Refactor meta migrator to follow pattern in meta to custom migrator.

plugins/woocommerce/src/Database/Migrations/CustomOrderTable/MetaToMetaTableMigrator.php

@@ -14,7 +14,7 @@ use Automattic\WooCommerce\Database\Migrations\MigrationHelper;
  *
  * @package Automattic\WooCommerce\Database\Migrations\CustomOrderTable
  */
-class MetaToMetaTableMigrator {
+abstract class MetaToMetaTableMigrator {
 
 	/**
 	 * Schema config, see __construct for more details.
@@ -24,14 +24,29 @@ class MetaToMetaTableMigrator {
 	private $schema_config;
 
 	/**
-	 * MetaToMetaTableMigrator constructor.
+	 * Store errors along with entity IDs from migrations.
 	 *
-	 * @param array $schema_config This parameters provides general but essential information about tables under migrations. Must be of the form-
+	 * @var array
-	 * TODO: Add structure.
 	 */
-	public function __construct( $schema_config ) {
+	protected $errors;
-		// TODO: Validate params.
+
-		$this->schema_config = $schema_config;
+	public abstract function get_meta_config();
+
+	public function __construct() {
+		$this->schema_config = $this->get_meta_config();
+		$this->errors = array();
+	}
+
+	public function process_migration_batch_for_ids( $entity_ids ) {
+		global $wpdb;
+		$data_to_migrate = $this->fetch_data_for_migration_for_ids( $entity_ids );
+		$insert_queries  = $this->generate_insert_sql_for_batch( $data_to_migrate['data'], 'insert' );
+		// phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared -- $insert_queries should already be escaped in the generating function.
+		$result = $wpdb->query( $insert_queries );
+		if ( count( $data_to_migrate['data'] ) !== $result ) {
+			// TODO: Find and log entity ids that were not inserted.
+			echo 'error';
+		}
 	}
 
 	/**

plugins/woocommerce/src/Database/Migrations/CustomOrderTable/WPPostMetaToOrderMetaMigrator.php

@@ -0,0 +1,55 @@
+<?php
+
+namespace Automattic\WooCommerce\Database\Migrations\CustomOrderTable;
+
+class WPPostMetaToOrderMetaMigrator extends MetaToMetaTableMigrator {
+
+	private $excluded_columns;
+
+	public function __construct( $excluded_columns ) {
+		$this->excluded_columns = $excluded_columns;
+		parent::__construct();
+	}
+
+	/**
+	 * Generate config for meta data migration.
+	 *
+	 * @return array Meta data migration config.
+	 */
+	public function get_meta_config() {
+		global $wpdb;
+		// TODO: Remove hardcoding.
+		$this->table_names = array(
+			'orders'    => $wpdb->prefix . 'wc_orders',
+			'addresses' => $wpdb->prefix . 'wc_order_addresses',
+			'op_data'   => $wpdb->prefix . 'wc_order_operational_data',
+			'meta'      => $wpdb->prefix . 'wc_orders_meta',
+		);
+
+		return array(
+			'source'      => array(
+				'meta'          => array(
+					'table_name'        => $wpdb->postmeta,
+					'entity_id_column'  => 'post_id',
+					'meta_key_column'   => 'meta_key',
+					'meta_value_column' => 'meta_value',
+				),
+				'excluded_keys' => $this->excluded_columns,
+			),
+			'destination' => array(
+				'meta'   => array(
+					'table_name'        => $this->table_names['meta'],
+					'entity_id_column'  => 'order_id',
+					'meta_key_column'   => 'meta_key',
+					'meta_value_column' => 'meta_value',
+					'entity_id_type'    => 'int',
+				),
+				'entity' => array(
+					'table_name'       => $this->table_names['orders'],
+					'source_id_column' => 'post_id',
+					'id_column'        => 'id',
+				),
+			),
+		);
+	}
+}

plugins/woocommerce/src/Database/Migrations/CustomOrderTable/WPPostToCOTMigrator.php

@@ -66,58 +66,13 @@ class WPPostToCOTMigrator {
 		$this->shipping_address_table_migrator = new WPPostToOrderAddressTableMigrator( 'shipping' );
 		$this->operation_data_table_migrator   = new WPPostToOrderOpTableMigrator();
 
