Editor: Fix custom sources backwards compatibility for the pages post type.

[epiqueras]

Fixes #17767

Description

This PR fixes the custom sources backwards compatibility filter's hook to take into account post types other than post.

How has this been tested?

It was verified that adding blocks with meta sources to pages no longer crashes the editor and an e2e test was added to avoid regressions.

Types of Changes

Bug Fix: Meta sources no longer crash the editor if the edited post is not of post type post.

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.

[youknowriad]

getCurrentPostType selector maybe?

[epiqueras]

Sure, we'll need to change it later, but it's better for performance now.

[youknowriad]

This makes sense to me. I didn't test but I trust the e2e test here.

[luuptekman]

Came into this issue via #17767.

I'm still experiencing this issue with custom post type (in my case I have created a new post type experiences). When adding a block in custom post edit screen this happens Cannot read property '_my_meta_id' of undefined.

When adding the block in posts/pages, everything is ok. This is the block plugin I'm using to reproduce the issue with WP 5.3.2. https://github.com/luuptek/bokun-wp

[epiqueras]

When adding a block in custom post edit screen this happens Cannot read property '_my_meta_id' of undefined.
When adding the block in posts/pages, everything is ok.

Sounds like the core-data store is not bootstrapped correctly. Is getEntityRecord being called for the relevant post before loading the editor?

[luuptekman]

How can I check that?

[epiqueras]

Where is the code for the custom post edit screen?

[luuptekman]

Where is the code for the custom post edit screen?

Gutenberg related stuff in here: https://github.com/luuptek/bokun-wp/blob/master/src/bokun-product/bokun-product.js ==> _bokun_wp_bokun_id is what it's complaining about...

Meta data is registered via register_post_meta in main plugin file: https://github.com/luuptek/bokun-wp/blob/master/bokun-wp.php

Custom post is added in theme , example via this:

function book_setup_post_type() {
	$args = array(
		'public'    => true,
		'label'     => __( 'Books', 'textdomain' ),
		'menu_icon' => 'dashicons-book',
		'show_in_rest' => true,
	);
	register_post_type( 'book', $args );
}
add_action( 'init', 'book_setup_post_type' );

[epiqueras]

When adding a block in custom post edit screen this happens Cannot read property '_my_meta_id' of undefined.

Where is that custom post edit screen?

[luuptekman]

When adding a block in custom post edit screen this happens Cannot read property '_my_meta_id' of undefined.

Where is that custom post edit screen?

Depends on custom post definition...in example above it would be in Books => Add new

[epiqueras]

Sounds like your post type is missing custom-fields support.

https://developer.wordpress.org/reference/functions/register_post_type/

https://developer.wordpress.org/reference/functions/add_post_type_support/

[luuptekman]

Big thanks for pointing that! So custom post need to support custom-fields ==> will work then 👍

[epiqueras]

I'm glad I could help! 😄