Multi-level term hierarchy problem - parents must be migrated before children

Nothing to do specifically with D5 - to set the parent of a term properly, the parent must have already been migrated. So, if a term pops up in the migration before its parent, it won't get a parent. We order the term migration by parent so terms with no parent come first, which will work just fine with a 2-deep hierarchy, but beyond that all bets are off.

We should add a createStub() method, so parent stubs get created and ultimately the hierarchy is preserved.

Better title.

That title was really misleading I looked at it few times and haven't entered it :)

I just checked and this problem can be fixed by migrating two times and using --update the second time. That second time gets the hierarchy in order.
I did that with Feeds some time ago and that did the trick too.

Anyway the createStub is the right approach and I'll try to make patch today.

I failed to make createStub implementation for terms. Maybe later when I'll understand the whole migration classes registration better.
For now the double import with --update option is the solution for me:)

The following subclass works for me migrating a 3-level vocabulary from Drupal 6. Might be suitable to simply add this createStub() implementation to DrupalTermMigration?

class MultiLevelTermMigration extends DrupalTerm6Migration {
  public function createStub($migration, $source_id) {
    if ($source_id[0] != 0) {
      $term = new stdClass();
      $term->name = t('Stub for term ') . $source_id[0];
      $v = taxonomy_vocabulary_machine_name_load($this->destinationVocabulary);
      $term->vid = $v->vid;
      taxonomy_term_save($term);
      if (isset($term->tid)) {
        return array($term->tid);
      }
    }
    return FALSE;
  }
}

Hi, did this also work for Drupal 5 - Drupal 7 migration?
greetings, Martijn

OK, I've added a createStub() to the base class, this should work fine now.