-		$meta_data_config = $this->get_config_for_meta_table();
-
-		$this->meta_table_migrator = new MetaToMetaTableMigrator( $meta_data_config );
-
-		$this->error_logger = new MigrationErrorLogger();
-	}
-
-	/**
-	 * Generate config for meta data migration.
-	 *
-	 * @return array Meta data migration config.
-	 */
-	private function get_config_for_meta_table() {
-		global $wpdb;
-		// TODO: Remove hardcoding.
-		$this->table_names = array(
-			'orders'    => $wpdb->prefix . 'wc_orders',
-			'addresses' => $wpdb->prefix . 'wc_order_addresses',
-			'op_data'   => $wpdb->prefix . 'wc_order_operational_data',
-			'meta'      => $wpdb->prefix . 'wc_orders_meta',
-		);
-
 		$excluded_columns = array_keys( $this->order_table_migrator->get_meta_column_config() );
 		$excluded_columns = array_merge( $excluded_columns, array_keys( $this->billing_address_table_migrator->get_meta_column_config() ) );
 		$excluded_columns = array_merge( $excluded_columns, array_keys( $this->shipping_address_table_migrator->get_meta_column_config() ) );
 		$excluded_columns = array_merge( $excluded_columns, array_keys( $this->operation_data_table_migrator->get_meta_column_config() ) );
 
-		return array(
+		$this->meta_table_migrator             = new WPPostMetaToOrderMetaMigrator( $excluded_columns );
-			'source'      => array(
+		$this->error_logger                    = new MigrationErrorLogger();
-				'meta'          => array(
-					'table_name'        => $wpdb->postmeta,
-					'entity_id_column'  => 'post_id',
-					'meta_key_column'   => 'meta_key',
-					'meta_value_column' => 'meta_value',
-				),
-				'excluded_keys' => $excluded_columns,
-			),
-			'destination' => array(
-				'meta'   => array(
-					'table_name'        => $this->table_names['meta'],
-					'entity_id_column'  => 'order_id',
-					'meta_key_column'   => 'meta_key',
-					'meta_value_column' => 'meta_value',
-					'entity_id_type'    => 'int',
-				),
-				'entity' => array(
-					'table_name'       => $this->table_names['orders'],
-					'source_id_column' => 'post_id',
-					'id_column'        => 'id',
-				),
-			),
-		);
 	}
 
 	/**
@@ -135,6 +90,7 @@ class WPPostToCOTMigrator {
 		$this->process_migration_for_ids( $order_post_ids );
 		$last_post_migrated = max( $order_post_ids );
 		$this->update_checkpoint( $last_post_migrated );
+
 		return false;
 	}
 
@@ -148,27 +104,10 @@ class WPPostToCOTMigrator {
 		$this->billing_address_table_migrator->process_migration_batch_for_ids( $order_post_ids );
 		$this->shipping_address_table_migrator->process_migration_batch_for_ids( $order_post_ids );
 		$this->operation_data_table_migrator->process_migration_batch_for_ids( $order_post_ids );
-		$this->process_meta_migration( $order_post_ids );
+		$this->meta_table_migrator->process_migration_batch_for_ids( $order_post_ids );
 		// TODO: Return merged error array.
 	}
 
-	/**
-	 * Process migration for metadata for given post ids.
-	 *
-	 * @param array $order_post_ids Post IDs.
-	 */
-	private function process_meta_migration( $order_post_ids ) {
-		global $wpdb;
-		$data_to_migrate = $this->meta_table_migrator->fetch_data_for_migration_for_ids( $order_post_ids );
-		$insert_queries  = $this->meta_table_migrator->generate_insert_sql_for_batch( $data_to_migrate['data'], 'insert' );
-		// phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared -- $insert_queries should already be escaped in the generating function.
-		$result = $wpdb->query( $insert_queries );
-		if ( count( $data_to_migrate['data'] ) !== $result ) {
-			// TODO: Find and log entity ids that were not inserted.
-			echo 'error';
-		}
-	}
-
 	/**
 	 * Method to migrate single record.
 	 *