[COT] Reintroduce the orders cache (#35014)

plugins/woocommerce/changelog/add-order_cache

@@ -0,0 +1,4 @@
+Significance: minor
+Type: add
+
+Add a cache for orders, to use when custom order tables are enabled

plugins/woocommerce/includes/abstracts/abstract-wc-order.php

@@ -10,9 +10,11 @@
  * @package     WooCommerce\Classes
  */
 
+use Automattic\WooCommerce\Caches\OrderCache;
 use Automattic\WooCommerce\Proxies\LegacyProxy;
 use Automattic\WooCommerce\Utilities\ArrayUtil;
 use Automattic\WooCommerce\Utilities\NumberUtil;
+use Automattic\WooCommerce\Utilities\OrderUtil;
 
 defined( 'ABSPATH' ) || exit;
 
@@ -203,6 +205,11 @@ abstract class WC_Abstract_Order extends WC_Abstract_Legacy_Order {
 
 			$this->save_items();
 
+			if ( OrderUtil::orders_cache_usage_is_enabled() ) {
+				$order_cache = wc_get_container()->get( OrderCache::class );
+				$order_cache->update_if_cached( $this );
+			}
+
 			/**
 			 * Trigger action after saving to the DB.
 			 *

plugins/woocommerce/includes/admin/class-wc-admin-settings.php

@@ -488,6 +488,8 @@ if ( ! class_exists( 'WC_Admin_Settings', false ) ) :
 							$visibility_class[] = 'show_options_if_checked';
 						}
 
+						$must_disable = ArrayUtil::get_value_or_default( $value, 'disabled', false );
+
 						if ( ! isset( $value['checkboxgroup'] ) || 'start' === $value['checkboxgroup'] ) {
 							$has_tooltip             = isset( $value['tooltip'] ) && '' !== $value['tooltip'];
 							$tooltip_container_class = $has_tooltip ? 'with-tooltip' : '';
@@ -515,6 +517,7 @@ if ( ! class_exists( 'WC_Admin_Settings', false ) ) :
 						?>
 							<label for="<?php echo esc_attr( $value['id'] ); ?>">
 								<input
+									<?php echo $must_disable ? 'disabled' : ''; ?>
 									name="<?php echo esc_attr( $value['field_name'] ); ?>"
 									id="<?php echo esc_attr( $value['id'] ); ?>"
 									type="checkbox"

plugins/woocommerce/includes/class-wc-cache-helper.php

@@ -5,12 +5,15 @@
  * @package WooCommerce\Classes
  */
 
+use Automattic\WooCommerce\Caching\CacheNameSpaceTrait;
+
 defined( 'ABSPATH' ) || exit;
 
 /**
  * WC_Cache_Helper.
  */
 class WC_Cache_Helper {
+	use CacheNameSpaceTrait;
 
 	/**
 	 * Transients to delete on shutdown.
@@ -114,44 +117,6 @@ class WC_Cache_Helper {
 		}
 	}
 
-	/**
-	 * Get prefix for use with wp_cache_set. Allows all cache in a group to be invalidated at once.
-	 *
-	 * @param  string $group Group of cache to get.
-	 * @return string
-	 */
-	public static function get_cache_prefix( $group ) {
-		// Get cache key - uses cache key wc_orders_cache_prefix to invalidate when needed.
-		$prefix = wp_cache_get( 'wc_' . $group . '_cache_prefix', $group );
-
-		if ( false === $prefix ) {
-			$prefix = microtime();
-			wp_cache_set( 'wc_' . $group . '_cache_prefix', $prefix, $group );
-		}
-
-		return 'wc_cache_' . $prefix . '_';
-	}
-
-	/**
-	 * Increment group cache prefix (invalidates cache).
-	 *
-	 * @param string $group Group of cache to clear.
-	 */
-	public static function incr_cache_prefix( $group ) {
-		wc_deprecated_function( 'WC_Cache_Helper::incr_cache_prefix', '3.9.0', 'WC_Cache_Helper::invalidate_cache_group' );
-		self::invalidate_cache_group( $group );
-	}
-
-	/**
-	 * Invalidate cache group.
-	 *
-	 * @param string $group Group of cache to clear.
-	 * @since 3.9.0
-	 */
-	public static function invalidate_cache_group( $group ) {
-		wp_cache_set( 'wc_' . $group . '_cache_prefix', microtime(), $group );
-	}
-
 	/**
 	 * Get a hash of the customer location.
 	 *

plugins/woocommerce/includes/class-wc-order-factory.php

@@ -8,10 +8,11 @@
  * @package WooCommerce\Classes
  */
 
-defined( 'ABSPATH' ) || exit;
+use Automattic\WooCommerce\Caches\OrderCache;
-
 use Automattic\WooCommerce\Utilities\OrderUtil;
 
+defined( 'ABSPATH' ) || exit;
+
 /**
  * Order factory class
  */
@@ -30,13 +31,26 @@ class WC_Order_Factory {
 			return false;
 		}
 
+		$use_orders_cache = OrderUtil::orders_cache_usage_is_enabled();
+		if ( $use_orders_cache ) {
+			$order_cache = wc_get_container()->get( OrderCache::class );
+			$order       = $order_cache->get( $order_id );
+			if ( ! is_null( $order ) ) {
+				return $order;
+			}
+		}
+
 		$classname = self::get_class_name_for_order_id( $order_id );
 		if ( ! $classname ) {
 			return false;
 		}
 
 		try {
-			return new $classname( $order_id );
+			$order = new $classname( $order_id );
+			if ( $use_orders_cache && $order instanceof \WC_Abstract_Legacy_Order ) {
+				$order_cache->set( $order, $order_id );
+			}
+			return $order;
 		} catch ( Exception $e ) {
 			wc_caught_exception( $e, __FUNCTION__, array( $order_id ) );
 			return false;
@@ -56,6 +70,22 @@ class WC_Order_Factory {
 		$result    = array();
 		$order_ids = array_filter( array_map( array( __CLASS__, 'get_order_id' ), $order_ids ) );
 
+		$already_cached_orders = array();
+		$use_orders_cache      = OrderUtil::orders_cache_usage_is_enabled();
+		if ( $use_orders_cache ) {
+			$uncached_order_ids = array();
+			$order_cache        = wc_get_container()->get( OrderCache::class );
+			foreach ( $order_ids as $order_id ) {
+				$cached_order = $order_cache->get( absint( $order_id ) );
+				if ( is_null( $cached_order ) ) {
+					$uncached_order_ids[] = $order_id;
+				} else {
+					$already_cached_orders[] = $cached_order;
+				}
+			}
+			$order_ids = $uncached_order_ids;
+		}
+
 		// We separate order list by class, since their datastore might be different.
 		$order_list_by_class = array();
 		$order_id_classnames = self::get_class_names_for_order_ids( $order_ids );
@@ -99,9 +129,16 @@ class WC_Order_Factory {
 		}
 
 		// restore the sort order.
-		$result = array_replace( array_flip( $order_ids ), $result );
+		$result = array_values( array_replace( array_flip( $order_ids ), $result ) );
 
-		return array_values( $result );
+		if ( $use_orders_cache ) {
+			foreach ( $result as $order ) {
+				$order_cache->set( $order );
+			}
+			return array_merge( $already_cached_orders, $result );
+		} else {
+			return $result;
+		}
 	}
 
 	/**

plugins/woocommerce/src/Caches/OrderCache.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace Automattic\WooCommerce\Caches;
+
+use Automattic\WooCommerce\Caching\ObjectCache;
+
+/**
+ * A class to cache order objects.
+ */
+class OrderCache extends ObjectCache {
+
+	/**
+	 * Get the identifier for the type of the cached objects.
+	 *
+	 * @return string
+	 */
+	public function get_object_type(): string {
+		return 'orders';
+	}
+
+	/**
+	 * Get the id of an object to be cached.
+	 *
+	 * @param array|object $object The object to be cached.
+	 * @return int|string|null The id of the object, or null if it can't be determined.
+	 */
+	protected function get_object_id( $object ) {
+		return $object->get_id();
+	}
+
+	/**
+	 * Validate an object before caching it.
+	 *
+	 * @param array|object $object The object to validate.
+	 * @return string[]|null An array of error messages, or null if the object is valid.
+	 */
+	protected function validate( $object ): ?array {
+		if ( ! $object instanceof \WC_Abstract_Order ) {
+			return array( 'The supplied order is not an instance of WC_Abstract_Order, ' . gettype( $object ) );
+		}
+
+		return null;
+	}
+}

