Show notice when regeneration is taking place with link to AS

includes/admin/class-wc-admin-notices.php

@@ -26,13 +26,14 @@ class WC_Admin_Notices {
 	 * @var array
 	 */
 	private static $core_notices = array(
-		'install'                 => 'install_notice',
-		'update'                  => 'update_notice',
-		'template_files'          => 'template_file_check_notice',
-		'legacy_shipping'         => 'legacy_shipping_notice',
-		'no_shipping_methods'     => 'no_shipping_methods_notice',
-		'regenerating_thumbnails' => 'regenerating_thumbnails_notice',
-		'no_secure_connection'    => 'secure_connection_notice',
+		'install'                   => 'install_notice',
+		'update'                    => 'update_notice',
+		'template_files'            => 'template_file_check_notice',
+		'legacy_shipping'           => 'legacy_shipping_notice',
+		'no_shipping_methods'       => 'no_shipping_methods_notice',
+		'regenerating_thumbnails'   => 'regenerating_thumbnails_notice',
+		'regenerating_lookup_table' => 'regenerating_lookup_table_notice',
+		'no_secure_connection'      => 'secure_connection_notice',
 	);
 
 	/**
@@ -323,6 +324,21 @@ class WC_Admin_Notices {
 		include dirname( __FILE__ ) . '/views/html-notice-secure-connection.php';
 	}
 
+	/**
+	 * Notice shown when regenerating thumbnails background process is running.
+	 *
+	 * @since 3.6.0
+	 */
+	public static function regenerating_lookup_table_notice() {
+		// See if this is still relevent.
+		if ( ! wc_update_product_lookup_tables_is_running() ) {
+			self::remove_notice( 'regenerating_lookup_table' );
+			return;
+		}
+
+		include dirname( __FILE__ ) . '/views/html-notice-regenerating-lookup-table.php';
+	}
+
 	/**
 	 * Determine if the store is running SSL.
 	 *

includes/admin/views/html-notice-regenerating-lookup-table.php

@@ -0,0 +1,27 @@
+<?php
+/**
+ * Admin View: Notice - Regenerating thumbnails.
+ *
+ * @package WooCommerce/admin
+ */
+
+defined( 'ABSPATH' ) || exit;
+
+?>
+<div id="message" class="updated woocommerce-message">
+	<a class="woocommerce-message-close notice-dismiss" href="<?php echo esc_url( admin_url( 'admin.php?page=wc-status&tab=action-scheduler&s=wc_update_product_lookup_tables&status=pending' ) ); ?>"><?php esc_html_e( 'View progress', 'woocommerce' ); ?></a>
+
+	<p>
+		<string><?php esc_html_e( 'WooCommerce is updating product data in the background. ', 'woocommerce' ); ?></strong>
+		<?php
+		echo wp_kses_post(
+			sprintf(
+				/* Translators: 1: Link, 2: link close. */
+				__( 'Some queries and reports may not show accurate results until this finishes. It will take a few minutes and this notice will disappear when complete.', 'woocommerce' ),
+				'<a href="' . esc_url( admin_url( 'admin.php?page=wc-status&tab=action-scheduler&s=wc_update_product_lookup_tables' ) ) . '">',
+				'</a>'
+			)
+		);
+		?>
+	</p>
+</div>

includes/api/v2/class-wc-rest-system-status-tools-v2-controller.php

@@ -493,10 +493,9 @@ class WC_REST_System_Status_Tools_V2_Controller extends WC_REST_Controller {
 				break;
 
 			case 'regenerate_product_lookup_tables':
-				// Clear existing data.
-				$wpdb->query( "TRUNCATE TABLE {$wpdb->wc_product_meta_lookup};" );
-				// Run generation.
-				wc_update_product_lookup_tables();
+				if ( ! wc_update_product_lookup_tables_is_running() ) {
+					wc_update_product_lookup_tables();
+				}
 				$message = __( 'Lookup tables are regenerating', 'woocommerce' );
 				break;
 			case 'reset_roles':

includes/wc-product-functions.php

@@ -1270,6 +1270,24 @@ function wc_deferred_product_sync( $product_id ) {
 	$wc_deferred_product_sync[] = $product_id;
 }
 
+/**
+ * See if the lookup table is being generated already.
+ *
+ * @since 3.6.0
+ * @return bool
+ */
+function wc_update_product_lookup_tables_is_running() {
+	$table_updates_pending = WC()->queue()->search(
+		array(
+			'status'   => 'pending',
+			'group'    => 'wc_update_product_lookup_tables',
+			'per_page' => 1,
+		)
+	);
+
+	return (bool) count( $table_updates_pending );
+}
+
 /**
  * Populate lookup table data for products.
  *
@@ -1340,6 +1358,9 @@ function wc_update_product_lookup_tables() {
 			);
 		}
 	}
+
+	// Add notice.
+	WC_Admin_Notices::add_notice( 'regenerating_lookup_table' );
 }
 
 /**