feat: automatically disable guest authors

includes/plugins/co-authors-plus/class-guest-contributor-role.php

@@ -20,6 +20,8 @@
  *
  * This role can also be assigned to users who have other roles, so they can be assigned as co-authors of a post without having the capability to edit posts.
  * This is done via a custom UI in the user profile.
+ *
+ * CAP's Guest Authors feature will be disabled by default if there are no Guest Authors in the site. If you want to force enabling it, add the NEWSPACK_ENABLE_CAP_GUEST_AUTHORS constant to your wp-config.php file.
  */
 class Guest_Contributor_Role {
 	/**
@@ -41,16 +43,13 @@ class Guest_Contributor_Role {
 	/**
 	 * Initialize hooks and filters.
 	 */
-	public static function init() {
+	public static function initialize() {
 		add_filter( 'coauthors_edit_author_cap', [ __CLASS__, 'coauthors_edit_author_cap' ] );
 		add_action( 'admin_init', [ __CLASS__, 'setup_custom_role_and_capability' ] );
 		add_action( 'template_redirect', [ __CLASS__, 'prevent_myaccount_update' ] );
 		add_action( 'newspack_before_delete_account', [ __CLASS__, 'before_delete_account' ] );
 
-		if ( defined( 'NEWSPACK_DISABLE_CAP_GUEST_AUTHORS' ) && NEWSPACK_DISABLE_CAP_GUEST_AUTHORS ) {
-			add_filter( 'coauthors_guest_authors_enabled', '__return_false' );
-			add_action( 'admin_menu', [ __CLASS__, 'guest_author_menu_replacement' ] );
-		}
+		add_action( 'init', [ __CLASS__, 'early_init' ], 5 );
 
 		// Do not allow guest authors to login.
 		\add_filter( 'wp_authenticate_user', [ __CLASS__, 'wp_authenticate_user' ], 10, 2 );
@@ -75,6 +74,47 @@ public static function init() {
 		add_action( 'wp_update_user', [ __CLASS__, 'edit_user_profile_update' ] );
 	}
 
+	/**
+	 * Runs early in the init hook to make sure it runs before Co-Authors Plus initialization.
+	 *
+	 * @return void
+	 */
+	public static function early_init() {
+		if ( defined( 'NEWSPACK_ENABLE_CAP_GUEST_AUTHORS' ) && NEWSPACK_ENABLE_CAP_GUEST_AUTHORS ) {
+			return;
+		}
+		if ( ! self::site_has_cap_guest_authors() ) {
+			add_filter( 'coauthors_guest_authors_enabled', '__return_false' );
+			add_action( 'admin_menu', [ __CLASS__, 'guest_author_menu_replacement' ] );
+		}
+	}
+
+	/**
+	 * Checks if the site has any guest authors. Will check it once in the database and store the result in an option.
+	 *
+	 * @return bool
+	 */
+	private static function site_has_cap_guest_authors() {
+		$option_name = 'newspack_check_site_has_cap_guest_authors';
+		$response    = get_option( $option_name );
+
+		// Only check in the database once.
+		if ( false === $response ) {
+			$query = new \WP_Query(
+				[
+					'post_type'      => 'guest-author',
+					'posts_per_page' => 1,
+					'post_status'    => 'any',
+					'fields'         => 'ids',
+				]
+			);
+			$response = $query->have_posts() ? 'yes' : 'no';
+			add_option( $option_name, $response, '', true );
+		}
+
+		return 'yes' === $response;
+	}
+
 	/**
 	 * Override the capability required to assign a user as a co-author.
 	 *
@@ -434,4 +474,4 @@ public static function cme_capabilities_add_user_multi_roles( $value ) {
 		return $value;
 	}
 }
-Guest_Contributor_Role::init();
+Guest_Contributor_Role::initialize();