Custom taxonomies create bad links

WP is throwing some PHP Notices in get_term_link() because it’s not finding the expected object property. And the function returns an incomplete link.

PHP Notice: Trying to get property of non-object in /wp-includes/taxonomy.php on line 2891

$taxonomy = $term->taxonomy; // line 2891

PHP Notice: Undefined property: stdClass::$taxonomy in /wp-includes/taxonomy.php on line 2901

elseif ( $t->query_var ) // line 2901

The reason for this is that the $term object doesn’t contain the expected property, because the alias in the plugin’s sql query is “_taxonomy”:

SELECT ... tt.taxonomy AS _taxonomy (sitemap-core.php line 2126)

Then inside get_term_link() the code branches to line 2904 and produces an incomplete link because $taxonomy is empty

$termlink = "?taxonomy=$taxonomy&term=$slug"; // line 2904