[wp-trac] [WordPress Trac] #63488: Wrong return value for get_category_by_path()

[WordPress Trac]

#63488: Wrong return value for get_category_by_path()
--------------------------+------------------------------
 Reporter:  milana_cap    |       Owner:  (none)
     Type:  defect (bug)  |      Status:  new
 Priority:  normal        |   Milestone:  Awaiting Review
Component:  Taxonomy      |     Version:
 Severity:  normal        |  Resolution:
 Keywords:  has-patch     |     Focuses:  docs
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Comment (by SergeyBiryukov):

 Hi there, thanks for the ticket.

 This is an interesting one. As noted above, `get_term()` can return a
 `WP_Error` if either the term ID is empty or the taxonomy does not exist.
 So `get_category_by_path()` can return a `WP_Error` via `get_term()`, but
 it's not easy to trigger that within normal workflow. I think the only
 case would be when the matching category somehow has an empty `term_id`
 value, which is technically possible to reproduce by editing the database
 or using the `get_terms` filter:
 {{{
 add_filter( 'get_terms', function( $terms ) {
         foreach ( $terms as $key => $term ) {
                 $terms[ $key ]->term_id = 0;
         }

         return $terms;
 });

 var_dump( get_category_by_path( 'uncategorized' ) );

 object(WP_Error)#743 (3) {
   ["errors"]=>
   array(1) {
     ["invalid_term"]=>
     array(1) {
       [0]=>
       string(11) "Empty Term."
     }
   }
   ["error_data"]=>
   array(0) {
   }
   ["additional_data":protected]=>
   array(0) {
   }
 }
 }}}

 I also tried unregistering the `category` taxonomy to see if that would
 produce a similar outcome, but `unregister_taxonomy()` has a check for
 built-in taxonomies, see [36243] / #35227.

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Ticket URL: <https://core.trac.wordpress.org/ticket/63488#comment:5>
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