Fix filter_by_rel to handle WP_Error objects

Add check for WP_Error in filter_by_rel method to prevent errors
when WebFinger lookup fails. The method now returns early if
the webfinger parameter is a WP_Error object.

Bump version to 4.0.1

Author: pfefferle

includes/class-webfinger.php

@@ -257,7 +257,7 @@ public static function generate_post_data( $webfinger, $resource_uri ) {
 	 */
 	public static function filter_by_rel( $webfinger ) {
 		// Check if WebFinger is empty or has no links.
-		if ( empty( $webfinger ) || ! isset( $webfinger['links'] ) ) {
+		if ( \is_wp_error( $webfinger ) || empty( $webfinger ) || ! isset( $webfinger['links'] ) ) {
 			return $webfinger;
 		}
 

readme.md

@@ -5,7 +5,7 @@
 - Tags: discovery, webfinger, JRD, ostatus, activitypub
 - Requires at least: 4.2
 - Tested up to: 6.9
-- Stable tag: 4.0.0
+- Stable tag: 4.0.1
 - License: MIT
 - License URI: https://opensource.org/licenses/MIT
 
@@ -91,6 +91,10 @@ This version drops classic WebFinger (XRD) support to keep the plugin lightweigh
 
 Project maintained on github at [pfefferle/wordpress-webfinger](https://github.com/pfefferle/wordpress-webfinger).
 
+### 4.0.1
+
+* Fixed: Handle WP_Error objects in `filter_by_rel` to prevent errors when WebFinger lookup fails
+
 ### 4.0.0
 
 * Added: Site Health integration to check your WebFinger setup status directly in WordPress

webfinger.php

@@ -3,7 +3,7 @@
  * Plugin Name: WebFinger
  * Plugin URI: https://github.com/pfefferle/wordpress-webfinger
  * Description: WebFinger for WordPress
- * Version: 4.0.0
+ * Version: 4.0.1
  * Author: Matthias Pfefferle
  * Author URI: https://notiz.blog/
  * License: MIT