Delete trashed orders after `EMPTY_TRASH_DAYS` as defined by WordPress (HPOS) (#41949)

* Add a test that fails if trashed orders are never deleted under HPOS

* Delete trashed orders after `EMPTY_TRASH_DAYS` as defined by WordPress

* add the changelog file

* appease the linter

* return early if HPOS is not authorative

* attempt to precede WordPress itself (which uses priority 10) to increase the probability of orders and their posts being handled solely by us

* appease the linter

plugins/woocommerce/changelog/fix-41249

@@ -0,0 +1,4 @@
+Significance: patch
+Type: fix
+
+Delete trashed orders after `EMPTY_TRASH_DAYS` as defined by WordPress (HPOS)

plugins/woocommerce/src/Internal/DataStores/Orders/DataSynchronizer.php

@@ -80,6 +80,13 @@ class DataSynchronizer implements BatchProcessorInterface {
 	 */
 	private $error_logger;
 
+	/**
+	 * The instance of the LegacyProxy object to use.
+	 *
+	 * @var LegacyProxy
+	 */
+	private $legacy_proxy;
+
 	/**
 	 * The order cache controller.
 	 *
@@ -103,6 +110,7 @@ class DataSynchronizer implements BatchProcessorInterface {
 		self::add_action( 'woocommerce_refund_created', array( $this, 'handle_updated_order' ), 100 );
 		self::add_action( 'woocommerce_update_order', array( $this, 'handle_updated_order' ), 100 );
 		self::add_action( 'wp_scheduled_auto_draft_delete', array( $this, 'delete_auto_draft_orders' ), 9 );
+		self::add_action( 'wp_scheduled_delete', array( $this, 'delete_trashed_orders' ), 9 );
 		self::add_filter( 'updated_option', array( $this, 'process_updated_option' ), 999, 3 );
 		self::add_filter( 'added_option', array( $this, 'process_added_option' ), 999, 2 );
 		self::add_filter( 'deleted_option', array( $this, 'process_deleted_option' ), 999 );
@@ -136,6 +144,7 @@ class DataSynchronizer implements BatchProcessorInterface {
 		$this->data_store                  = $data_store;
 		$this->database_util               = $database_util;
 		$this->posts_to_cot_migrator       = $posts_to_cot_migrator;
+		$this->legacy_proxy                = $legacy_proxy;
 		$this->error_logger                = $legacy_proxy->call_function( 'wc_get_logger' );
 		$this->order_cache_controller      = $order_cache_controller;
 		$this->batch_processing_controller = $batch_processing_controller;
@@ -966,6 +975,41 @@ ORDER BY orders.id ASC
 		do_action( 'woocommerce_scheduled_auto_draft_delete' );
 	}
 
+	/**
+	 * Handles deletion of trashed orders after `EMPTY_TRASH_DAYS` as defined by WordPress.
+	 *
+	 * @since 8.5.0
+	 *
+	 * @return void
+	 */
+	private function delete_trashed_orders() {
+		if ( ! $this->custom_orders_table_is_authoritative() ) {
+			return;
+		}
+
+		$delete_timestamp = $this->legacy_proxy->call_function( 'time' ) - ( DAY_IN_SECONDS * EMPTY_TRASH_DAYS );
+		$args             = array(
+			'status'        => 'trash',
+			'limit'         => self::ORDERS_SYNC_BATCH_SIZE,
+			'date_modified' => '<' . $delete_timestamp,
+		);
+
+		$orders = wc_get_orders( $args );
+		if ( ! $orders || ! is_array( $orders ) ) {
+			return;
+		}
+
+		foreach ( $orders as $order ) {
+			if ( $order->get_status() !== 'trash' ) {
+				continue;
+			}
+			if ( $order->get_date_modified()->getTimestamp() >= $delete_timestamp ) {
+				continue;
+			}
+			$order->delete( true );
+		}
+	}
+
 	/**
 	 * Handle the 'woocommerce_feature_description_tip' filter.
 	 *

plugins/woocommerce/tests/php/src/Internal/DataStores/Orders/DataSynchronizerTests.php

@@ -25,13 +25,18 @@ class DataSynchronizerTests extends HposTestCase {
 	 */
 	public function setUp(): void {
 		parent::setUp();
+
+		$this->reset_legacy_proxy_mocks();
+		$container = wc_get_container();
+		$container->reset_all_resolved();
+
 		// Remove the Test Suite’s use of temporary tables https://wordpress.stackexchange.com/a/220308.
 		remove_filter( 'query', array( $this, '_create_temporary_tables' ) );
 		remove_filter( 'query', array( $this, '_drop_temporary_tables' ) );
 		OrderHelper::delete_order_custom_tables(); // We need this since non-temporary tables won't drop automatically.
 		OrderHelper::create_order_custom_table_if_not_exist();
 		OrderHelper::toggle_cot_feature_and_usage( false );
-		$this->sut = wc_get_container()->get( DataSynchronizer::class );
+		$this->sut = $container->get( DataSynchronizer::class );
 	}
 
 	/**
@@ -530,6 +535,53 @@ class DataSynchronizerTests extends HposTestCase {
 		$this->assertNotContains( $order1->get_id(), $orders );
 	}
 
+	/**
+	 * Test that trashed orders are deleted after the time set in `EMPTY_TRASH_DAYS`.
+	 */
+	public function test_trashed_order_deletion(): void {
+		$this->toggle_cot_authoritative( true );
+		$this->disable_cot_sync();
+
+		$order = new WC_Order();
+		$order->save();
+
+		// Ensure the placeholder post is there.
+		$placeholder = get_post( $order->get_id() );
+		$this->assertEquals( $order->get_id(), $placeholder->ID );
+
+		// Trashed orders should be deleted by the collection mechanism.
+		$order->get_data_store()->delete( $order );
+		$this->assertEquals( $order->get_status(), 'trash' );
+		$order->save();
+
+		// Run scheduled deletion.
+		do_action( 'wp_scheduled_delete' ); // phpcs:ignore WooCommerce.Commenting.CommentHooks.HookCommentWrongStyle
+
+		// Refresh order and ensure it's *not* gone.
+		$order = wc_get_order( $order->get_id() );
+		$this->assertNotNull( $order );
+
+		// Time-travel into the future so that the time required to delete a trashed order has passed.
+		$this->register_legacy_proxy_function_mocks(
+			array(
+				'time' => function() {
+					return time() + DAY_IN_SECONDS * EMPTY_TRASH_DAYS + 1;
+				},
+			)
+		);
+
+		// Run scheduled deletion.
+		do_action( 'wp_scheduled_delete' ); // phpcs:ignore WooCommerce.Commenting.CommentHooks.HookCommentWrongStyle
+
+		// Ensure the placeholder post is gone.
+		$placeholder = get_post( $order->get_id() );
+		$this->assertNull( $placeholder );
+
+		// Refresh order and ensure it's gone.
+		$order = wc_get_order( $order->get_id() );
+		$this->assertFalse( $order );
+	}
+
 	/**
 	 * @testDox When HPOS is enabled, the custom orders table is created.
 	 */