puppet resource ordering via require metaparameter fails to work

In my puppet configuration, I've got a defined resource type as follows. Everything was working fine under puppet 2.7, but after an upgrade to puppet 3.8, I'm having trouble with it. When I create a user, the exec runs without the user and group running first, so the exec resource's command fails to execute properly.

Can anyone explain what is going wrong?

define my_user (
  $uid,
  $fullname,
  $email,
  $group = $name,
  $ingroups = [],
  $shell = '/bin/bash',
  $home = "/home/${name}",
  $ensure = 'present',
  $sudo = 'no',
  $system_user = false,
  $ssh_key = undef,
  $ssh_key_type = undef,
) {

  group{ $name:
    ensure => present,
    gid    => $uid,
  }

  user { $name:
    ensure     => $ensure,
    comment    => $fullname,
    uid        => $uid,
    gid        => $group,
    groups     => $ingroups,
    shell      => $shell,
    home       => $home,
    managehome => true,
    require    => Group[$group],
    system     => $system_user,
  }

  exec { "${name} homedir":
    command => "/bin/cp -R /etc/skel ${home}; /bin/chown -R ${name}:${group} ${home}",
    creates => $home,
    require => User[$name],
  }

  file { "${home}/.ssh":
    ensure  => directory,
    require => [ User[$name], Exec["${name} homedir"] ],
    owner   => $name,
    group   => $name,
    mode    => '0755',
  }

  if $ssh_key {
    ssh_authorized_key{ $email:
      ensure => $ensure,
      user   => $name,
      key    => $ssh_key,
      type   => $ssh_key_type,
    }
  }
}