Part of the new Users.pm controller

sub signup_email {
  my ($c) = @_;
  my $v = $c->validation;

  try {
    Bugzilla::User->new->check_account_creation_enabled;
    my $email_regexp = Bugzilla->params->{createemailregexp};
    $v->required('email')->like(qr/$email_regexp/);
    $v->csrf_protect;

    ThrowUserError('account_creation_restricted') unless $v->is_valid;

    my $email  = $v->param('email');
    Bugzilla::User->check_login_name_for_creation($email);
    Bugzilla::Hook::process("user_verify_login", {login => $email});

    $c->issue_new_user_account_token($email);
    $c->render(handler => 'bugzilla');
  }
  catch {
    $c->bugzilla->error_page($_);
  };
}