Add supports argument to register_taxonomy

[paulwilde]

This patch adds the supports argument to register_taxonomy(). It allows custom taxonomies to opt out of having the slug and description fields.

I've had custom private taxonomies where the only field which would be set is "Name", so an enhancement like this would allow taxonomies be more lightweight for clients.

[paulwilde]

Remove testing code.

[paulwilde]

Remove testing code.

[knutsp]

+1 for description
-1 for slug

The slug field could be less prominent, and hidden by default, for all taxonomies, like it is for posts. (Show the slug n existing terms, but press a button to edit it.)

It should also be possible to remove support for description on builtin taxonomies.

[boonebgorges]

@rmccue You tagged this ticket rest-api, which suggests that in the context of the API, taxonomy supports would mean something more than hiding pieces of the admin UI. Can you say more about this?

The idea of hiding bits of the UI via supports seems OK to me, but if we're going to exploit a metaphor already in use by post types, we should make sure the functionality parallels that of post types as well - and I'm pretty sure that supports does more than hide admin UI for post types.

[rmccue]

@boonebgorges Indeed. We use the post type supports to automatically add/remove support for different parts of the response. For example, if the post type doesn't support title, we remove the title from the response (and the schema changes to reflect this).

Note that it's still technically possible to have titles on posts that don't support title, but you have to implement the UI and such yourself. Likewise, you can add it back to the API reasonably easily.

Our general assumption is that removing support for something indicates you're doing something special with it, and probably want a different output format for it. supports therefore is more of general indication of "I want WP to handle this".

[boonebgorges]

#35688 was marked as a duplicate.

[boonebgorges]

#35688 has some code that might be used if we want _supports() functions.

[pat@…]

Would love to see this make it in to an upcoming version. What needs to be done to make this happen?