Metatag canonicals are broken, q is multiplied

Drupal integration for CiviCRM has hook implementation for hook_metatag_metatags_view_alter(). This implementation is done a bit wrong way, as it adds Drupals "q" query parameter as visible query part to urls. And this breaks canonicals for normal Drupal pages when clean urls are enabled.

Case:

Drupal 7 with token and metatag modules enabled and with CiviCRM (4.6.2), running on nginx + php-fpm, clean urls enabled. For nodes, canonicals are defined, with metatag module, to: [current-page:url:unaliased:absolute]

Before hook_metatag_metatags_view_alter() implementations are called, canonical has right content. For example if URL to page is "http://www.domain.tld/node/1234" canonical is "http://www.domain.tld/node/1234". But after CiviCRMs implementation is executed canonical is changed to "http://www.domain.tld/node/1234?q=node/1234".

This happens because commits that fix issue CRM-15871 are done a bit wrong way.

Proposed resolution

Query parameters should be get with function drupal_get_query_parameters() or otherwise also query parameter q should be removed.

Instead of custom function, _civicrm_get_url_parameters(), I strongly suggest that only use of that function is replaced with drupal_get_query_parameters(). All query excludes can be handled with drupal_get_query_parameters().