Customize: Custom post types cannot be used in starter content

[westonruter]

As ​reported by @tiagonoronha:

hi! I noticed that custom posts types cannot be used in Starter Content. CPTs are registered in the init hook, way after starter content is loaded in after_theme_setup. Is this a known issue? thanks!

​and:

Hi! Well, they literally cannot be used in any way. Adding a post of a CPT in starter content gives me a warning in the customizer. I’m testing this with WooCommerce that registers the CPTs on init. This is not a problem with the default post types because they get registered two times, in wp-settings.php and then again on the init hook.

[westonruter]

The problem is that \WP_Customize_Nav_Menus::insert_auto_draft_post() was doing a post_type_exists() check and bailing. It's clear that for the purposes of this API method there needn't be a post type existence check, especially in the case of importing starter content. Note that post_type_exists() check is still present in WP_Customize_Nav_Menus::ajax_insert_auto_draft_post() and so the check was actually redundant.

[westonruter]

A fix also was needed in Customize Posts to prevent a warning from being triggered: ​https://github.com/xwp/wp-customize-posts/pull/340

[tiagonoronha]

@westonruter tested, works perfectly! :)

[westonruter]

In 39924:

Customize: Allow custom post types to be used in starter content.

Changes WP_Customize_Nav_Menus::insert_auto_draft_post() so it can be invoked for a post_type that is not registered (yet).

See #38615, #38114.
Fixes #39610.

[westonruter]

Re-opening for 4.7.2

[dd32]

In 40098:

Customize: Allow custom post types to be used in starter content.

Changes WP_Customize_Nav_Menus::insert_auto_draft_post() so it can be invoked for a post_type that is not registered (yet).

Props westonruter.
Merges [39924] to the 4.7 branch.
See #38615, #38114.
Fixes #39610.