address-name-migration.php

<?php
function address_test_bullshit() {
  // Save a list of processed fields so that we can do clean up once the
  // original data is migrated.
  $processed_fields = [];
  $columns_to_add = ['family_name', 'additional_name', 'given_name'];

  $field_type_manager = \Drupal::getContainer()->get('plugin.manager.field.field_type');
  $address_definition = $field_type_manager->getDefinition('address');
  /** @var \Drupal\address\Plugin\Field\FieldType\AddressItem $class */
  $class = $address_definition['class'];
  $field_schema = $class::schema($this);

  $schema = \Drupal::database()->schema();
  $entity_type_manager = \Drupal::getContainer()->get('entity_type.manager');
  $entity_field_manager = \Drupal::getContainer()->get('entity_field.manager');
  $entity_field_map = \Drupal::getContainer()->get('entity_field.manager')->getFieldMapByFieldType('address');
  // The key-value collection for tracking installed storage schema.
  $entity_storage_schema_sql = \Drupal::keyValue('entity.storage_schema.sql');
  $entity_definitions_installed = \Drupal::keyValue('entity.definitions.installed');

  foreach ($entity_field_map as $entity_type_id => $field_map) {
    $entity_storage = $entity_type_manager->getStorage($entity_type_id);
    // Only SQL storage based entities are supported / throw known exception.
    if ($entity_storage instanceof SqlContentEntityStorage) {
      $field_storage_definitions = $entity_field_manager->getFieldStorageDefinitions($entity_type_id);
      /** @var Drupal\Core\Entity\Sql\DefaultTableMapping $table_mapping */
      $table_mapping = $entity_storage->getTableMapping($field_storage_definitions);
      // Only need field storage definitions of address fields.
      /** @var \Drupal\Core\Field\FieldStorageDefinitionInterface $field_storage_definition */
      foreach (array_intersect_key($field_storage_definitions, $field_map) as $field_storage_definition) {
        // Get the current field's name.
        $field_name = $field_storage_definition->getName();
        $processed_fields[$field_name] = $entity_type_id;
        // We need to know the schema column name for the old `recipient` value.
        $initial_from_field = $table_mapping->getFieldColumnName($field_storage_definition, 'recipient');
        // Get the name of the field's table.
        $table = $table_mapping->getFieldTableName($field_name);

        // Loop over each new column and add it as a schema column change.
        foreach ($columns_to_add as $column_id) {
          $column = $table_mapping->getFieldColumnName($field_storage_definition, $column_id);

          // Add `initial_from_field` to the new spec, as this will copy over
          // the entire data.
          $spec = $field_schema['columns'][$column_id];

          // We will not seed data into `additional_name`.
          if ($column_id != 'additional_name') {
            $spec += [
              'initial_from_field' => $initial_from_field,
            ];
          }

          // Add the new column.
          $schema->addField($table, $column, $spec);

          // Update the installed storage schema for this field as well.
          $key = "$entity_type_id.field_schema_data.$field_name";
          if ($field_schema_data = $entity_storage_schema_sql->get($key)) {
            $field_schema_data[$table]['fields'][$column_id] = $field_schema['columns'][$column_id];
            $entity_storage_schema_sql->set($key, $field_schema_data);
          }
          if ($table_mapping->allowsSharedTableStorage($field_storage_definition)) {
            $key = "$entity_type_id.field_storage_definitions";
            if ($definitions = $entity_definitions_installed->get($key)) {
              $definitions[$field_name] = $field_storage_definition;
              $entity_definitions_installed->set($key, $definitions);
            }
          }
        }
        // Once all columns added, and data copied. Delete the field.
        $schema->dropField($table, $initial_from_field);
      }
    }
  }

}