How to remove tag from SelectQuery object

Question

I process SelectQuery object using hook_query_TAG_after() or hook_query_alter().

I want to remove 'mytag' tag, which has been added as $query->addTag('mytag') somewhere else. Apparently, neither SelectQuery, nor QueryAlterableInterface has appropriate interface method.

Is there any means (besides SelectQuery subclassing) that I can use to remove a tag?

The reason may be the following (thanks Clive for asking):

I want to make a decision based on (expected) record set size inside hook_query_TAG_after()

I could do $countQuery = $query->countQuery(); $total = $countQuery->execute()->fetchField()

But, the cloned query will have same tag as original one and execute() will invoke the same hook ad infinitum.

Answer 1

I still can not find a way to remove a tag from query, but I found solution for my case of count query. The idea is to use another tag to stop endless recursion:

function mymodule_query_mytag_alter(QueryAlterableInterface $query) {

  if ($query->hasTag('counted')) {
    return;
  }

  // Prepare count query
  $countQuery = $query->countQuery();
  $countQuery->addTag('counted'); // Abort hook recursion

  $tables =& $countQuery->getTables(); // Query may have sub-queries

  foreach ($tables as &$table) { // Tag all subqueries
    if ($table['table'] instanceof SelectQueryInterface) {
      $table['table']->addTag('counted'); // Abort hook recursion
    }
  }

  $total = $countQuery->execute()->fetchField(); // execute() will initiate recursion!

 // Rest of processing

}

Answer 2

You should use something like this:

    $new_query = clone($db_query);
    unset($new_query->alterTags['search_api_db_facets_base']);
    if (empty($new_query->alterTags)) {
      unset($new_query->alterTags);
    }
    $search_api_current_entities = $new_query->execute()->fetchAll();