plugins/woocommerce/src/Caches/OrderCacheController.php

@@ -0,0 +1,87 @@
+<?php
+
+namespace Automattic\WooCommerce\Caches;
+
+use Automattic\WooCommerce\Internal\Features\FeaturesController;
+use Automattic\WooCommerce\Internal\Traits\AccessiblePrivateMethods;
+use Automattic\WooCommerce\Utilities\OrderUtil;
+
+/**
+ * A class to control the usage of the orders cache.
+ */
+class OrderCacheController {
+
+	use AccessiblePrivateMethods;
+
+	/**
+	 * The orders cache to use.
+	 *
+	 * @var OrderCache
+	 */
+	private $order_cache;
+
+	/**
+	 * The orders cache to use.
+	 *
+	 * @var FeaturesController
+	 */
+	private $features_controller;
+
+	/**
+	 * The backup value of the cache usage enable status, stored while the cache is temporarily disabled.
+	 *
+	 * @var null|bool
+	 */
+	private $orders_cache_usage_backup = null;
+
+	/**
+	 * Class initialization, invoked by the DI container.
+	 *
+	 * @internal
+	 * @param OrderCache $order_cache The order cache engine to use.
+	 */
+	final public function init( OrderCache $order_cache ) {
+		$this->order_cache = $order_cache;
+	}
+
+	/**
+	 * Whether order cache usage is enabled. Currently, linked to custom orders' table usage.
+	 *
+	 * @return bool True if the order cache is enabled.
+	 */
+	public function orders_cache_usage_is_enabled(): bool {
+		return OrderUtil::custom_orders_table_usage_is_enabled();
+	}
+
+	/**
+	 * Temporarily disable the order cache if it's enabled.
+	 *
+	 * This is a purely in-memory operation: a variable is created with the value
+	 * of the current enable status for the feature, and this variable
+	 * is checked by orders_cache_usage_is_enabled. In the next request the
+	 * feature will be again enabled or not depending on how the feature is set.
+	 */
+	public function temporarily_disable_orders_cache_usage(): void {
+		if ( $this->orders_cache_usage_is_temporarly_disabled() ) {
+			return;
+		}
+
+		$this->orders_cache_usage_backup = $this->orders_cache_usage_is_enabled();
+	}
+
+	/**
+	 * Check if the order cache has been temporarily disabled.
+	 *
+	 * @return bool True if the order cache is currently temporarily disabled.
+	 */
+	public function orders_cache_usage_is_temporarly_disabled(): bool {
+		return null !== $this->orders_cache_usage_backup;
+	}
+
+	/**
+	 * Restore the order cache usage that had been temporarily disabled.
+	 */
+	public function maybe_restore_orders_cache_usage(): void {
+		$this->orders_cache_usage_backup = null;
+	}
+}

plugins/woocommerce/src/Caching/CacheEngine.php

@@ -12,9 +12,11 @@ interface CacheEngine {
 	 * Retrieves an object cached under a given key.
 	 *
 	 * @param string $key They key under which the object to retrieve is cached.
+	 * @param string $group The group under which the object is cached.
+	 *
 	 * @return array|object|null The cached object, or null if there's no object cached under the passed key.
 	 */
-	public function get_cached_object( string $key);
+	public function get_cached_object( string $key, string $group = '' );
 
 	/**
 	 * Caches an object under a given key, and with a given expiration.
@@ -22,23 +24,38 @@ interface CacheEngine {
 	 * @param string       $key The key under which the object will be cached.
 	 * @param array|object $object The object to cache.
 	 * @param int          $expiration Expiration for the cached object, in seconds.
+	 * @param string       $group The group under which the object will be cached.
+	 *
 	 * @return bool True if the object is cached successfully, false otherwise.
 	 */
-	public function cache_object( string $key, $object, int $expiration): bool;
+	public function cache_object( string $key, $object, int $expiration, string $group = '' ): bool;
 
 	/**
 	 * Removes a cached object from the cache.
 	 *
 	 * @param string $key They key under which the object is cached.
+	 * @param string $group The group under which the object is cached.
+	 *
 	 * @return bool True if the object is removed from the cache successfully, false otherwise (because the object wasn't cached or for other reason).
 	 */
-	public function delete_cached_object( string $key): bool;
+	public function delete_cached_object( string $key, string $group = '' ): bool;
 
 	/**
 	 * Checks if an object is cached under a given key.
 	 *
 	 * @param string $key The key to verify.
+	 * @param string $group The group under which the object is cached.
+	 *
 	 * @return bool True if there's an object cached under the given key, false otherwise.
 	 */
-	public function is_cached( string $key): bool;
+	public function is_cached( string $key, string $group = '' ): bool;
+
+	/**
+	 * Deletes all cached objects under a given group.
+	 *
+	 * @param string $group The group to delete.
+	 *
+	 * @return bool True if the group is deleted successfully, false otherwise.
+	 */
+	public function delete_cache_group( string $group = '' ): bool;
 }

plugins/woocommerce/src/Caching/CacheNameSpaceTrait.php

@@ -0,0 +1,66 @@
+<?php
+
+namespace Automattic\WooCommerce\Caching;
+
+/**
+ * Implements namespacing algorithm to simulate grouping and namespacing for wp_cache, memcache and other caching engines that don't support grouping natively.
+ *
+ * See the algorithm details here: https://github.com/memcached/memcached/wiki/ProgrammingTricks#namespacing.
+ *
+ * To use the namespacing algorithm in the CacheEngine class:
+ * 1. Use a group string to identify all objects of a type.
+ * 2. Before setting cache, prefix the cache key by using the `get_cache_prefix`.
+ * 3. Use `invalidate_cache_group` function to invalidate all caches in entire group at once.
+ */
+trait CacheNameSpaceTrait {
+
+	/**
+	 * Get prefix for use with wp_cache_set. Allows all cache in a group to be invalidated at once.
+	 *
+	 * @param  string $group Group of cache to get.
+	 * @return string Prefix.
+	 */
+	public static function get_cache_prefix( $group ) {
+		// Get cache key - uses cache key wc_orders_cache_prefix to invalidate when needed.
+		$prefix = wp_cache_get( 'wc_' . $group . '_cache_prefix', $group );
+
+		if ( false === $prefix ) {
+			$prefix = microtime();
+			wp_cache_set( 'wc_' . $group . '_cache_prefix', $prefix, $group );
+		}
+
+		return 'wc_cache_' . $prefix . '_';
+	}
+
+	/**
+	 * Increment group cache prefix (invalidates cache).
+	 *
+	 * @param string $group Group of cache to clear.
+	 */
+	public static function incr_cache_prefix( $group ) {
+		wc_deprecated_function( 'WC_Cache_Helper::incr_cache_prefix', '3.9.0', 'WC_Cache_Helper::invalidate_cache_group' );
+		self::invalidate_cache_group( $group );
+	}
+
+	/**
+	 * Invalidate cache group.
+	 *
+	 * @param string $group Group of cache to clear.
+	 * @since 3.9.0
+	 */
+	public static function invalidate_cache_group( $group ) {
+		return wp_cache_set( 'wc_' . $group . '_cache_prefix', microtime(), $group );
+	}
+
+	/**
+	 * Helper method to get prefixed key.
+	 *
+	 * @param  string $key   Key to prefix.
+	 * @param  string $group Group of cache to get.
+	 *
+	 * @return string Prefixed key.
+	 */
+	public static function get_prefixed_key( $key, $group ) {
+		return self::get_cache_prefix( $group ) . $key;
+	}
+}

plugins/woocommerce/src/Caching/ObjectCache.php

@@ -17,8 +17,6 @@ namespace Automattic\WooCommerce\Caching;
  */
 abstract class ObjectCache {
 
-	private const CACHE_PREFIX_OPTION_NAME = 'wp_object_cache_key_prefix_';
-
 	/**
 	 * Expiration value to be passed to 'set' to use the value of $default_expiration.
 	 */
@@ -54,24 +52,10 @@ abstract class ObjectCache {
 	/**
 	 * The cache engine to use.
 	 *
-	 * @var CacheEngine
+	 * @var ?CacheEngine
 	 */
 	private $cache_engine = null;
 
-	/**
-	 * The prefix to use for cache keys to pass to the cache engine.
-	 *
-	 * @var string
-	 */
-	private $cache_key_prefix = null;
-
-	/**
-	 * The name of the option used to store the cache prefix.
-	 *
-	 * @var string
-	 */
-	private $cache_key_prefix_option_name;
-
 	/**
 	 * Gets an identifier for the types of objects cached by this class.
 	 * This identifier will be used to compose the keys passed to the cache engine,
@@ -92,8 +76,6 @@ abstract class ObjectCache {
 		if ( empty( $this->object_type ) ) {
 			throw new CacheException( 'Class ' . get_class( $this ) . ' returns an empty value for get_object_type', $this );
 		}
-
-		$this->cache_key_prefix_option_name = self::CACHE_PREFIX_OPTION_NAME . $this->object_type;
 	}
 
 	/**
@@ -117,7 +99,7 @@ abstract class ObjectCache {
 			/**
 			 * Filters the underlying cache engine to be used by an instance of ObjectCache.
 			 *
-			 * @since 6.8.0
+			 * @since 7.4.0
 			 *
 			 * @param CacheEngine $engine The cache engine to be used by default.
 			 * @param ObjectCache $cache_instance The instance of ObjectCache that will use the cache engine.
@@ -128,49 +110,16 @@ abstract class ObjectCache {
 		return $this->cache_engine;
 	}
 
