Force account creation by category or tag

function sumobi_edd_force_account_creation_by_download_category_or_tag( $ret ) {

	// download categories that the download must belong to before account creation is forced

	$categories_to_search = array( 'cat1', 'cat2', 'cat3' );

	// download tags that the download must belong to before account creation is forced

	$tags_to_search       = array( 'tag1', 'tag2' );

	// get our cart contents

	$cart = edd_get_cart_contents();

	if ( $cart ) {

		// create an array with all our download IDs

		$download_ids = wp_list_pluck( $cart, 'id' );

		if ( $download_ids ) {

			// loop through IDs and check if they belong to any of the categories or tags

			foreach ( $download_ids as $id ) {

				if ( has_term( $categories_to_search, 'download_category', $id ) || has_term( $tags_to_search, 'download_tag', $id ) ) {

					// found one, force account creation

					$ret = (bool) true;

				}

			}

		}

	}

	return $ret;

}

add_filter( 'edd_no_guest_checkout', 'sumobi_edd_force_account_creation_by_download_category_or_tag' );