERR
login

Above trap works if I do

function login(){
  trap exit_message ERR
  false
}

Answer 1

From the bash manual:

All [...] aspects of the shell execution environment are identical between a function and its caller with these exceptions: the DEBUG and RETURN traps are not inherited unless the function has been given the trace attribute using the declare builtin or the -o functrace option has been enabled with the set builtin, (in which case all functions inherit the DEBUG and RETURN traps), and the ERR trap is not inherited unless the -o errtrace shell option has been enabled.