Docs on registering CPT on plugin activation hook

Hello, I’m trying to understand the plugin handbook example on registering a custom post type inside the activation hook:

/**
 * Register the "book" custom post type
 */
function pluginprefix_setup_post_type() {
    register_post_type( 'book', ['public' => true ] ); 
} 
add_action( 'init', 'pluginprefix_setup_post_type' );
 
 
/**
 * Activate the plugin.
 */
function pluginprefix_activate() { 
    // Trigger our function that registers the custom post type plugin.
    pluginprefix_setup_post_type(); 
    // Clear the permalinks after the post type has been registered.
    flush_rewrite_rules(); 
}
register_activation_hook( __FILE__, 'pluginprefix_activate' );

Why is the pluginprefix_activate function calling pluginprefix_setup_post_type if this is already being added to init with the add_action function?

The example works the same if the function is not called inside pluginprefix_activate so this is confusing me. I understand that is important to call flush_rewrite_rules on activation but not pluginprefix_setup_post_type

Any ideas?
Thank you.

• This topic was modified 3 years, 10 months ago by Daniel P..