[wp-trac] [WordPress Trac] #56055: Wrong cache created in WP_Term_Query class

[WordPress Trac]

#56055: Wrong cache created in WP_Term_Query class
--------------------------+-----------------------------
 Reporter:  kubiq         |      Owner:  (none)
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  Taxonomy      |    Version:  6.0
 Severity:  critical      |   Keywords:
  Focuses:                |
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 When you call the same `get_terms( $args )` multiple times, then the
 second (or every other call) will return wrong results - they will contain
 also empty terms

 You can easily test this on any taxonomy with some empty term
 {{{#!php
 <?php
 echo '1. call:';
 echo '<pre>' . print_r( get_terms(array( 'taxonomy' => 'product_cat',
 'parent' => 0 )), 1 ) . '</pre>';
 echo '2. call:';
 echo '<pre>' . print_r( get_terms(array( 'taxonomy' => 'product_cat',
 'parent' => 0 )), 1 ) . '</pre>';
 }}}

 logically the output should be same in the 1.call and also in 2. call, but
 it's not

 **SOLUTION:**

 In `get_terms` function inside `WP_Term_Query` class at the end there is
 `wp_cache_add( $cache_key, $terms, 'terms' );`
 but `$terms` variable contains all terms even if you have `hide_empty` set
 to `TRUE`

 *`$term_objects` is the correct variable that contains correct terms and
 it is also used in next lines

 it can be fixed by getting terms ids from `$term_objects` variable eg.
 {{{#!php
 <?php
 $correct_terms = array_map(function( $term ){ return (object)array(
 'term_id' => $term->term_id ); }, $term_objects);
 }}}

 and replace it in cache function

 {{{#!php
 <?php
 wp_cache_add( $cache_key, $correct_terms, 'terms' );
 }}}

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/56055>
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