Added entity type / bundle field usage report

    class: \Drupal\migrate_expansion\Command\Analysis\ParagraphsHierarchy

    tags:

      - { name: drush.command }

  migrate_expansion.commands.analysis.entity_field_usage:

    class: \Drupal\migrate_expansion\Command\Analysis\EntityFieldUsage

    tags:

      - { name: drush.command }

<?php

namespace Drupal\migrate_expansion\Command\Analysis;

use Drupal\Core\Database\Connection;

use Drupal\Core\Database\Database;

use Drush\Commands\DrushCommands;

/**

 * Class EntityFieldUsage.

 */

class EntityFieldUsage extends DrushCommands {

  /**

   * Renders a list of field usage data per entity type and bundle.

   *

   * @param string $legacy_db_key .

   *   The database connection key for the D7 database.

   * @param string $entity_type

   *   The entity type for which to retrieve field usage data.

   *

   * @option $format

   *   The format to print the data to. Don't pass anything to show a table.

   *   Accepts any of the Drush's built-in formats.

   *

   * @usage migrate_expansion:analysis:entity-field-usage $legacy_key $entity_type

   *   --format=csv

   * @usage migrate_expansion:analysis:entity-field-usage $legacy_key $entity_type

   *

   * @command migrate_expansion:analysis:entity-field-usage

   *

   * @return array|void

   */

  public function entityFieldUsage($legacy_db_key, $entity_type, $options = ['format' => NULL]) {

    $connection = Database::getConnection('default', $legacy_db_key);

    $field_list = $this->getFieldsPerEntityType($connection, $entity_type);

    $headers = ['Entity Type', 'Bundle', 'Field Name', 'Count'];

    $table = [];

    foreach ($field_list as $item) {

      $field_count = $connection->query("SELECT count(*) FROM field_data_{$item->field_name} fd

        WHERE fd.bundle = :bundle",

        [

          ':bundle' => $item->bundle,

        ])

        ->fetchField();

      $table[] = [

        $entity_type, $item->bundle, $item->field_name, $field_count,

      ];

    }

    // No format specified. Print table.

    if (empty($options['format'])) {

      $this->io()->table($headers, $table);

      return;

    }

    array_unshift($table, $headers);

    return $table;

  }

  /**

   * @param \Drupal\Core\Database\Connection $connection

   *

   * @return mixed

   */

  protected function getFieldsPerEntityType(Connection $connection, string $entity_type) {

    $fields = $connection->query("SELECT fci.field_name, fci.entity_type, fci.bundle FROM field_config_instance fci

      WHERE fci.entity_type = :entity_type

      ORDER BY fci.bundle ASC",

      [

        ':entity_type' => $entity_type,

      ])

      ->fetchAll();

    return $fields;

  }

}