Add options to a Wordpress plugin Custom Post Type via child theme functions.php

Question

I'm using Uncode theme for a site. It has a core custom post type called 'portfolio'.

I need to add an option to this CPT so that it shares the tags with regular posts.

I have found the file in the theme core where the CPT is registered and added the following and it works:

'taxonomies' => array('portfolio_category', 'post_tag')

However, as editing core files is a big no no, I'm wondering if there is a way of doing this through my own functions file so it is future proof?

Answer 1

EDIT : It's apparent that I've misunderstood!

Looks like register_taxonomy_for_object_type is what you're after.

The WP Codex has this to say:

register_taxonomy_for_object_type()

Add a registered Taxonomy to a registered Post Type.

register_taxonomy_for_object_type( 'post_tag', 'portfolio' );

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Original answer:

From the WP Codex :

register_post_type()

Create or modify a post type. register_post_type should only be invoked through the 'init' action. It will not work if called before 'init' , and aspects of the newly created or modified post type will work incorrectly if called later.

_{(addtl. emphasis mine)}

This being the case, you could create a function

function igloobob_portfolio_cpt_mod() {
    register_post_type('portfolio', $args);
}
add_action('init', 'igloobob_portfolio_cpt_mod', 999);

where $args basically duplicate's the Uncode theme's arguments to register_post_type , save for your modification. The 999 priority arg is to ensure that it executes after the parent theme has already registered the post type.