Error “implode(): Invalid arguments” when using register_rest_route

Hello,

I’ve encountered an issue that was causing me some problems; when using wp_add_object_terms with register_rest_route it gives this error:

Warning: implode(): Invalid arguments passed in C:\wamp64\www\wp-tester\wp-content\plugins\wp-security-audit-log\classes\Sensors\Content.php on line 898

PHP code example:

add_action( 'rest_api_init', function () {
    register_rest_route( 'my-rest-route/v1', '/example/', array(
    'methods' => 'POST',
    'callback' => 'rest_api_callback_action'
  ));
});
function rest_api_callback_action($request)
{
  $testAddCat = wp_add_object_terms(5, 'test-category', 'custom-categories');
  echo 'Success';
  die();
}

While I am using a custom post type and assigning a category from a custom taxonomy when the rest API is called in the example above, the issue persists when assigning a default category to a default post.

It appears that in the Content.php file the function gutenberg_post_terms_changed calls $this->CheckCategoriesChange() but does not pass any value for the $old_cats parameter. As a temporary fix I’ve added a couple if statements:

protected function CheckCategoriesChange( $old_cats, $new_cats, $post ) {
if( !is_array($old_cats) ) {
  $old_cats = array();
}
if( !is_array($new_cats) ) {
 $new_cats = array();			
}
$old_cats = implode( ', ', $old_cats );
$new_cats = implode( ', ', $new_cats );
...

Other Details:

• WordPress version: 4.9.8
• WP Security Audit Log plugin version: 3.2.4
• No other WordPress plugins active, only the default Hello Dolly and Akismet Anti-Spam are installed but inactive.
• Fresh local install with wampserver 3.1.0
• PHP version 5.6.31

Cheers!

• This topic was modified 7 years, 6 months ago by patternmb. Reason: Made other details, slightly more clear