-	/**
-	 * Get the current cache prefix to use, generating one if none is in use yet.
-	 *
-	 * @return string
-	 */
-	private function get_cache_key_prefix(): string {
-		$value = $this->cache_key_prefix;
-		if ( ! $value ) {
-			$value = get_option( $this->cache_key_prefix_option_name );
-			if ( ! $value ) {
-				$value = $this->create_cache_key_prefix();
-			}
-			$this->cache_key_prefix = $value;
-		}
-		return $value;
-	}
-
-	/**
-	 * Generate a prefix for the cache keys to use, containing the object type and a random string,
-	 * and store it persistently using an option.
-	 *
-	 * @return string The generated prefix.
-	 * @throws CacheException Can't store the generated prefix.
-	 */
-	private function create_cache_key_prefix(): string {
-		$prefix_variable_part = $this->get_random_string();
-		$prefix               = "woocommerce_object_cache|{$this->object_type}|{$prefix_variable_part}|";
-		if ( ! update_option( $this->cache_key_prefix_option_name, $prefix ) ) {
-			throw new CacheException( "Can't store the key prefix option", $this );
-		}
-		return $prefix;
-	}
-
 	/**
 	 * Add an object to the cache, or update an already cached object.
 	 *
-	 * @param int|string|null $id Id of the object to be cached, if null, get_object_id will be used to get it.
 	 * @param object|array    $object The object to be cached.
+	 * @param int|string|null $id Id of the object to be cached, if null, get_object_id will be used to get it.
 	 * @param int             $expiration Expiration of the cached data in seconds from the current time, or DEFAULT_EXPIRATION to use the default value.
 	 * @return bool True on success, false on error.
 	 * @throws CacheException Invalid parameter, or null id was passed and get_object_id returns null too.
 	 */
-	public function set( $id = null, $object, int $expiration = self::DEFAULT_EXPIRATION ): bool {
+	public function set( $object, $id = null, int $expiration = self::DEFAULT_EXPIRATION ): bool {
 		if ( null === $object ) {
 			throw new CacheException( "Can't cache a null value", $this, $id );
 		}
@@ -185,6 +134,62 @@ abstract class ObjectCache {
 
 		$this->verify_expiration_value( $expiration );
 
+		$errors = $this->validate( $object );
+		if ( ! is_null( $errors ) ) {
+			try {
+				$id = $this->get_id_from_object_if_null( $object, $id );
+			} catch ( \Throwable $ex ) { // phpcs:ignore Generic.CodeAnalysis.EmptyStatement.DetectedCatch
+				// Nothing else to do, we won't be able to add any significant object id to the CacheException and that's it.
+			}
+
+			if ( count( $errors ) === 1 ) {
+				throw new CacheException( 'Object validation/serialization failed: ' . $errors[0], $this, $id, $errors );
+			} elseif ( ! empty( $errors ) ) {
+				throw new CacheException( 'Object validation/serialization failed', $this, $id, $errors );
+			}
+		}
+
+		$id = $this->get_id_from_object_if_null( $object, $id );
+
+		$this->last_cached_data = $object;
+		return $this->get_cache_engine()->cache_object(
+			$id,
+			$object,
+			self::DEFAULT_EXPIRATION === $expiration ? $this->default_expiration : $expiration,
+			$this->get_object_type()
+		);
+	}
+
+	/**
+	 * Update an object in the cache, but only if an object is already cached with the same id.
+	 *
+	 * @param object|array    $object The new object that will replace the already cached one.
+	 * @param int|string|null $id Id of the object to be cached, if null, get_object_id will be used to get it.
+	 * @param int             $expiration Expiration of the cached data in seconds from the current time, or DEFAULT_EXPIRATION to use the default value.
+	 * @return bool True on success, false on error or if no object wiith the supplied id was cached.
+	 * @throws CacheException Invalid parameter, or null id was passed and get_object_id returns null too.
+	 */
+	public function update_if_cached( $object, $id = null, int $expiration = self::DEFAULT_EXPIRATION ): bool {
+		$id = $this->get_id_from_object_if_null( $object, $id );
+
+		if ( ! $this->is_cached( $id ) ) {
+			return false;
+		}
+
+		return $this->set( $object, $id, $expiration );
+	}
+
+	/**
+	 * Get the id from an object if the id itself is null.
+	 *
+	 * @param object|array    $object The object to get the id from.
+	 * @param int|string|null $id An object id or null.
+	 *
+	 * @return int|string|null Passed $id if it wasn't null, otherwise id obtained from $object using get_object_id.
+	 *
+	 * @throws CacheException Passed $id is null and get_object_id returned null too.
+	 */
+	private function get_id_from_object_if_null( $object, $id ) {
 		if ( null === $id ) {
 			$id = $this->get_object_id( $object );
 			if ( null === $id ) {
@@ -192,28 +197,7 @@ abstract class ObjectCache {
 			}
 		}
 
-		$errors = $this->validate( $object );
+		return $id;
-		if ( null !== $errors && 1 === count( $errors ) ) {
-			throw new CacheException( 'Object validation/serialization failed: ' . $errors[0], $this, $id, $errors );
-		} elseif ( ! empty( $errors ) ) {
-			throw new CacheException( 'Object validation/serialization failed', $this, $id, $errors );
-		}
-
-		$data = $this->serialize( $object );
-
-		/**
-		 * Filters the serialized object that will be passed by an instance of ObjectCache to its cache engine to be cached.
-		 *
-		 * @since 6.8.0
-		 *
-		 * @param array $data The already serialized object data.
-		 * @param array|object $object The object before serialization.
-		 * @returns array The actual serialized object data that will be passed to the cache engine.
-		 */
-		$data = apply_filters( "woocommerce_after_serializing_{$this->object_type}_for_caching", $data, $object, $id );
-
-		$this->last_cached_data = $data;
-		return $this->get_cache_engine()->cache_object( $this->get_cache_key_prefix() . $id, $data, self::DEFAULT_EXPIRATION === $expiration ? $this->default_expiration : $expiration );
 	}
 
 	/**
@@ -249,34 +233,21 @@ abstract class ObjectCache {
 
 		$this->verify_expiration_value( $expiration );
 
-		$data = $this->get_cache_engine()->get_cached_object( $this->get_cache_key_prefix() . $id );
+		$data = $this->get_cache_engine()->get_cached_object( $id, $this->get_object_type() );
 		if ( null === $data ) {
+			$object = null;
 			if ( $get_from_datastore_callback ) {
 				$object = $get_from_datastore_callback( $id );
-			} else {
-				$object = $this->get_from_datastore( $id );
 			}
 
 			if ( null === $object ) {
 				return null;
 			}
-
+			$this->set( $object, $id, $expiration );
-			$this->set( $id, $object, $expiration );
 			$data = $this->last_cached_data;
 		}
 
-		$object = $this->deserialize( $data );
+		return $data;
-
-		/**
-		 * Filters the deserialized object that is retrieved from the cache engine of an instance of ObjectCache and will be returned by 'get'.
-		 *
-		 * @since 6.8.0
-		 *
-		 * @param array|object $object The object after being deserialized.
-		 * @param array $data The serialized object data that was retrieved from the cache engine.
-		 * @returns array|object The actual deserialized object data that will be returned by 'get'.
-		 */
-		return apply_filters( "woocommerce_after_deserializing_{$this->object_type}_from_cache", $object, $data, $id );
 	}
 
 	/**
@@ -286,41 +257,16 @@ abstract class ObjectCache {
 	 * @return bool True if the object is removed from the cache successfully, false otherwise (because the object wasn't cached or for other reason).
 	 */
 	public function remove( $id ): bool {
-		$result = $this->get_cache_engine()->delete_cached_object( $this->get_cache_key_prefix() . $id );
+		return $this->get_cache_engine()->delete_cached_object( $id, $this->get_object_type() );
-
-		/**
-		 * Action triggered by an instance of ObjectCache after an object is (attempted to be) removed from the cache.
-		 *
-		 * @since 6.8.0
-		 *
-		 * @param int|string $id The id of the object being removed.
-		 * @param bool $result True if the object removal succeeded, false otherwise.
-		 */
-		do_action( "woocommerce_after_removing_{$this->object_type}_from_cache", $id, $result );
-
-		return $result;
 	}
 
 	/**
 	 * Remove all the objects from the cache.
-	 * This is done by forcing the generation of a new cache key prefix
-	 * and leaving the old cached objects to expire.
 	 *
-	 * @return void
+	 * @return bool True on success, false on error.
 	 */
-	public function flush(): void {
+	public function flush(): bool {
-		delete_option( $this->cache_key_prefix_option_name );
+		return $this->get_cache_engine()->delete_cache_group( $this->get_object_type() );
-		$this->cache_key_prefix = null;
-
-		/**
-		 * Action triggered by an instance of ObjectCache after it flushes all the cached objects.
-		 *
-		 * @since 6.8.0
-		 *
-		 * @param ObjectCache $cache_instance The instance of ObjectCache whose 'flush` method has been called.
-		 * @param CacheEngine $engine The cache engine in use.
-		 */
-		do_action( "woocommerce_after_flushing_{$this->object_type}_cache", $this, $this->get_cache_engine() );
 	}
 
 	/**
@@ -330,7 +276,7 @@ abstract class ObjectCache {
 	 * @return bool True if there's a cached object with the specified id.
 	 */
 	public function is_cached( $id ): bool {
-		return $this->get_cache_engine()->is_cached( $this->get_cache_key_prefix() . $id );
+		return $this->get_cache_engine()->is_cached( $id, $this->get_object_type() );
 	}
 
 	/**
@@ -340,9 +286,7 @@ abstract class ObjectCache {
 	 * @param array|object $object The object to get the id for.
 	 * @return int|string|null
 	 */
-	protected function get_object_id( $object ) {
+	abstract protected function get_object_id( $object );
-		return null;
-	}
 
