1

We've made a migration from the City of Helsinki's Linked Events API, and during this work we've been seeing these migration messages:

Array index missing, extraction failed

Here is an example of an event that works nicely: https://api.hel.fi/linkedevents/v1/event/hko:14004/

And one that causes the error: https://api.hel.fi/linkedevents/v1/event/matko:16134/

In the latter you see that offers is returned as an empty array. We're using the skip_on_empty plugin to handle those:

field_offers_is_free:
  -
    plugin: skip_on_empty
    method: process
    source: offers
  -
    plugin: extract
    index:
      - 0
      - is_free
field_offers_info_url:
  -
    plugin: skip_on_empty
    method: process
    source: offers
  -
    plugin: extract
    default: false
    index:
      - 0
      - info_url
      - fi

The problem is that never reaches the skip_on_empty plugin. I've been stepping through this in the debugger based on my findings I created an issue in Drupal Core https://www.drupal.org/node/2905929

When Get sets $multiple to true, processRow() in MigrateExecutable runs a foreach () on an empty array - resulting in the skip_on_empty plugin to be skipped.

Is there something wrong in our setup or did I uncover a bug? Any ideas on how to work smoothly around this?

2

I solved this by creating my own migrate plugin that sets the multiple flag to false if we get an empty array, like this:

/**
 * The Get plugin causes issues for us when it fetches and array that is empty.
 *
 * It sets multiple to true which prevents the skip_on_empty plugin from being
 * triggered.
 * @see https://www.drupal.org/node/2905929
 *
 * @MigrateProcessPlugin(
 *   id = "get_array_fix_multiple",
 *   handle_multiples = TRUE
 * )
 */

class GetArrayFixMultiple extends ProcessPluginBase {

  /**
   * Flag indicating whether there are multiple values.
   *
   * @var bool
   */
  protected $multiple;

  /**
   * {@inheritdoc}
   */
  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
      $array = is_array($value);
      $empty = empty($value);
      $this->multiple = $array && !$empty;
      return $value;
  }

  /**
   * {@inheritdoc}
   */
  public function multiple() {
    return $this->multiple;
  }

}

Either the bug is in the get plugin or then skip_on_empty should support multiple.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.