register_taxonomy 'fields' hides pages in admin

[shortye]

Registering a custom taxonomy 'fields' hides the pages list in the admin since 4.2.1 update

$labels = array(

	'name' => _x( 'Markets', 'taxonomy general name', 'mytheme'),
	'singular_name' => _x( 'Market', 'taxonomy singular name', 'mytheme' ),
	'search_items' =>  __( 'Search Market', 'mytheme' ),
	'all_items' => __( 'All Markets', 'mytheme' ),
	'parent_item' => __( 'Parent Market', 'mytheme' ),
	'parent_item_colon' => __( 'Parent Market:', 'mytheme' ),
	'edit_item' => __( 'Edit Market', 'mytheme' ),
	'update_item' => __( 'Update Market', 'mytheme' ),
	'add_new_item' => __( 'Add New Market', 'mytheme' ),
	'new_item_name' => __( 'New Market', 'mytheme' ),
	'menu_name' => __( 'Markets', 'mytheme' )

);

register_taxonomy( 'fields', array('partner'), array(

	'hierarchical' => true,
	'labels' => $labels,
	'show_ui' => true,
	'query_var' => true,
	'public' => true,
	'rewrite' => array( 'slug' => 'markets' ),
));

Using any other taxonomy name works fine.
Tested on a clean install of 4.2.1 with twentyfifteen

[SergeyBiryukov]

Confirmed. Caused by $query['fields'] = 'id=>parent' in wp_edit_posts_query() (line 1042​).

'fields' is one of ​WP_Query parameters, I guess it should be added to the list of ​reserved terms.

[boonebgorges]

Replying to SergeyBiryukov:

Confirmed. Caused by $query['fields'] = 'id=>parent' in wp_edit_posts_query() (line 1042​).

'fields' is one of ​WP_Query parameters, I guess it should be added to the list of ​reserved terms.

Yeah, good find. I've added 'fields' to the list in the Codex. I guess we don't enforce these reserved terms anywhere; maybe that's a good project for the future. shortye - In the meantime, please use a taxonomy name other than 'fields' :)

[SergeyBiryukov]

Replying to boonebgorges:

I guess we don't enforce these reserved terms anywhere; maybe that's a good project for the future.

Related: #12929, #18263, #31154.