wp_list_filter Notice

[wpsmith]

If someone wanted to add an argument for easy filtering on a taxonomy and then used get_taxonomies to query that non-standard key, it generates notices.

E.g., Given labels,

$args = array( 'mycustomkey' => true, 'hierarchical' => 0, 'rewrite' => array( 'slug' ), );
register_taxonomy( 'my_taxonomy', array( 'my_post_type' ), $args);

Then later, if I used:

 get_taxonomies( array( 'mycustomkey' => true ) );

it generates:

Notice: Undefined index: mycustomkey in C:\xampp\htdocs\www\sandbox\wp-includes\functions.php on line 2499.

This is a simple fix:

if ( isset($to_match[ $m_key ]) && $m_value == $to_match[ $m_key ] )

I was able to reproduce this bug very easily.

I have also reviewed and tested this patch with 3.4, and this looks good.

Looks good at a glance. Some thoughts and housekeeping:

• Let's use array_key_exists() here instead. isset() will return false if the value is null, and that may not be expected behavior here.

• If we had kept isset(), isset($to_match[ $m_key ]) && would be isset( $to_match[ $m_key ] ) && per our coding standards.

• Please diff from the root of WordPress, rather than from within wp-includes. This will provide for a patch path of wp-includes/functions.php, rather than just functions.php. There happens to be only one functions.php file in core (outside of default themes), so when prompted someone applying the patch could guess, but there are three post.php files.

• Some tests here would be cool. They could go into TestListFilter. If you run the test suite with the -d flag, it forces WP_DEBUG, and thus you can write a test that could normally generate a notice. Be sure to test the NULL case :-)

Replying to nacin:

• Some tests here would be cool. They could go into TestListFilter. If you run the test suite with the -d flag, it forces WP_DEBUG, and thus you can write a test that could normally generate a notice. Be sure to test the NULL case :-)

Thanks Nacin! Any tips/links on how to do the test or run the test suite?

Replying to wpsmith:

Any tips/links on how to do the test or run the test suite?

​http://codex.wordpress.org/Automated_Testing

First pass unit test

Attached the first attempt at a unit test. I'm sure it could be improved upon.

It doesn't rely on the user passing "-d" in, and will force E_NOTICE on to capture the notice message, since that's the symptom we're testing.

In [21184]:

Check if array key exists in wp_list_filter(). props wpsmith. fixes #20929.