 	/**
 	 * Validate an object before it's cached.
@@ -350,42 +294,7 @@ abstract class ObjectCache {
 	 * @param array|object $object Object to validate.
 	 * @return array|null An array with validation error messages, null or an empty array if there are no errors.
 	 */
-	protected function validate( $object ): ?array {
+	abstract protected function validate( $object ): ?array;
-		return null;
-	}
-
-	/**
-	 * Convert an object to a serialized form suitable for caching.
-	 * If a class overrides this method it should override 'deserialize' as well.
-	 *
-	 * @param array|object $object The object to serialize.
-	 * @return array The serialized object.
-	 */
-	protected function serialize( $object ): array {
-		return array( 'data' => $object );
-	}
-
-	/**
-	 * Deserializes a set of object data after having been retrieved from the cache.
-	 * If a class overrides this method it should override 'serialize' as well.
-	 *
-	 * @param array $serialized Serialized object data as it was returned by 'validate_and_serialize'.
-	 * @return object|array Deserialized object, ready to be returned by 'get'.
-	 */
-	protected function deserialize( array $serialized ) {
-		return $serialized['data'];
-	}
-
-	/**
-	 * Get an object from an authoritative data store.
-	 * This is used by 'get' if the object isn't cached and no custom object retrieval callback is suupplied.
-	 *
-	 * @param int|string $id The id of the object to get.
-	 * @return array|object|null The retrieved object, or null if it's not possible to retrieve an object by the given id.
-	 */
-	protected function get_from_datastore( $id ) {
-		return null;
-	}
 
 	/**
 	 * Get the instance of the cache engine to use.
@@ -393,7 +302,7 @@ abstract class ObjectCache {
 	 * @return CacheEngine
 	 */
 	protected function get_cache_engine_instance(): CacheEngine {
-		return wc_get_container()->get( WpCacheEngine::class );
+		return wc_get_container()->get( WPCacheEngine::class );
 	}
 
 	/**

plugins/woocommerce/src/Caching/WPCacheEngine.php

@@ -0,0 +1,76 @@
+<?php
+
+namespace Automattic\WooCommerce\Caching;
+
+/**
+ * Implementation of CacheEngine that uses the built-in WordPress cache.
+ */
+class WPCacheEngine implements CacheEngine {
+	use CacheNameSpaceTrait;
+
+	/**
+	 * Retrieves an object cached under a given key.
+	 *
+	 * @param string $key They key under which the object to retrieve is cached.
+	 * @param string $group The group under which the object is cached.
+	 *
+	 * @return array|object|null The cached object, or null if there's no object cached under the passed key.
+	 */
+	public function get_cached_object( string $key, string $group = '' ) {
+		$prefixed_key = self::get_prefixed_key( $key, $group );
+		$value        = wp_cache_get( $prefixed_key, $group );
+		return false === $value ? null : $value;
+	}
+
+	/**
+	 * Caches an object under a given key, and with a given expiration.
+	 *
+	 * @param string       $key The key under which the object will be cached.
+	 * @param array|object $object The object to cache.
+	 * @param int          $expiration Expiration for the cached object, in seconds.
+	 * @param string       $group The group under which the object will be cached.
+	 *
+	 * @return bool True if the object is cached successfully, false otherwise.
+	 */
+	public function cache_object( string $key, $object, int $expiration, string $group = '' ): bool {
+		$prefixed_key = self::get_prefixed_key( $key, $group );
+		return wp_cache_set( $prefixed_key, $object, $group, $expiration );
+	}
+
+	/**
+	 * Removes a cached object from the cache.
+	 *
+	 * @param string $key They key under which the object is cached.
+	 * @param string $group The group under which the object is cached.
+	 *
+	 * @return bool True if the object is removed from the cache successfully, false otherwise (because the object wasn't cached or for other reason).
+	 */
+	public function delete_cached_object( string $key, string $group = '' ): bool {
+		$prefixed_key = self::get_prefixed_key( $key, $group );
+		return wp_cache_delete( $prefixed_key, $group );
+	}
+
+	/**
+	 * Checks if an object is cached under a given key.
+	 *
+	 * @param string $key The key to verify.
+	 * @param string $group The group under which the object is cached.
+	 *
+	 * @return bool True if there's an object cached under the given key, false otherwise.
+	 */
+	public function is_cached( string $key, string $group = '' ): bool {
+		$prefixed_key = self::get_prefixed_key( $key, $group );
+		return false !== wp_cache_get( $prefixed_key, $group );
+	}
+
+	/**
+	 * Deletes all cached objects under a given group.
+	 *
+	 * @param string $group The group to delete.
+	 *
+	 * @return bool True if the group is deleted successfully, false otherwise.
+	 */
+	public function delete_cache_group( string $group = '' ): bool {
+		return self::invalidate_cache_group( $group );
+	}
+}

plugins/woocommerce/src/Caching/WpCacheEngine.php

@@ -1,32 +0,0 @@
-<?php
-
-namespace Automattic\WooCommerce\Caching;
-
-/**
- * Implementation of CacheEngine that uses the built-in WordPress cache.
- */
-class WpCacheEngine implements CacheEngine {
-
-	public const CACHE_GROUP_NAME = 'wc-object-cache';
-
-	// phpcs:disable Squiz.Commenting.FunctionComment.Missing
-
-	public function get_cached_object( string $key ) {
-		$value = wp_cache_get( $key, self::CACHE_GROUP_NAME );
-		return false === $value ? null : $value;
-	}
-
-	public function cache_object( string $key, $object, int $expiration ): bool {
-		return wp_cache_set( $key, $object, self::CACHE_GROUP_NAME, $expiration );
-	}
-
-	public function delete_cached_object( string $key ): bool {
-		return wp_cache_delete( $key, self::CACHE_GROUP_NAME );
-	}
-
-	public function is_cached( string $key ): bool {
-		return false !== wp_cache_get( $key, self::CACHE_GROUP_NAME );
-	}
-
-	// phpcs:enable Squiz.Commenting.FunctionComment.Missing
-}

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

@@ -5,9 +5,12 @@
 
 namespace Automattic\WooCommerce\Internal\DataStores\Orders;
 
+use Automattic\WooCommerce\Caches\OrderCache;
+use Automattic\WooCommerce\Caches\OrderCacheController;
 use Automattic\WooCommerce\Internal\BatchProcessing\BatchProcessingController;
 use Automattic\WooCommerce\Internal\Features\FeaturesController;
 use Automattic\WooCommerce\Internal\Traits\AccessiblePrivateMethods;
+use Automattic\WooCommerce\Utilities\OrderUtil;
 
 defined( 'ABSPATH' ) || exit;
 
@@ -81,6 +84,20 @@ class CustomOrdersTableController {
 	 */
 	private $features_controller;
 
+	/**
+	 * The orders cache object to use.
+	 *
+	 * @var OrderCache
+	 */
+	private $order_cache;
+
+	/**
+	 * The orders cache controller object to use.
+	 *
+	 * @var OrderCacheController
+	 */
+	private $order_cache_controller;
+
 	/**
 	 * Class constructor.
 	 */
@@ -114,18 +131,24 @@ class CustomOrdersTableController {
 	 * @param OrdersTableRefundDataStore $refund_data_store The refund data store to use.
 	 * @param BatchProcessingController  $batch_processing_controller The batch processing controller to use.
 	 * @param FeaturesController         $features_controller The features controller instance to use.
+	 * @param OrderCache                 $order_cache The order cache engine to use.
+	 * @param OrderCacheController       $order_cache_controller The order cache controller to use.
 	 */
 	final public function init(
 		OrdersTableDataStore $data_store,
 		DataSynchronizer $data_synchronizer,
 		OrdersTableRefundDataStore $refund_data_store,
 		BatchProcessingController $batch_processing_controller,
-		FeaturesController $features_controller ) {
+		FeaturesController $features_controller,
+		OrderCache $order_cache,
+		OrderCacheController $order_cache_controller ) {
 		$this->data_store                  = $data_store;
 		$this->data_synchronizer           = $data_synchronizer;
 		$this->batch_processing_controller = $batch_processing_controller;
 		$this->refund_data_store           = $refund_data_store;
 		$this->features_controller         = $features_controller;
+		$this->order_cache                 = $order_cache;
+		$this->order_cache_controller      = $order_cache_controller;
 	}
 
 	/**
@@ -462,12 +485,19 @@ class CustomOrdersTableController {
 	 * @throws \Exception Attempt to change the authoritative orders table while orders sync is pending.
 	 */
 	private function process_pre_update_option( $value, $option, $old_value ) {
+		if ( DataSynchronizer::ORDERS_DATA_SYNC_ENABLED_OPTION === $option && $value !== $old_value ) {
+			$this->order_cache->flush();
+			return $value;
+		}
+
 		if ( self::CUSTOM_ORDERS_TABLE_USAGE_ENABLED_OPTION !== $option || $value === $old_value || false === $old_value ) {
 			return $value;
 		}
 
+		$this->order_cache->flush();
+
 		/**
-		 * Commenting out for better testability.
+		 * Re-enable the following code once the COT to posts table sync is implemented (it's currently commented out to ease testing).
 		$sync_is_pending = 0 !== $this->data_synchronizer->get_current_orders_pending_sync_count();
 		if ( $sync_is_pending ) {
 			throw new \Exception( "The authoritative table for orders storage can't be changed while there are orders out of sync" );
@@ -575,4 +605,6 @@ class CustomOrdersTableController {
 			)
 		);
 	}
+
+
 }

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

@@ -5,6 +5,8 @@
 
 namespace Automattic\WooCommerce\Internal\DataStores\Orders;
 
+use Automattic\WooCommerce\Caches\OrderCache;
+use Automattic\WooCommerce\Caches\OrderCacheController;
 use Automattic\WooCommerce\Database\Migrations\CustomOrderTable\PostsToOrdersMigrationController;
 use Automattic\WooCommerce\Internal\BatchProcessing\BatchProcessorInterface;
 use Automattic\WooCommerce\Internal\Features\FeaturesController;
@@ -63,6 +65,13 @@ class DataSynchronizer implements BatchProcessorInterface {
 	 */
 	private $error_logger;
 
