Post type object does not always have taxonomies populated correctly.

[desrosj]

Using get_post_type_object(), I found that the 'taxonomies' array was not always accurate with all added taxonomies.

For example, if you do the following, get_post_type_object( 'post' ), there should be 'category', 'post_tag', and 'post_format' values (on a fresh install of WordPress) in that array.

The only time taxonomies seem to make it into there is when you define taxonomies in the 'taxonomies' argument when using register_post_type().

The attached patch fixes this issue. However, some additional thought may need to be given. Was this post type object property meant to be used like that? Do we only populate it with public taxonomies? Do we add a parameter to register_taxonomy() to control if it gets listed there?

[desrosj]

Patch adding taxonomies to post type objects when using register_taxonomy().

[nacin]

The 'taxonomies' property is actually only for registration. We probably should unset it after we call register_taxonomy_for_object_type() internally.

Post types associated with a taxonomy are stored within the taxonomy object. You can get them by doing this:

$object_types = get_taxonomy( $taxonomy )->object_types;
// object types could include 'user', 'link', or something arbitrary
$object_types = array_filter( $object_types, 'post_type_exists' );

Eventually, post type objects and taxonomy objects will be proper objects (no timeline for this — we have a long way to go before this makes sense and the picture is clear), at which point helper methods may make this easier, and would allow for live-updating at any given time.

[boonebgorges]

Closing based on nacin's comment above.