json_encode arrays for debug output

Author: schlessera

src/DB_Command.php

@@ -1825,8 +1825,8 @@ protected function get_sql_mode_query( $assoc_args, $modes = [] ) {
 		WP_CLI::debug(
 			sprintf(
 				'SQL mode adaptation is needed: %s => %s',
-				$this->get_current_sql_modes( $assoc_args ),
-				$modes
+				json_encode( $this->get_current_sql_modes( $assoc_args ) ),
+				json_encode( $modes )
 			)
 		);