TypeError: Cannot read property 'prefix' of null

[petenelson]

When adding a new custom post type, upon hitting "Save Draft", the "The editor has encountered an unexpected error." message appears, and this is the error message. This had been working in 4.5

Editing an existing custom post type shows the error immediately.

TypeError: Cannot read property 'prefix' of null
    at http://devsite.local/wp-content/plugins/gutenberg/build/edit-post/index.js?ver=1543608571:12:54832
    at mountIndeterminateComponent (http://devsite.local/wp-content/plugins/gutenberg/vendor/react-dom.60482cc7.js:14687:13)
    at beginWork (http://devsite.local/wp-content/plugins/gutenberg/vendor/react-dom.60482cc7.js:15187:16)
    at performUnitOfWork (http://devsite.local/wp-content/plugins/gutenberg/vendor/react-dom.60482cc7.js:17944:12)
    at workLoop (http://devsite.local/wp-content/plugins/gutenberg/vendor/react-dom.60482cc7.js:17984:24)
    at renderRoot (http://devsite.local/wp-content/plugins/gutenberg/vendor/react-dom.60482cc7.js:18070:7)
    at performWorkOnRoot (http://devsite.local/wp-content/plugins/gutenberg/vendor/react-dom.60482cc7.js:18961:7)
    at performWork (http://devsite.local/wp-content/plugins/gutenberg/vendor/react-dom.60482cc7.js:18873:7)
    at performSyncWork (http://devsite.local/wp-content/plugins/gutenberg/vendor/react-dom.60482cc7.js:18847:3)
    at requestWork (http://devsite.local/wp-content/plugins/gutenberg/vendor/react-dom.60482cc7.js:18716:5)

Additional context

• Gutenberg 4.6.0

[swissspidy]

How did you register the custom post type? Could you perhaps share that code here?

The only place where I see prefix in the edit-post package is related to permalinks.

[petenelson]

Here's the args for the post type.

$args = [
	'labels'              => $labels,
	'exclude_from_search' => true,
	'publicly_queryable'  => true,
	'show_in_nav_menus'   => false,
	'show_ui'             => true,
	'show_in_menu'        => true,
	'menu_position'       => 2,
	'menu_icon'           => 'dashicons-admin-home',
	'has_archive'         => false,
	'supports'            => [
		'title',
		'editor',
		'revisions',
	],
	'rewrite'             => false,
	'capability_type'     => get_post_type_name(),
	'map_meta_cap'        => true,

	// Needs to be true for Gutenberg.
	'show_in_rest'        => true,
];

$args = apply_filters( get_post_type_name() . '_args', $args );

\register_post_type( get_post_type_name(), $args );

[joshuafredrickson]

This occurred for me in 4.6.1 with custom post types with 'public' => false. When I change it to true, the error goes away.

When set to false:

And in the console:

TypeError: Cannot read property 'prefix' of null
    at index.js?ver=1544119766:12
    at ph (react-dom.min.713f0afa.js:97)
    at eg (react-dom.min.713f0afa.js:125)
    at fg (react-dom.min.713f0afa.js:126)
    at wc (react-dom.min.713f0afa.js:138)
    at fa (react-dom.min.713f0afa.js:137)
    at gg (react-dom.min.713f0afa.js:135)
    at Ca (react-dom.min.713f0afa.js:133)
    at Object.enqueueSetState (react-dom.min.713f0afa.js:191)
    at r.q.setState (react.min.1b974caa.js:20)

[jorgefilipecosta]

Maybe related: #12677

[apermo]

I have the same issue.

With Gutenberg 4.5.1 it works fine. Updating to GB 4.6.x breaks the code, disabled nearly all plugins besides Gutenberg and the one registering my posttype.

$args = array(
			'label'               => __( 'Portal Page', 'r24-portal-pages' ),
			'description'         => __( 'Portal Page', 'r24-portal-pages' ),
			'labels'              => $labels,
			'supports'            => array( 'title', 'editor', 'custom-fields' ),
			'taxonomies'          => array( 'node_tax' ),
			'hierarchical'        => false,
			'public'              => false,
			'show_ui'             => true,
			'show_in_menu'        => true,
			'menu_position'       => 15,
			'menu_icon'           => 'dashicons-schedule',
			'show_in_admin_bar'   => false,
			'show_in_nav_menus'   => false,
			'can_export'          => true,
			'has_archive'         => false,
			'exclude_from_search' => true,
			'publicly_queryable'  => current_user_can( 'edit_posts' ),
			'rewrite'             => false,
			'capability_type'     => 'page',
			'show_in_rest'        => true,
		);
register_post_type( 'portal_page', $args );

This is my code for the CPT

Edit:
Changing publicly_queryableto hardcoded true does not fix this problem.

Changing publicfrom false to true will restore the editor and fix the problem.