+	/**
+	 * The order cache controller.
+	 *
+	 * @var OrderCacheController
+	 */
+	private $order_cache_controller;
+
 	/**
 	 * Class constructor.
 	 */
@@ -80,13 +89,21 @@ class DataSynchronizer implements BatchProcessorInterface {
 	 * @param DatabaseUtil                     $database_util The database util class to use.
 	 * @param PostsToOrdersMigrationController $posts_to_cot_migrator The posts to COT migration class to use.
 	 * @param LegacyProxy                      $legacy_proxy The legacy proxy instance to use.
+	 * @param OrderCacheController             $order_cache_controller The order cache controller instance to use.
 	 * @internal
 	 */
-	final public function init( OrdersTableDataStore $data_store, DatabaseUtil $database_util, PostsToOrdersMigrationController $posts_to_cot_migrator, LegacyProxy $legacy_proxy ) {
+	final public function init(
+		OrdersTableDataStore $data_store,
+		DatabaseUtil $database_util,
+		PostsToOrdersMigrationController $posts_to_cot_migrator,
+		LegacyProxy $legacy_proxy,
+		OrderCacheController $order_cache_controller
+	) {
 		$this->data_store             = $data_store;
 		$this->database_util          = $database_util;
 		$this->posts_to_cot_migrator  = $posts_to_cot_migrator;
 		$this->error_logger           = $legacy_proxy->call_function( 'wc_get_logger' );
+		$this->order_cache_controller = $order_cache_controller;
 	}
 
 	/**
@@ -329,6 +346,8 @@ WHERE
 	 * @param array $batch Batch details.
 	 */
 	public function process_batch( array $batch ) : void {
+		$this->order_cache_controller->temporarily_disable_orders_cache_usage();
+
 		if ( $this->custom_orders_table_is_authoritative() ) {
 			foreach ( $batch as $id ) {
 				$order = wc_get_order( $id );
@@ -344,6 +363,7 @@ WHERE
 		}
 		if ( 0 === $this->get_total_pending_count() ) {
 			$this->cleanup_synchronization_state();
+			$this->order_cache_controller->maybe_restore_orders_cache_usage();
 		}
 	}
 

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

@@ -6,6 +6,7 @@
 namespace Automattic\WooCommerce\Internal\DataStores\Orders;
 
 use Automattic\Jetpack\Constants;
+use Automattic\WooCommerce\Caches\OrderCache;
 use Automattic\WooCommerce\Internal\Utilities\DatabaseUtil;
 use Automattic\WooCommerce\Proxies\LegacyProxy;
 use Automattic\WooCommerce\Utilities\ArrayUtil;
@@ -1974,6 +1975,7 @@ FROM $order_meta_table
 	 */
 	public function delete_order_data_from_custom_order_tables( $order_id ) {
 		global $wpdb;
+		$order_cache = wc_get_container()->get( OrderCache::class );
 
 		// Delete COT-specific data.
 		foreach ( $this->get_all_table_names() as $table ) {
@@ -1984,6 +1986,7 @@ FROM $order_meta_table
 					: array( 'order_id' => $order_id ),
 				array( '%d' )
 			);
+			$order_cache->remove( $order_id );
 		}
 	}
 

plugins/woocommerce/src/Internal/DependencyManagement/ServiceProviders/COTMigrationServiceProvider.php

@@ -7,7 +7,6 @@ namespace Automattic\WooCommerce\Internal\DependencyManagement\ServiceProviders;
 
 use Automattic\WooCommerce\DataBase\Migrations\CustomOrderTable\CLIRunner;
 use Automattic\WooCommerce\Database\Migrations\CustomOrderTable\PostsToOrdersMigrationController;
-use Automattic\WooCommerce\Internal\DataStores\Orders\DataSynchronizer;
 use Automattic\WooCommerce\Internal\DependencyManagement\AbstractServiceProvider;
 
 /**
@@ -25,7 +24,6 @@ class COTMigrationServiceProvider extends AbstractServiceProvider {
 	protected $provides = array(
 		PostsToOrdersMigrationController::class,
 		CLIRunner::class,
-		DataSynchronizer::class,
 	);
 
 	/**
@@ -37,5 +35,6 @@ class COTMigrationServiceProvider extends AbstractServiceProvider {
 	 */
 	public function register() {
 		$this->share( PostsToOrdersMigrationController::class );
+		$this->share( CLIRunner::class );
 	}
 }

plugins/woocommerce/src/Internal/DependencyManagement/ServiceProviders/ObjectCacheServiceProvider.php

@@ -2,7 +2,7 @@
 
 namespace Automattic\WooCommerce\Internal\DependencyManagement\ServiceProviders;
 
-use Automattic\WooCommerce\Caching\WpCacheEngine;
+use Automattic\WooCommerce\Caching\WPCacheEngine;
 use Automattic\WooCommerce\Internal\DependencyManagement\AbstractServiceProvider;
 
 /**
@@ -16,13 +16,13 @@ class ObjectCacheServiceProvider extends AbstractServiceProvider {
 	 * @var array
 	 */
 	protected $provides = array(
-		WpCacheEngine::class,
+		WPCacheEngine::class,
 	);
 
 	/**
 	 * Register the classes.
 	 */
 	public function register() {
-		$this->share( WpCacheEngine::class );
+		$this->share( WPCacheEngine::class );
 	}
 }

plugins/woocommerce/src/Internal/DependencyManagement/ServiceProviders/OrdersDataStoreServiceProvider.php

@@ -6,6 +6,9 @@
 namespace Automattic\WooCommerce\Internal\DependencyManagement\ServiceProviders;
 
 use Automattic\Jetpack\Constants;
+use Automattic\WooCommerce\Caches\OrderCache;
+use Automattic\WooCommerce\Caches\OrderCacheController;
+use Automattic\WooCommerce\Caching\TransientsEngine;
 use Automattic\WooCommerce\DataBase\Migrations\CustomOrderTable\CLIRunner;
 use Automattic\WooCommerce\Database\Migrations\CustomOrderTable\PostsToOrdersMigrationController;
 use Automattic\WooCommerce\Internal\BatchProcessing\BatchProcessingController;
@@ -36,6 +39,8 @@ class OrdersDataStoreServiceProvider extends AbstractServiceProvider {
 		CLIRunner::class,
 		OrdersTableDataStoreMeta::class,
 		OrdersTableRefundDataStore::class,
+		OrderCache::class,
+		OrderCacheController::class,
 	);
 
 	/**
@@ -45,7 +50,15 @@ class OrdersDataStoreServiceProvider extends AbstractServiceProvider {
 		$this->share( OrdersTableDataStoreMeta::class );
 
 		$this->share( OrdersTableDataStore::class )->addArguments( array( OrdersTableDataStoreMeta::class, DatabaseUtil::class, LegacyProxy::class ) );
-		$this->share( DataSynchronizer::class )->addArguments( array( OrdersTableDataStore::class, DatabaseUtil::class, PostsToOrdersMigrationController::class, LegacyProxy::class ) );
+		$this->share( DataSynchronizer::class )->addArguments(
+			array(
+				OrdersTableDataStore::class,
+				DatabaseUtil::class,
+				PostsToOrdersMigrationController::class,
+				LegacyProxy::class,
+				OrderCacheController::class,
+			)
+		);
 		$this->share( OrdersTableRefundDataStore::class )->addArguments( array( OrdersTableDataStoreMeta::class, DatabaseUtil::class, LegacyProxy::class ) );
 		$this->share( CustomOrdersTableController::class )->addArguments(
 			array(
@@ -54,9 +67,12 @@ class OrdersDataStoreServiceProvider extends AbstractServiceProvider {
 				OrdersTableRefundDataStore::class,
 				BatchProcessingController::class,
 				FeaturesController::class,
+				OrderCache::class,
+				OrderCacheController::class,
 			)
 		);
-
+		$this->share( OrderCache::class );
+		$this->share( OrderCacheController::class )->addArgument( OrderCache::class );
 		if ( Constants::is_defined( 'WP_CLI' ) && WP_CLI ) {
 			$this->share( CLIRunner::class )->addArguments( array( CustomOrdersTableController::class, DataSynchronizer::class, PostsToOrdersMigrationController::class ) );
 		}

plugins/woocommerce/src/Utilities/OrderUtil.php

@@ -5,8 +5,10 @@
 
 namespace Automattic\WooCommerce\Utilities;
 
+use Automattic\WooCommerce\Caches\OrderCacheController;
 use Automattic\WooCommerce\Internal\Admin\Orders\PageController;
 use Automattic\WooCommerce\Internal\DataStores\Orders\CustomOrdersTableController;
+use Automattic\WooCommerce\Internal\Features\FeaturesController;
 use Automattic\WooCommerce\Internal\Utilities\COTMigrationUtil;
 use WC_Order;
 use WP_Post;
@@ -35,6 +37,15 @@ final class OrderUtil {
 		return wc_get_container()->get( CustomOrdersTableController::class )->custom_orders_table_usage_is_enabled();
 	}
 
+	/**
+	 * Helper function to get whether the orders cache should be used or not.
+	 *
+	 * @return bool True if the orders cache should be used, false otherwise.
+	 */
+	public static function orders_cache_usage_is_enabled() : bool {
+		return wc_get_container()->get( OrderCacheController::class )->orders_cache_usage_is_enabled();
+	}
+
 	/**
 	 * Checks if posts and order custom table sync is enabled and there are no pending orders.
 	 *

plugins/woocommerce/tests/php/includes/rest-api/Controllers/Version3/class-wc-rest-orders-controller-tests.php

