Fix: check if DB_NAME is defined before using it

Port of #3 for v2 and v3

Author: claudiosanches

src/Controllers/Version2/class-wc-rest-system-status-v2-controller.php

@@ -696,80 +696,87 @@ protected function add_db_table_prefix( $table ) {
 	public function get_database_info() {
 		global $wpdb;
 
-		$database_table_information = $wpdb->get_results(
-			$wpdb->prepare(
-				"SELECT
-				    table_name AS 'name',
-					engine AS 'engine',
-				    round( ( data_length / 1024 / 1024 ), 2 ) 'data',
-				    round( ( index_length / 1024 / 1024 ), 2 ) 'index'
-				FROM information_schema.TABLES
-				WHERE table_schema = %s
-				ORDER BY name ASC;",
-				DB_NAME
-			)
-		);
-
-		// WC Core tables to check existence of.
-		$core_tables = apply_filters(
-			'woocommerce_database_tables',
-			array(
-				'woocommerce_sessions',
-				'woocommerce_api_keys',
-				'woocommerce_attribute_taxonomies',
-				'woocommerce_downloadable_product_permissions',
-				'woocommerce_order_items',
-				'woocommerce_order_itemmeta',
-				'woocommerce_tax_rates',
-				'woocommerce_tax_rate_locations',
-				'woocommerce_shipping_zones',
-				'woocommerce_shipping_zone_locations',
-				'woocommerce_shipping_zone_methods',
-				'woocommerce_payment_tokens',
-				'woocommerce_payment_tokenmeta',
-				'woocommerce_log',
-			)
-		);
+		$tables        = array();
+		$database_size = array();
+
+		// It is not possible to get the database name from some classes that replace wpdb (e.g., HyperDB)
+		// and that is why this if condition is needed.
+		if ( defined( 'DB_NAME' ) ) {
+			$database_table_information = $wpdb->get_results(
+				$wpdb->prepare(
+					"SELECT
+					    table_name AS 'name',
+						engine AS 'engine',
+					    round( ( data_length / 1024 / 1024 ), 2 ) 'data',
+					    round( ( index_length / 1024 / 1024 ), 2 ) 'index'
+					FROM information_schema.TABLES
+					WHERE table_schema = %s
+					ORDER BY name ASC;",
+					DB_NAME
+				)
+			);
 
-		/**
-		 * Adding the prefix to the tables array, for backwards compatibility.
-		 *
-		 * If we changed the tables above to include the prefix, then any filters against that table could break.
-		 */
-		$core_tables = array_map( array( $this, 'add_db_table_prefix' ), $core_tables );
+			// WC Core tables to check existence of.
+			$core_tables = apply_filters(
+				'woocommerce_database_tables',
+				array(
+					'woocommerce_sessions',
+					'woocommerce_api_keys',
+					'woocommerce_attribute_taxonomies',
+					'woocommerce_downloadable_product_permissions',
+					'woocommerce_order_items',
+					'woocommerce_order_itemmeta',
+					'woocommerce_tax_rates',
+					'woocommerce_tax_rate_locations',
+					'woocommerce_shipping_zones',
+					'woocommerce_shipping_zone_locations',
+					'woocommerce_shipping_zone_methods',
+					'woocommerce_payment_tokens',
+					'woocommerce_payment_tokenmeta',
+					'woocommerce_log',
+				)
+			);
 
-		/**
-		 * Organize WooCommerce and non-WooCommerce tables separately for display purposes later.
-		 *
-		 * To ensure we include all WC tables, even if they do not exist, pre-populate the WC array with all the tables.
-		 */
-		$tables = array(
-			'woocommerce' => array_fill_keys( $core_tables, false ),
-			'other'       => array(),
-		);
+			/**
+			 * Adding the prefix to the tables array, for backwards compatibility.
+			 *
+			 * If we changed the tables above to include the prefix, then any filters against that table could break.
+			 */
+			$core_tables = array_map( array( $this, 'add_db_table_prefix' ), $core_tables );
+
+			/**
+			 * Organize WooCommerce and non-WooCommerce tables separately for display purposes later.
+			 *
+			 * To ensure we include all WC tables, even if they do not exist, pre-populate the WC array with all the tables.
+			 */
+			$tables = array(
+				'woocommerce' => array_fill_keys( $core_tables, false ),
+				'other'       => array(),
+			);
 
-		$database_size = array(
-			'data'  => 0,
-			'index' => 0,
-		);
+			$database_size = array(
+				'data'  => 0,
+				'index' => 0,
+			);
 
-		$site_tables_prefix = $wpdb->get_blog_prefix( get_current_blog_id() );
-		$global_tables = $wpdb->tables( 'global', true );
-		foreach ( $database_table_information as $table ) {
-			// Only include tables matching the prefix of the current site, this is to prevent displaying all tables on a MS install not relating to the current.
-			if ( is_multisite() && 0 !== strpos( $table->name, $site_tables_prefix ) && ! in_array( $table->name, $global_tables, true ) ) {
-				continue;
-			}
-			$table_type = in_array( $table->name, $core_tables ) ? 'woocommerce' : 'other';
+			$site_tables_prefix = $wpdb->get_blog_prefix( get_current_blog_id() );
+			$global_tables      = $wpdb->tables( 'global', true );
+			foreach ( $database_table_information as $table ) {
+				// Only include tables matching the prefix of the current site, this is to prevent displaying all tables on a MS install not relating to the current.
+				if ( is_multisite() && 0 !== strpos( $table->name, $site_tables_prefix ) && ! in_array( $table->name, $global_tables, true ) ) {
+					continue;
+				}
+				$table_type = in_array( $table->name, $core_tables ) ? 'woocommerce' : 'other';
 
-			$tables[ $table_type ][ $table->name ] = array(
-				'data'   => $table->data,
-				'index'  => $table->index,
-				'engine' => $table->engine,
-			);
+				$tables[ $table_type ][ $table->name ] = array(
+					'data'   => $table->data,
+					'index'  => $table->index,
+					'engine' => $table->engine,
+				);
 
-			$database_size['data']  += $table->data;
-			$database_size['index'] += $table->index;
+				$database_size['data']  += $table->data;
+				$database_size['index'] += $table->index;
+			}
 		}
 
 		// Return all database info. Described by JSON Schema.