Automatic url aliases disappearing from nodes

So I found the problem...
Whenever you delete some node, nodes with similar IDs will lose their alias. Here's why:

In the AliasStorageHelper there is this function (I moved the query into a variable while debugging):

  public function loadBySourcePrefix($source) {
    $query = $this->database->select('url_alias', 'u')
                            ->fields('u', array('pid'))
                            ->condition('source', $source . '%', 'LIKE')
                            ->execute()
                            ->fetchCol();

    return $query;
  }

The $source contains a string, e.g. for nodes: /node/10

The condition on the query turns this into /node/10%, thus effectively selecting all nodes which start with nid "10": /node/100, /node/101, ... And by that deleting all the aliases for these nodes in deleteSourceByPrefix().

I checked an older project using an older version of pathauto, there the function is different:

  public function loadBySourcePrefix($source) {
    return $this->database->query("SELECT pid FROM {url_alias} WHERE source = :source OR source LIKE :source_wildcard",
      [':source' => $source, ':source_wildcard' => $source . '/%'])
      ->fetchCol();
  }

In this version there's a slash in front of the wildcard, making the query only select /node/10 and /node/10/% which works correctly.

It seems the bug was introduced by a typo when refactoring.

Here's a patch.

I followed the logic of the previous version, with an orConditionGroup I check for /node/[nid] and /node/[nid]/%.
The same query was being used in countBySourcePrefix() so I updated that part as well.

Could you give me a hand on the test, or point me in the right direction? Not sure on how to do that.

Great! Webflo, thanks for the help :)