Fix: wp core is-installed returns proper exit code when tables are missing

Author: prab18hat

features/core.feature

@@ -23,6 +23,10 @@ Feature: Manage WordPress installation
 
     When I try `wp core is-installed`
     Then the return code should be 1
+    And STDERR should contain:
+      """
+      WordPress is not installed. Missing tables:
+      """
 
     When I try `wp core is-installed --network`
     Then the return code should be 1

src/Core_Command.php

@@ -393,45 +393,32 @@ function () use ( $temp ) {
 	 * @param array{network?: bool} $assoc_args Associative arguments.
 	 */
 	public function is_installed( $args, $assoc_args ) {
-		// Check if WordPress is installed by verifying required tables exist.
-		if ( ! function_exists( 'is_blog_installed' ) ) {
-			require_once ABSPATH . 'wp-includes/load.php';
-		}
-
 		if ( is_blog_installed() && ( ! Utils\get_flag_value( $assoc_args, 'network' ) || is_multisite() ) ) {
 			global $wpdb;
-			// List of required core tables (prefix will be added automatically)
-			$required_tables = [
-				'options',
-				'users',
-				'usermeta',
-				'posts',
-				'comments',
-				'commentmeta',
-				'terms',
-				'termmeta',
-				'term_taxonomy',
-				'term_relationships',
-				'links',
-				'postmeta',
-			];
+
+			// Get core tables from $wpdb
+			$tables = $wpdb->tables();
 			$missing_tables = [];
-			foreach ( $required_tables as $table ) {
+
+			// Check if all core tables exist
+			foreach ( $tables as $table ) {
 				$table_name = $wpdb->prefix . $table;
-				// Check if table exists
 				$result = $wpdb->get_var( $wpdb->prepare(
 					"SHOW TABLES LIKE %s", $table_name
 				) );
+
 				if ( $result !== $table_name ) {
 					$missing_tables[] = $table_name;
 				}
 			}
+
 			if ( ! empty( $missing_tables ) ) {
-				// Output missing tables for debugging
 				WP_CLI::error( "WordPress is not installed. Missing tables: " . implode( ', ', $missing_tables ), 1 );
 			}
+
 			WP_CLI::halt( 0 );
 		}
+
 		WP_CLI::halt( 1 );
 	}