Migrate empty, <nolink> and <none> link field

Not a huge deal, but links meant to be external-only are getting and can’t be saved.

I just extended the functionality and added a revert to handle it. 🚀

use Drupal\link\Plugin\migrate\process\FieldLink as DrupalFieldLink;
use Drupal\migrate\Attribute\MigrateProcess;

#[MigrateProcess('my_field_link')]
final class FieldLink extends DrupalFieldLink {

  protected function canonicalizeUri($uri) {
    $uri = parent::canonicalizeUri($uri);
    if ($uri === 'route:<nolink>') {
      return '';
    }

    return $uri;
  }
}

Not sure how to check if external only is on the field settings, but this works to get the migration done

Not a huge deal, but links meant to be external-only are getting and can’t be saved.

This should probably be a new issue, I'd like to explore this a bit. We may want to add a 'allow empty' option or something, but I'd need to see some tests (and go back and look at D7) to see how we could get ourselves into a situation with a blank external only uri and what happens in the migration.

@mikelutz 🐛 Fix migration issue for link fields with ‘External links only’ enabled Active fill your boots ;)