Warning: Invalid argument supplied for foreach() in /var/sites/lbt/wp-includes/functions.php on line 458

[sjmurdoch]

When using the ​subscribe to comments plugin, on removing a subscription the following warning message is displayed:

Warning: Invalid argument supplied for foreach() in /var/sites/lbt/wp-includes/functions.php on line 458

Although I have only been able to trigger this bug using subscribe to comments, the problem appears to be in Wordpress itself.

The function remove_subscriber() in subscribe-to-comments.php:546 calls delete_post_meta() in wp-includes/functions.php:436, with 3 parameters:

1. $post_id: 18
2. $key: "_sg_subscribe-to-comments"
3. $value: email address

On line 458 of wp-includes/functions.php, the following returns the warning:

foreach ( $cache_key as $index => $data )

This is because $cache_key, taken from $post_meta_cache$post_id?[$key] is empty.

I would have expected delete_post_meta() to have checked for $cache_key being non-empty before passing it to foreach(). If this is in fact a bug in subscribe to comments then please close this report and I will pass this onto the plugin developer.

• Wordpress version tested: wordpress-2.0
• Subscribe to comments version: 2.0.3
• PHP version: 4.1.2-7.woody5
• Operating system: Debian GNU/Linux 3.0

[davidhouse]

Thanks for the pointer.

[ryan]

(In [3489]) Make sure we have an array. Props David House. fixes #2344