Where and how are escape quotes stripped when saving a taxonomy terms which include comas or quotes?

Question

in taxonomy_autocomplete: https://api.drupal.org/api/drupal/modules!taxonomy!taxonomy.pages.inc/function/taxonomy_autocomplete/6 we have the following code:

   // Commas and quotes in terms are special cases, so encode 'em.
      if (strpos($tag->name, ',') !== FALSE || strpos($tag->name, '"') !== FALSE) {
        $n = '"' . str_replace('"', '""', $tag->name) . '"';
      }

Imagine we have the taxonomy term which is exactly the following string:

George "madcow" Stewart

THe above code would cause the taxonomy autocomplete to display:

"George ""madcow"" Stewart"

I have re-implemented the taxonomy_autocomplete in order to work with a single term (no comma separated list of terms allowed). The problem now is that when we want to enter George "madcow" Stewart, a new term "George ""madcow"" Stewart" is created, including all the extra quotes!

I cannot find where and how in core the escape quotes are stripped before insertion to the database…

Answer 1

Oh! I just found it:

The function taxonomy_node_save(&$node, $terms) calls drupal_explode_tags()

https://api.drupal.org/api/drupal/includes!common.inc/function/drupal_explode_tags/6

which has:

// If a user has escaped a term (to demonstrate that it is a group,
// or includes a comma or quote character), we remove the escape
// formatting so to save the term into the database as the user intends.
$tag = trim(str_replace('""', '"', preg_replace('/^"(.*)"$/', '\1', $tag)));