@@ -230,8 +230,9 @@ class WC_REST_Orders_Controller_Tests extends WC_REST_Unit_Test_Case {
 		$order = new \WC_Order();
 		$order->set_status( 'completed' );
 		$order->save();
+		$order_id = $order->get_id();
 
-		$request  = new \WP_REST_Request( 'DELETE', '/wc/v3/orders/' . $order->get_id() );
+		$request  = new \WP_REST_Request( 'DELETE', '/wc/v3/orders/' . $order_id );
 		$response = $this->server->dispatch( $request );
 
 		$this->assertEquals( 200, $response->get_status() );
@@ -239,13 +240,13 @@ class WC_REST_Orders_Controller_Tests extends WC_REST_Unit_Test_Case {
 		// Check that the response includes order data from the order (before deletion).
 		$data = $response->get_data();
 		$this->assertArrayHasKey( 'id', $data );
-		$this->assertEquals( $data['id'], $order->get_id() );
+		$this->assertEquals( $data['id'], $order_id );
 		$this->assertEquals( 'completed', $data['status'] );
 
 		wp_cache_flush();
 
 		// Check the order was actually deleted.
-		$order = wc_get_order( $order->get_id() );
+		$order = wc_get_order( $order_id );
 		$this->assertEquals( 'trash', $order->get_status( 'edit' ) );
 	}
 

plugins/woocommerce/tests/php/src/Caching/CacheExceptionTest.php

@@ -26,6 +26,15 @@ class CacheExceptionTest extends \WC_Unit_Test_Case {
 			public function get_object_type(): string {
 				return 'the_type';
 			}
+
+			protected function get_object_id( $object ) {
+			}
+
+			protected function validate( $object ): ?array {
+			}
+
+			protected function get_from_datastore( $id ) {
+			}
 		};
 		// phpcs:enable Squiz.Commenting
 	}

plugins/woocommerce/tests/php/src/Caching/InMemoryObjectCacheEngine.php

@@ -1,63 +0,0 @@
-<?php
-
-namespace Automattic\WooCommerce\Tests\Caching;
-
-use Automattic\WooCommerce\Caching\CacheEngine;
-use Automattic\WooCommerce\Utilities\ArrayUtil;
-
-/**
- * An implementation of CacheEngine that simply stores cached objects in an array.
- */
-class InMemoryObjectCacheEngine implements CacheEngine {
-
-	/**
-	 * The cached objects.
-	 *
-	 * @var array
-	 */
-	public $cache = array();
-
-	/**
-	 * Whether calls to 'cache_object' will succeed or not.
-	 *
-	 * @var bool
-	 */
-	public $caching_succeeds = true;
-
-	/**
-	 * Value of the expiration time that was passed to 'cache_object' the last time it was called.
-	 *
-	 * @var int
-	 */
-	public $last_expiration;
-
-	// phpcs:disable Squiz.Commenting
-
-	public function get_cached_object( string $key ) {
-		return ArrayUtil::get_value_or_default( $this->cache, $key, null );
-	}
-
-	public function cache_object( string $key, $object, int $expiration ): bool {
-		if ( ! $this->caching_succeeds ) {
-			return false;
-		}
-		$this->cache[ $key ]   = $object;
-		$this->last_expiration = $expiration;
-		return true;
-	}
-
-	public function delete_cached_object( string $key ): bool {
-		if ( array_key_exists( $key, $this->cache ) ) {
-			unset( $this->cache[ $key ] );
-			return true;
-		}
-
-		return false;
-	}
-
-	public function is_cached( $key ): bool {
-		return array_key_exists( $key, $this->cache );
-	}
-
-	// phpcs:enable Squiz.Commenting
-}

plugins/woocommerce/tests/php/src/Caching/InvalidObjectCacheClass.php

@@ -11,10 +11,18 @@ class InvalidObjectCacheClass extends ObjectCache {
 
 
 	// phpcs:disable Squiz.Commenting
-
 	public function get_object_type(): string {
 		return '';
 	}
 
+	protected function get_object_id( $object ) {
+	}
+
+	protected function validate( $object ): ?array {
+	}
+
+	protected function get_from_datastore( $id ) {
+	}
 	// phpcs:enable Squiz.Commenting
+
 }

plugins/woocommerce/tests/php/src/Caching/ObjectCacheTest.php

@@ -5,7 +5,7 @@ namespace Automattic\WooCommerce\Tests\Caching;
 use Automattic\WooCommerce\Caching\CacheException;
 use Automattic\WooCommerce\Caching\ObjectCache;
 use Automattic\WooCommerce\Caching\CacheEngine;
-use Automattic\WooCommerce\Caching\WpCacheEngine;
+use Automattic\WooCommerce\Caching\WPCacheEngine;
 
 /**
  * Tests for the ObjectCache class.
@@ -19,23 +19,10 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 	 */
 	private $sut;
 
-	/**
-	 * The cache engine to use.
-	 *
-	 * @var CacheEngine
-	 */
-	private $cache_engine;
-
 	/**
 	 * Runs before each test.
 	 */
 	public function setUp(): void {
-		$cache_engine       = new InMemoryObjectCacheEngine();
-		$this->cache_engine = $cache_engine;
-
-		$container = wc_get_container();
-		$container->replace( WpCacheEngine::class, $cache_engine );
-		$this->reset_container_resolutions();
 
 		// phpcs:disable Squiz.Commenting
 
@@ -50,9 +37,22 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 				$this->random_string_index++;
 				return 'random_' . $this->random_string_index;
 			}
-		};
 
+			protected function get_object_id( $object ) {
+				return null;
+			}
+
+			protected function validate( $object ): ?array {
+				return null;
+			}
+
+			protected function get_from_datastore( $id ) {
+				return null;
+			}
+		};
 		// phpcs:enable Squiz.Commenting
+
+		$this->sut->flush();
 	}
 
 	/**
@@ -94,7 +94,7 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 		$this->expectException( CacheException::class );
 		$this->expectExceptionMessage( "Can't cache a null value" );
 
-		$this->sut->set( 'the_id', null );
+		$this->sut->set( null );
 	}
 
 	/**
@@ -104,7 +104,7 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 		$this->expectException( CacheException::class );
 		$this->expectExceptionMessage( "Can't cache a non-object, non-array value" );
 
-		$this->sut->set( 'the_id', 1234 );
+		$this->sut->set( 1234 );
 	}
 
 	/**
@@ -114,7 +114,7 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 		$this->expectException( CacheException::class );
 		$this->expectExceptionMessage( "Object id must be an int, a string, or null for 'set'" );
 
-		$this->sut->set( array( 1, 2 ), array( 'foo' ) );
+		$this->sut->set( array( 'foo' ), array( 1, 2 ) );
 	}
 
 	/**
@@ -130,7 +130,7 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 		$this->expectException( CacheException::class );
 		$this->expectExceptionMessage( 'Invalid expiration value, must be ObjectCache::DEFAULT_EXPIRATION or a value between 1 and ObjectCache::MAX_EXPIRATION' );
 
-		$this->sut->set( 'the_id', array( 'foo' ), $expiration );
+		$this->sut->set( array( 'foo' ), 'the_id', $expiration );
 	}
 
 	/**
@@ -139,7 +139,7 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 	public function try_set_when_cache_engine_fails() {
 		$this->cache_engine->caching_succeeds = false;
 
-		$result = $this->sut->set( 'the_id', array( 'foo' ) );
+		$result = $this->sut->set( array( 'foo' ), 'the_id' );
 		$this->assertFalse( $result );
 	}
 
@@ -148,16 +148,14 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 	 */
 	public function test_set_new_object_with_id_caches_with_expected_key() {
 		$object = array( 'foo' );
-		$result = $this->sut->set( 'the_id', $object );
+		$result = $this->sut->set( $object, 'the_id' );
 
 		$this->assertTrue( $result );
 
-		$expected_prefix = 'woocommerce_object_cache|the_type|random_1|';
+		$expected_prefix = \WC_Cache_Helper::get_cache_prefix( 'the_type' );
-		$this->assertEquals( $expected_prefix, get_option( 'wp_object_cache_key_prefix_the_type' ) );
-
 		$key             = $expected_prefix . 'the_id';
-		$expected_cached = array( 'data' => $object );
+
-		$this->assertEquals( $expected_cached, $this->cache_engine->cache[ $key ] );
+		$this->assertEquals( $object, wp_cache_get( $key, 'the_type' ) );
 	}
 
 	/**
@@ -165,34 +163,16 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 	 */
 	public function test_setting_two_objects_result_in_same_prefix() {
 		$object_1 = array( 'foo' );
-		$this->sut->set( 'the_id_1', $object_1 );
+		$this->sut->set( $object_1, 'the_id_1' );
 		$object_2 = array( 1, 2, 3, 4 );
-		$this->sut->set( 9999, $object_2 );
+		$this->sut->set( $object_2, 9999 );
 
-		$prefix = 'woocommerce_object_cache|the_type|random_1|';
+		$prefix = \WC_Cache_Helper::get_cache_prefix( 'the_type' );
 
