rvm/extras/bash_zsh_support/chpwd/function.sh

function.sh

__zsh_like_cd()
{
    # Called as:
    #    cd()    { __zsh_like_cd cd    "$@" ; }
    #    popd()  { __zsh_like_cd popd  "$@" ; }
    #    pushd() { __zsh_like_cd pushd "$@" ; }
    # So, "$@" in __zsh_like_cd contains the __zsh_like_cd "personality" as well as passed arguments
  \typeset __zsh_like_cd_hook # define local variable in __zsh_like_cd scope, may be POSIXly correct but lol- #! is /bin/bash, use "local __zsh_like_cd_hook". Also, hilarious that they prepend \ to typeset because who knows if you can trust that it's not hooked!
  if
    builtin "$@" # builtin returns true if command is a built-in
  then
    shift || true # remove the called "personality", such as cd, pushd, or popd
    for __zsh_like_cd_hook in chpwd "${chpwd_functions[@]}" # no idea where chpwd is defined, git grep "function chpwd" returns nothing. Apparently this means something in zsh but this is definitely supposed to executed with bash, in fact, this whole function is hacking a zsh feature into bash
    do
      if \typeset -f "$__zsh_like_cd_hook" >/dev/null 2>&1 # if the hooked binary is a shell function
      then "$__zsh_like_cd_hook" "$@" || break # call each hooked shell function with passed arguments and break on first failed function call
      fi
    done
    true # override return value of last hooked shell function
  else
    return $? # return value of $(builtin "$@") for some reason
  fi
}