Allow all downloads in a EDD bundle to use a sinle license

allow_single_license.php

<?php
/**
 * Allow multiple downloads in a bundled Easy Digital Downloads
 * product be updated from a single license
 * 1. Create 1 download set to generate a license
 * 2. Create more downloads and do not set them to generate licenses
 * 3. Create one more download and bundle all the downloads from #1 and #2
 */

function s11_allow_single_license() {
	if ( isset( $_POST['item_id'] ) && isset( $_POST['item_name'] ) && isset( $_POST['license'] ) ) {
		$license = sanitize_text_field( $_POST['license'] );
		$download_id = edd_software_licensing()->get_download_by_license( $license );
		$item_id = absint( $_POST['item_id'] );

		if ( $download_id != $item_id ) {
			// check if this product is in the same bundle
			global $wpdb;
			$query = $wpdb->prepare( 'SELECT meta_value FROM ' . $wpdb->postmeta . ' WHERE meta_key = %s', '_edd_bundled_products' );
			$bundle_download = $wpdb->get_col( $query );
			$allow_download = false;
			foreach ( $bundle_download as $bundle ) {
				$bundle_ids = maybe_unserialize( $bundle );
				$includes_both = array_intersect( array( $download_id, $item_id ), $bundle_ids );
				if ( count( $includes_both ) >= 2 ) {
					$allow_download = true;
					break;
				}
			}

			if ( $allow_download ) {
				define( 'EDD_BYPASS_ITEM_ID_CHECK', true );
			}
		}
	}
}
add_action( 'edd_get_version', 's11_allow_single_license', 1 );