cap fixes in _wp_insert_post

[nprasath002]

The patch validates 'publish_post' with post_ID to check whether the user is allowed to publish an already existing post

[ryan]

In [20568]:

Check the publish_post cap when publishing an already existing post.

Props nprasath002
Fixes #20474

[nacin]

There isn't a publish_post cap...

[scribu]

The magic of meta caps: current_user_can( 'publish_post', $post_data[ 'ID' ] ) )

That should work with all post types, right?

[ryan]

Well hell I thought we added that.

[ryan]

get_post_type_capabilities() would also need an update. Probably not worth it for 3.4, but I think I'd like to finally do publish_post in 3.5 since this happens all the time.

[ryan]

In [20576]:

Revert [20568] until a publish_post cap is introduced. see #20474

[ryan]

There are edit_post/edit_posts checks above this block. I think all cap bases are covered.