Post Content: Fix display of block support styles (#66003)

Co-authored-by: aaronrobertshaw <[email protected]>
Co-authored-by: ntsekouras <[email protected]>
Co-authored-by: andrewserong <[email protected]>
Co-authored-by: ramonjd <[email protected]>
Co-authored-by: peterwilsoncc <[email protected]>
Co-authored-by: jasmussen <[email protected]>
Co-authored-by: carolinan <[email protected]>
Co-authored-by: ndiego <[email protected]>
Co-authored-by: colorful-tones <[email protected]>

packages/block-library/src/post-content/edit.js

@@ -8,19 +8,24 @@ import {
 	RecursionProvider,
 	useHasRecursion,
 	Warning,
+	__experimentalUseBlockPreview as useBlockPreview,
 } from '@wordpress/block-editor';
+import { parse } from '@wordpress/blocks';
 import {
 	useEntityProp,
 	useEntityBlockEditor,
 	store as coreStore,
 } from '@wordpress/core-data';
 import { useSelect } from '@wordpress/data';
+import { useMemo } from '@wordpress/element';
+
 /**
  * Internal dependencies
  */
 import { useCanEditEntity } from '../utils/hooks';
 
 function ReadOnlyContent( {
+	parentLayout,
 	layoutClassNames,
 	userCanEdit,
 	postType,
@@ -33,7 +38,28 @@ function ReadOnlyContent( {
 		postId
 	);
 	const blockProps = useBlockProps( { className: layoutClassNames } );
-	return content?.protected && ! userCanEdit ? (
+	const blocks = useMemo( () => {
+		return content?.raw ? parse( content.raw ) : [];
+	}, [ content?.raw ] );
+	const blockPreviewProps = useBlockPreview( {
+		blocks,
+		props: blockProps,
+		layout: parentLayout,
+	} );
+
+	if ( userCanEdit ) {
+		/*
+		 * Rendering the block preview using the raw content blocks allows for
+		 * block support styles to be generated and applied by the editor.
+		 *
+		 * The preview using the raw blocks can only be presented to users with
+		 * edit permissions for the post to prevent potential exposure of private
+		 * block content.
+		 */
+		return <div { ...blockPreviewProps }></div>;
+	}
+
+	return content?.protected ? (
 		<div { ...blockProps }>
 			<Warning>{ __( 'This content is password protected.' ) }</Warning>
 		</div>
@@ -96,6 +122,7 @@ function Content( props ) {
 		<EditableContent { ...props } />
 	) : (
 		<ReadOnlyContent
+			parentLayout={ props.parentLayout }
 			layoutClassNames={ layoutClassNames }
 			userCanEdit={ userCanEdit }
 			postType={ postType }
@@ -141,6 +168,7 @@ function RecursionError() {
 export default function PostContentEdit( {
 	context,
 	__unstableLayoutClassNames: layoutClassNames,
+	__unstableParentLayout: parentLayout,
 } ) {
 	const { postId: contextPostId, postType: contextPostType } = context;
 	const hasAlreadyRendered = useHasRecursion( contextPostId );
@@ -154,6 +182,7 @@ export default function PostContentEdit( {
 			{ contextPostId && contextPostType ? (
 				<Content
 					context={ context }
+					parentLayout={ parentLayout }
 					layoutClassNames={ layoutClassNames }
 				/>
 			) : (