fix: sync posts to Elasticsearch when Post Search is disabled

includes/classes/Feature/Search/Search.php

@@ -97,8 +97,6 @@ public function set_i18n_strings(): void {
 	 * @since 2.2
 	 */
 	public function setup() {
-		Indexables::factory()->activate( 'post' );
-
 		add_action( 'init', [ $this, 'search_setup' ] );
 
 		// Set up weighting sub-module

includes/classes/Features.php

@@ -383,6 +383,12 @@ public function setup_features() {
 		 */
 		do_action( 'ep_setup_features' );
 
+		/**
+		 * Activate the post indexable regardless of whether the Post Search
+		 * feature is enabled, so posts continue to sync to Elasticsearch.
+		 */
+		Indexables::factory()->activate( 'post' );
+
 		foreach ( $this->registered_features as $feature ) {
 			$feature->set_i18n_strings();
 

tests/php/indexables/TestPostSyncWithoutSearch.php

@@ -0,0 +1,87 @@
+<?php
+/**
+ * Test post sync when Post Search feature is disabled
+ *
+ * @package elasticpress
+ */
+
+namespace ElasticPressTest;
+
+use ElasticPress;
+
+/**
+ * Test post sync without search feature class
+ */
+class TestPostSyncWithoutSearch extends BaseTestCase {
+
+	/**
+	 * Setup each test.
+	 *
+	 * @since 5.4.0
+	 */
+	public function set_up() {
+		global $wpdb;
+		parent::set_up();
+		$wpdb->suppress_errors();
+
+		$admin_id = $this->factory->user->create( array( 'role' => 'administrator' ) );
+		wp_set_current_user( $admin_id );
+
+		ElasticPress\Elasticsearch::factory()->delete_all_indices();
+
+		/**
+		 * The post indexable should be activated by the plugin bootstrap
+		 * regardless of the Post Search feature state.
+		 */
+		ElasticPress\Indexables::factory()->get( 'post' )->put_mapping();
+		ElasticPress\Indexables::factory()->get( 'post' )->sync_manager->reset_sync_queue();
+
+		$this->setup_test_post_type();
+
+		// Disable Post Search and set up remaining features.
+		ElasticPress\Features::factory()->deactivate_feature( 'search' );
+		ElasticPress\Features::factory()->setup_features();
+	}
+
+	/**
+	 * Test a simple post sync with Post Search disabled
+	 *
+	 * @since 5.4.0
+	 * @group post
+	 */
+	public function testPostSyncWithSearchDisabled() {
+		add_action( 'ep_sync_on_transition', array( $this, 'action_sync_on_transition' ), 10, 0 );
+
+		$post_id = $this->ep_factory->post->create();
+
+		ElasticPress\Elasticsearch::factory()->refresh_indices();
+
+		$this->assertTrue( ! empty( $this->fired_actions['ep_sync_on_transition'] ) );
+
+		$post = ElasticPress\Indexables::factory()->get( 'post' )->get( $post_id );
+		$this->assertTrue( ! empty( $post ) );
+	}
+
+	/**
+	 * Test that WP_Query does not use Elasticsearch for post queries when Post Search is disabled.
+	 *
+	 * Activating the post indexable wires up SyncManager and QueryIntegration, but
+	 * QueryIntegration only takes over a query when the `ep_elasticpress_enabled` filter
+	 * returns true. That filter is only added by Search::search_setup(), which does not run
+	 * when the Search feature is disabled. So enabling sync here should not turn on ES query
+	 * integration for posts.
+	 *
+	 * @since 5.4.0
+	 * @group post
+	 */
+	public function testPostQueryNotIntegratedWithSearchDisabled() {
+		$this->ep_factory->post->create();
+		$this->ep_factory->post->create( array( 'post_content' => 'findme' ) );
+
+		ElasticPress\Elasticsearch::factory()->refresh_indices();
+
+		$query = new \WP_Query( array( 's' => 'findme' ) );
+
+		$this->assertTrue( empty( $query->elasticsearch_success ) );
+	}
+}