Block Editor: Hide the Custom Fields meta box option if that meta box has been removed.

Some plugins remove the Custom Fields meta box, particularly when they provide functionality that replaces it. The block editor would correctly not display this meta box in these circumstances, but it still showed the option to display or hide it.

Props pento, noisysocks.
Merges [43885] to trunk.
See #45282.
Built from https://develop.svn.wordpress.org/trunk@44244


git-svn-id: http://core.svn.wordpress.org/trunk@44074 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/edit-form-blocks.php

@@ -19,8 +19,9 @@ if ( ! defined( 'ABSPATH' ) ) {
  * @global WP_Post      $post
  * @global string       $title
  * @global array        $editor_styles
+ * @global array        $wp_meta_boxes
  */
-global $post_type, $post_type_object, $post, $title, $editor_styles;
+global $post_type, $post_type_object, $post, $title, $editor_styles, $wp_meta_boxes;
 
 if ( ! empty( $post_type_object ) ) {
 	$title = $post_type_object->labels->edit_item;
@@ -296,36 +297,6 @@ if ( $is_new_post && ! isset( $editor_settings['template'] ) && 'post' === $post
 	}
 }
 
-$init_script = <<<JS
-( function() {
-	window._wpLoadBlockEditor = new Promise( function( resolve ) {
-		wp.domReady( function() {
-			resolve( wp.editPost.initializeEditor( 'editor', "%s", %d, %s, %s ) );
-		} );
-	} );
-} )();
-JS;
-
-
-/**
- * Filters the settings to pass to the block editor.
- *
- * @since 5.0.0
- *
- * @param array   $editor_settings Default editor settings.
- * @param WP_Post $post            Post being edited.
- */
-$editor_settings = apply_filters( 'block_editor_settings', $editor_settings, $post );
-
-$script = sprintf(
-	$init_script,
-	$post->post_type,
-	$post->ID,
-	wp_json_encode( $editor_settings ),
-	wp_json_encode( $initial_edits )
-);
-wp_add_inline_script( 'wp-edit-post', $script );
-
 /**
  * Scripts
  */
@@ -358,6 +329,41 @@ do_action( 'enqueue_block_editor_assets' );
 require_once( ABSPATH . 'wp-admin/includes/meta-boxes.php' );
 register_and_do_post_meta_boxes( $post );
 
+// Check if the Custom Fields meta box has been removed at some point.
+$core_meta_boxes = $wp_meta_boxes[ $current_screen->id ]['normal']['core'];
+if ( ! isset( $core_meta_boxes['postcustom'] ) || ! $core_meta_boxes['postcustom'] ) {
+	unset( $editor_settings['enableCustomFields'] );
+}
+
+/**
+ * Filters the settings to pass to the block editor.
+ *
+ * @since 5.0.0
+ *
+ * @param array   $editor_settings Default editor settings.
+ * @param WP_Post $post            Post being edited.
+ */
+$editor_settings = apply_filters( 'block_editor_settings', $editor_settings, $post );
+
+$init_script = <<<JS
+( function() {
+	window._wpLoadBlockEditor = new Promise( function( resolve ) {
+		wp.domReady( function() {
+			resolve( wp.editPost.initializeEditor( 'editor', "%s", %d, %s, %s ) );
+		} );
+	} );
+} )();
+JS;
+
+$script = sprintf(
+	$init_script,
+	$post->post_type,
+	$post->ID,
+	wp_json_encode( $editor_settings ),
+	wp_json_encode( $initial_edits )
+);
+wp_add_inline_script( 'wp-edit-post', $script );
+
 require_once( ABSPATH . 'wp-admin/admin-header.php' );
 ?>
 

wp-admin/includes/meta-boxes.php

@@ -1463,7 +1463,11 @@ function register_and_do_post_meta_boxes( $post ) {
 	}
 
 	if ( post_type_supports( $post_type, 'custom-fields' ) ) {
-		add_meta_box( 'postcustom', __( 'Custom Fields' ), 'post_custom_meta_box', null, 'normal', 'core', array( '__back_compat_meta_box' => true ) );
+		$args = array(
+			'__back_compat_meta_box'             => ! (bool) get_user_meta( get_current_user_id(), 'enable_custom_fields', true ),
+			'__block_editor_compatible_meta_box' => true,
+		);
+		add_meta_box( 'postcustom', __( 'Custom Fields' ), 'post_custom_meta_box', null, 'normal', 'core', $args );
 	}
 
 	/**

wp-admin/includes/template.php

@@ -1161,7 +1161,8 @@ function do_meta_boxes( $screen, $context, $object ) {
 					}
 
 					$i++;
-					$hidden_class = in_array( $box['id'], $hidden ) ? ' hide-if-js' : '';
+					// get_hidden_meta_boxes() doesn't apply in the block editor.
+					$hidden_class = ( ! $screen->is_block_editor() && in_array( $box['id'], $hidden ) ) ? ' hide-if-js' : '';
 					echo '<div id="' . $box['id'] . '" class="postbox ' . postbox_classes( $box['id'], $page ) . $hidden_class . '" ' . '>' . "\n";
 					if ( 'dashboard_browser_nag' != $box['id'] ) {
 						$widget_title = $box['title'];

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44243';
+$wp_version = '5.1-alpha-44244';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.