 		$key_1 = $prefix . 'the_id_1';
-		$expected_cached = array( 'data' => $object_1 );
+		$this->assertEquals( $object_1, wp_cache_get( $key_1, 'the_type' ) );
-		$this->assertEquals( $expected_cached, $this->cache_engine->cache[ $key_1 ] );
 		$key_2 = $prefix . '9999';
-		$expected_cached = array( 'data' => $object_2 );
+		$this->assertEquals( $object_2, wp_cache_get( $key_2, 'the_type' ) );
-		$this->assertEquals( $expected_cached, $this->cache_engine->cache[ $key_2 ] );
-	}
-
-	/**
-	 * @testdox 'set' uses the default expiration value if no explicit value is passed.
-	 */
-	public function test_set_with_default_expiration() {
-		$this->sut->set( 'the_id', array( 'foo' ) );
-		$this->assertEquals( $this->sut->get_default_expiration_value(), $this->cache_engine->last_expiration );
-	}
-
-	/**
-	 * @testdox 'set' uses the explicitly passed expiration value.
-	 */
-	public function test_set_with_explicit_expiration() {
-		$this->sut->set( 'the_id', array( 'foo' ), 1234 );
-		$this->assertEquals( 1234, $this->cache_engine->last_expiration );
 	}
 
 	/**
@@ -202,7 +182,7 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 		$this->expectException( CacheException::class );
 		$this->expectExceptionMessage( "Null id supplied and the cache class doesn't implement get_object_id" );
 
-		$this->sut->set( null, array( 'foo' ) );
+		$this->sut->set( array( 'foo' ) );
 	}
 
 	/**
@@ -223,21 +203,28 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 			protected function get_random_string(): string {
 				return 'random';
 			}
+
+			protected function validate( $object ): ?array {
+				return null;
+			}
+
+			protected function get_from_datastore( $id ) {
+				return null;
+			}
 		};
 
 		// phpcs:enable Squiz.Commenting
 
-		$sut->set( null, array( 'id' => 1234 ) );
+		$sut->set( array( 'id' => 1234 ) );
 
-		$this->assertEquals( 'woocommerce_object_cache|the_type|random|1235', array_keys( $this->cache_engine->cache )[0] );
+		$this->assertEquals( array( 'id' => 1234 ), $sut->get( '1235' ) );
 	}
 
 	/**
-	 * @testdox 'set' caches the value returned by 'serialize'.
+	 * @testdox 'update_if_cached' does nothing if no object is cached with the passed (or obtained) id.
 	 */
-	public function test_set_with_custom_serialization() {
+	public function test_update_if_cached_does_nothing_for_not_cached_id() {
-		$object = array( 'foo' );
+		$id = 1234;
-
 		// phpcs:disable Squiz.Commenting
 
 		$sut = new class() extends ObjectCache {
@@ -245,18 +232,77 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 				return 'the_type';
 			}
 
-			protected function serialize( $object ): array {
+			protected function get_object_id( $object ) {
-				return array( 'the_data' => $object );
+				return $object['id'];
+			}
+
+			protected function validate( $object ): ?array {
+				return null;
+			}
+
+			protected function get_from_datastore( $id ) {
+				return null;
 			}
 		};
 
 		// phpcs:enable Squiz.Commenting
 
-		$sut->set( 1234, $object );
+		$result = $sut->update_if_cached( array( 'id' => 1234 ), $id );
+		$this->assertFalse( $result );
+		$this->assertEmpty( $sut->get( $id ) );
+	}
 
-		$cached   = array_values( $this->cache_engine->cache )[0];
+	/**
-		$expected = array( 'the_data' => $object );
+	 * @testdox 'update_if_cached' updates an already cached object the same way as 'set'.
-		$this->assertEquals( $expected, $cached );
+	 */
+	public function test_update_if_cached_updates_already_cached_object() {
+		$id = 1234;
+		// phpcs:disable Squiz.Commenting
+
+		$sut = new class() extends ObjectCache {
+			public function get_object_type(): string {
+				return 'the_type';
+			}
+
+			protected function get_object_id( $object ) {
+				return $object['id'];
+			}
+
+			protected function get_random_string(): string {
+				return 'random';
+			}
+
+			protected function validate( $object ): ?array {
+				return null;
+			}
+
+			protected function get_from_datastore( $id ) {
+				return null;
+			}
+		};
+
+		// phpcs:enable Squiz.Commenting
+
+		$sut->set( array( 'id' => 1234 ), $id );
+		$this->assertEquals( array( 'id' => 1234 ), $sut->get( $id ) );
+
+		$new_value = array(
+			'id'  => 1234,
+			'foo' => 'bar',
+		);
+		$result    = $sut->update_if_cached( $new_value, $id );
+		$this->assertTrue( $result );
+		$this->assertEquals( $new_value, $sut->get( $id ) );
+	}
+
+	/**
+	 * @testdox 'update_if_cached' throws an exception if no object id is passed and the class doesn't implement 'get_object_id'.
+	 */
+	public function test_update_if_cached_null_id_without_id_retrieval_implementation() {
+		$this->expectException( CacheException::class );
+		$this->expectExceptionMessage( "Null id supplied and the cache class doesn't implement get_object_id" );
+
+		$this->sut->update_if_cached( array( 'foo' ) );
 	}
 
 	/**
@@ -288,12 +334,20 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 			protected function validate( $object ): array {
 				return $this->errors;
 			}
+
+			protected function get_from_datastore( $id ) {
+				return null;
+			}
+
+			protected function get_object_id( $object ) {
+				return $object['id'];
+			}
 		};
 
 		// phpcs:enable Squiz.Commenting
 
 		try {
-			$sut->set( 1234, $object );
+			$sut->set( $object, 1234 );
 		} catch ( CacheException $thrown ) {
 			$exception = $thrown;
 		}
@@ -343,7 +397,7 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 	 */
 	public function test_try_getting_previously_cached_object() {
 		$object = array( 'foo' );
-		$this->sut->set( 'the_id', $object );
+		$this->sut->set( $object, 'the_id' );
 
 		$result = $this->sut->get( 'the_id' );
 		$this->assertEquals( $object, $result );
@@ -369,115 +423,15 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 
 		$expected = array( 'id' => 'the_id' );
 		$this->assertEquals( $expected, $result );
-		$this->assertEquals( array( 'data' => $expected ), array_values( $this->cache_engine->cache )[0] );
+		$this->assertEquals( $expected, $this->sut->get( 'the_id' ) );
-		$this->assertEquals( $this->sut->get_default_expiration_value(), $this->cache_engine->last_expiration );
-	}
-
-	/**
-	 * @testdox 'get' uses the passed object retrieval callback if there's no object cached under the passed id, and caches the object retrieved using the passed expiration value.
-	 */
-	public function test_try_getting_not_cached_object_with_callback_and_explicit_expiration() {
-		$expiration = 1234;
-
-		$callback = function( $id ) {
-			return array( 'id' => $id );
-		};
-
-		$result = $this->sut->get( 'the_id', $expiration, $callback );
-
-		$expected = array( 'id' => 'the_id' );
-		$this->assertEquals( $expected, $result );
-		$this->assertEquals( array( 'data' => $expected ), array_values( $this->cache_engine->cache )[0] );
-		$this->assertEquals( $expiration, $this->cache_engine->last_expiration );
-	}
-
-	/**
-	 * @testdox 'get' uses the 'get_from_datastore' method if there's no object cached under the passed id, and caches the object retrieved.
-	 */
-	public function test_try_getting_not_cached_object_get_from_datastore_implemented() {
-		// phpcs:disable Squiz.Commenting
-
-		$sut = new class() extends ObjectCache {
-			public function get_object_type(): string {
-				return 'the_type';
-			}
-
-			protected function get_from_datastore( $id ) {
-				return array( 'id' => $id );
-			}
-		};
-
-		// phpcs:enable Squiz.Commenting
-
-		$result = $sut->get( 'the_id' );
-
-		$expected = array( 'id' => 'the_id' );
-		$this->assertEquals( $expected, $result );
-		$this->assertEquals( array( 'data' => $expected ), array_values( $this->cache_engine->cache )[0] );
-		$this->assertEquals( $this->sut->get_default_expiration_value(), $this->cache_engine->last_expiration );
-	}
-
-	/**
-	 * @testdox 'get' uses the 'get_from_datastore' method if there's no object cached under the passed id, and caches the object retrieved using the passed expiration value.
-	 */
-	public function test_try_getting_not_cached_object_get_from_datastore_implemented_and_explicit_expiration() {
-		$expiration = 1234;
-
-		// phpcs:disable Squiz.Commenting
-
-		$sut = new class() extends ObjectCache {
-			public function get_object_type(): string {
-				return 'the_type';
-			}
-
-			protected function get_from_datastore( $id ) {
-				return array( 'id' => $id );
-			}
-		};
-
-		// phpcs:enable Squiz.Commenting
-
-		$result = $sut->get( 'the_id', $expiration );
-
-		$expected = array( 'id' => 'the_id' );
-		$this->assertEquals( $expected, $result );
-		$this->assertEquals( array( 'data' => $expected ), array_values( $this->cache_engine->cache )[0] );
-		$this->assertEquals( $expiration, $this->cache_engine->last_expiration );
-	}
-
-	/**
-	 * @testdox 'get' applies 'deserialize' to the object returned by the cache engine before returning it.
-	 */
-	public function test_custom_deserialization() {
-		// phpcs:disable Squiz.Commenting
-
-		$sut = new class() extends ObjectCache {
-			public function get_object_type(): string {
-				return 'the_type';
-			}
-
-			protected function deserialize( array $serialized ) {
-				$object   = $serialized['data'];
-				$object[] = 3;
-				return $object;
-			}
-		};
-
-		// phpcs:enable Squiz.Commenting
-
-		$sut->set( 'the_id', array( 1, 2 ) );
-
-		$result   = $sut->get( 'the_id' );
-		$expected = array( 1, 2, 3 );
-		$this->assertEquals( $expected, $result );
 	}
 
