wp_set_post_categories fails if input array index starts with other than 0

[borgar]

wp_set_post_categories is defected in that if it is passed a an array of categories who's index starts at other than 0, it returns without any action. I noticed this when tracking another issue in Textpattern import.

Example:

$cats = array();
$cats[1] = 10;
wp_set_post_categories($postID, $cats);

This fails because (1==count($cats) && ''==$cats[ 0 ]) == true.

Further, I feel that inconsistent checking behavior needs addressing. Why should this function return true in the single case where it gets an array of values where [0]=='' ?

My suggestion is to use this:

if (!is_array($post_categories) || '' == implode($post_categories))
  $post_categories = array(get_option('default_category'));

[ryan]

It was probably done to work around some bug in the dark past. We can probably get rid of it, but a more conservative fix would be to add an isset on $post_categories[0] to that else if so that you don't get caught by the early return.

[wojtek.szkutnik]

Related?: ​http://bugs.php.net/bug.php?id=38478 @reset

[wojtek.szkutnik]

or not.

[wonderboymusic]

This now works no prob - patch added:

wp_set_post_categories( 1, array( '', 9 ) );

[wonderboymusic]

This works now in core:

php -r "require( 'wp-load.php' );  
wp_set_post_categories( 1, array( '', '', '', '', '', '', 7, 8, 9 ) ); "

[SergeyBiryukov]

Duplicate of #13246.