Fixed Polylang incompatibility with MultisiteRelationship.

CHANGELOG.md

@@ -4,6 +4,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [1.28.1] - 2020-02-17
+
+### Fixed
+- Polylang incompatibility with MultisiteRelationship.
+
 ## [1.28.0] - 2020-02-07
 
 ### Added

src/Fields/MultisiteRelationship.php

@@ -68,13 +68,33 @@ public function get_ajax_query( $options = array() ) {
 
             \switch_to_blog( $blog_id );
 
+            add_filter('acf/fields/relationship/query', [ $this, 'polylang_filter' ], 100, 3 );
+
             $response = parent::get_ajax_query( $options );
 
+            remove_filter('acf/fields/relationship/query', [ $this, 'polylang_filter' ], 100 );
+
             \restore_current_blog();
 
             return $response;
         }
 
+        /**
+         * A plugin specific fix for Polylang injecting wrong language taxonomy IDs with switch_to_blog.
+         *
+         * @param array $args The arguments to filter.
+         * @param array $field The field object.
+         * @param int $post_id The post ID.
+         * @return array
+         */
+        public function polylang_filter( $args, $field, $post_id ) {
+            if ( function_exists( 'pll_current_language' ) && empty( $args['lang'] ) ) {
+                $args['lang'] = \pll_current_language();
+            }
+
+            return $args;
+        }
+
         /**
          * Get post title
          *