 	/**
 	 * @testdox 'remove' removes a cached object and returns true, or returns false if there's no cached object under the passed id.
 	 */
 	public function test_remove() {
-		$this->sut->set( 'the_id_1', array( 'foo' ) );
+		$this->sut->set( array( 'foo' ), 'the_id_1' );
-		$this->sut->set( 'the_id_2', array( 'bar' ) );
+		$this->sut->set( array( 'bar' ), 'the_id_2' );
 
 		$result_1 = $this->sut->remove( 'the_id_1' );
 		$result_2 = $this->sut->remove( 'the_id_X' );
@@ -493,15 +447,17 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 	 * @testdox 'flush' deletes the stored cache key prefix, effectively rendering the cached objects inaccessible.
 	 */
 	public function test_flush() {
-		$this->sut->set( 'the_id', array( 'foo' ) );
+		$this->sut->set( array( 'foo' ), 'the_id' );
 
+		$current_prefix_key = \WC_Cache_Helper::get_cache_prefix( 'the_type' );
 		$this->sut->flush();
-		$this->assertFalse( get_option( 'wp_object_cache_key_prefix_the_type' ) );
+		$this->assertFalse( $this->sut->is_cached( 'the_id' ) );
+		$expected_new_prefix = \WC_Cache_Helper::get_cache_prefix( 'the_type' );
+		$this->assertNotEquals( $current_prefix_key, $expected_new_prefix );
 
-		$this->sut->set( 'the_id_2', array( 'bar' ) );
+		$this->sut->set( array( 'bar' ), 'the_id_2' );
 
-		$expected_new_prefix = 'woocommerce_object_cache|the_type|random_2|';
+		$this->assertEquals( $expected_new_prefix, \WC_Cache_Helper::get_cache_prefix( 'the_type' ) );
-		$this->assertEquals( $expected_new_prefix, get_option( 'wp_object_cache_key_prefix_the_type' ) );
 		$this->assertFalse( $this->sut->is_cached( 'the_id' ) );
 		$this->assertTrue( $this->sut->is_cached( 'the_id_2' ) );
 	}
@@ -510,10 +466,9 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 	 * @testdox A custom cache engine instance can be used by overriding 'get_cache_engine_instance'.
 	 */
 	public function test_custom_cache_engine_via_protected_method() {
-		$engine = new InMemoryObjectCacheEngine();
+		$engine = new WPCacheEngine();
 
 		// phpcs:disable Squiz.Commenting
-
 		$sut = new class($engine) extends ObjectCache {
 			public function get_object_type(): string {
 				return 'the_type';
@@ -529,25 +484,51 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 			protected function get_cache_engine_instance(): CacheEngine {
 				return $this->engine;
 			}
-		};
 
+			protected function get_object_id( $object ) {
+			}
+
+			protected function validate( $object ): ?array {
+				return null;
+			}
+
+			protected function get_from_datastore( $id ) {
+			}
+		};
 		// phpcs:enable Squiz.Commenting
 
 		$object = array( 'foo' );
-		$sut->set( 'the_id', $object );
+		$sut->set( $object, 'the_id' );
 
-		$expected_cached = array( 'data' => $object );
+		$this->assertEquals( $object, $sut->get( 'the_id' ) );
-		$this->assertEquals( $expected_cached, array_values( $engine->cache )[0] );
 	}
 
 	/**
 	 * @testdox A custom cache engine instance can be used via 'wc_object_cache_get_engine' filter.
 	 */
 	public function test_custom_cache_engine_via_hook() {
-		$engine                  = new InMemoryObjectCacheEngine();
+		$engine                  = new class() extends WPCacheEngine {};
 		$engine_passed_to_filter = null;
 		$cache_passed_to_filter  = null;
 
+		$sut = new class() extends ObjectCache {
+			// phpcs:disable Squiz.Commenting
+			public function get_object_type(): string {
+				return 'the_type';
+			}
+
+			protected function get_object_id( $object ) {
+			}
+
+			protected function validate( $object ): ?array {
+				return null;
+			}
+
+			protected function get_from_datastore( $id ) {
+			}
+			// phpcs:enable Squiz.Commenting
+		};
+
 		add_filter(
 			'wc_object_cache_get_engine',
 			function( $old_engine, $cache ) use ( $engine, &$engine_passed_to_filter, &$cache_passed_to_filter ) {
@@ -560,131 +541,11 @@ class ObjectCacheTest extends \WC_Unit_Test_Case {
 		);
 
 		$object = array( 'foo' );
-		$this->sut->set( 'the_id', $object );
+		$sut->set( $object, 'the_id' );
 
-		$expected_cached = array( 'data' => $object );
+		$this->assertEquals( $object, $sut->get( 'the_id' ) );
-		$this->assertEquals( $expected_cached, array_values( $engine->cache )[0] );
 
-		$this->assertEquals( $engine_passed_to_filter, wc_get_container()->get( WpCacheEngine::class ) );
+		$this->assertEquals( $engine_passed_to_filter, wc_get_container()->get( WPCacheEngine::class ) );
-		$this->assertEquals( $cache_passed_to_filter, $this->sut );
+		$this->assertEquals( $cache_passed_to_filter, $sut );
-	}
-
-	/**
-	 * @testdox 'woocommerce_after_serializing_{type}_for_caching' allows to modify the serialized object before being cached.
-	 */
-	public function test_modifying_serialized_object_via_filter() {
-		$object_passed_to_filter = null;
-		$id_passed_to_filter     = null;
-
-		add_filter(
-			'woocommerce_after_serializing_the_type_for_caching',
-			function( $data, $object, $id ) use ( &$object_passed_to_filter, &$id_passed_to_filter ) {
-				$object_passed_to_filter = $object;
-				$id_passed_to_filter     = $id;
-
-				$data['foo'] = 'bar';
-				return $data;
-			},
-			10,
-			3
-		);
-
-		$object = array( 'fizz' );
-		$this->sut->set( 'the_id', $object );
-
-		$expected_cached = array(
-			'data' => $object,
-			'foo'  => 'bar',
-		);
-		$this->assertEquals( $expected_cached, array_values( $this->cache_engine->cache )[0] );
-
-		$this->assertEquals( $object, $object_passed_to_filter );
-		$this->assertEquals( 'the_id', $id_passed_to_filter );
-	}
-
-	/**
-	 * @testdox 'woocommerce_after_deserializing_{type}_from_cache' allows to modify the deserialized object before it's returned by 'get'.
-	 */
-	public function test_modifying_deserialized_object_via_filter() {
-		$object_passed_to_filter = null;
-		$id_passed_to_filter     = null;
-		$data_passed_to_filter   = null;
-
-		$original_object    = array( 'foo' );
-		$replacement_object = array( 'bar' );
-
-		add_filter(
-			'woocommerce_after_deserializing_the_type_from_cache',
-			function( $object, $data, $id ) use ( &$object_passed_to_filter, &$id_passed_to_filter, &$data_passed_to_filter, $replacement_object ) {
-				$object_passed_to_filter = $object;
-				$id_passed_to_filter     = $id;
-				$data_passed_to_filter   = $data;
-
-				return $replacement_object;
-			},
-			10,
-			3
-		);
-
-		$this->sut->set( 'the_id', $original_object );
-		$retrieved_object = $this->sut->get( 'the_id' );
-
-		$this->assertEquals( $replacement_object, $retrieved_object );
-
-		$this->assertEquals( $original_object, $object_passed_to_filter );
-		$this->assertEquals( array( 'data' => $original_object ), $data_passed_to_filter );
-		$this->assertEquals( 'the_id', $id_passed_to_filter );
-	}
-
-	/**
-	 * @testdox 'remove' triggers the 'woocommerce_after_removing_{type}_from_cache' action.
-	 *
-	 * @testWith [true]
-	 *           [false]
-	 *
-	 * @param bool $operation_succeeds Whether the removal operation succeeds or not.
-	 */
-	public function test_action_triggered_on_object_removed_from_cache( bool $operation_succeeds ) {
-		$id_passed_to_action     = null;
-		$result_passed_to_action = null;
-
-		add_action(
-			'woocommerce_after_removing_the_type_from_cache',
-			function( $id, $result ) use ( &$id_passed_to_action, &$result_passed_to_action ) {
-				$id_passed_to_action     = $id;
-				$result_passed_to_action = $result;
-			},
-			10,
-			2
-		);
-
-		$this->sut->set( 'the_id', array( 'foo' ) );
-		$this->sut->remove( $operation_succeeds ? 'the_id' : 'INVALID_ID' );
-
-		$this->assertEquals( $operation_succeeds ? 'the_id' : 'INVALID_ID', $id_passed_to_action );
-		$this->assertEquals( $operation_succeeds, $result_passed_to_action );
-	}
-
-	/**
-	 * @testdox 'flush' triggers the 'woocommerce_after_flushing_{type}_cache' action.
-	 */
-	public function test_action_triggered_on_cache_flushed() {
-		$cache_passed_to_action  = null;
-		$engine_passed_to_action = null;
-
-		add_action(
-			'woocommerce_after_flushing_the_type_cache',
-			function( $cache, $engine ) use ( &$cache_passed_to_action, &$engine_passed_to_action ) {
-				$cache_passed_to_action  = $cache;
-				$engine_passed_to_action = $engine;
-			},
-			10,
-			2
-		);
-
-		$this->sut->flush();
-
-		$this->assertEquals( $this->sut, $cache_passed_to_action );
-		$this->assertEquals( $this->cache_engine, $engine_passed_to_action );
 	}
 }