Block Themes: Add Infrastructure

src/wp-includes/blocks.php

@@ -1154,6 +1154,8 @@ function build_query_vars_from_query_block( $block, $page ) {
  *
  * It's used in QueryPaginationNext and QueryPaginationPrevious blocks.
  *
+ * @since 5.9.0
+ *
  * @param WP_Block $block   Block instance.
  * @param boolean  $is_next Flag for hanlding `next/previous` blocks.
  *

src/wp-includes/blocks/index.php

@@ -37,6 +37,7 @@
 require ABSPATH . WPINC . '/blocks/site-title.php';
 require ABSPATH . WPINC . '/blocks/social-link.php';
 require ABSPATH . WPINC . '/blocks/tag-cloud.php';
+require ABSPATH . WPINC . '/blocks/template-part.php';
 
 /**
  * Registers core block types using metadata files.

src/wp-includes/blocks/template-part.php

@@ -0,0 +1,155 @@
+<?php
+/**
+ * Server-side rendering of the `core/template-part` block.
+ *
+ * @package WordPress
+ */
+
+/**
+ * Renders the `core/template-part` block on the server.
+ *
+ * @param array $attributes The block attributes.
+ *
+ * @return string The render.
+ */
+function render_block_core_template_part( $attributes ) {
+	static $seen_ids = array();
+
+	$template_part_id = null;
+	$content          = null;
+	$area             = WP_TEMPLATE_PART_AREA_UNCATEGORIZED;
+
+	if (
+		isset( $attributes['slug'] ) &&
+		isset( $attributes['theme'] ) &&
+		wp_get_theme()->get_stylesheet() === $attributes['theme']
+	) {
+		$template_part_id    = $attributes['theme'] . '//' . $attributes['slug'];
+		$template_part_query = new WP_Query(
+			array(
+				'post_type'      => 'wp_template_part',
+				'post_status'    => 'publish',
+				'post_name__in'  => array( $attributes['slug'] ),
+				'tax_query'      => array(
+					array(
+						'taxonomy' => 'wp_theme',
+						'field'    => 'slug',
+						'terms'    => $attributes['theme'],
+					),
+				),
+				'posts_per_page' => 1,
+				'no_found_rows'  => true,
+			)
+		);
+		$template_part_post  = $template_part_query->have_posts() ? $template_part_query->next_post() : null;
+		if ( $template_part_post ) {
+			// A published post might already exist if this template part was customized elsewhere
+			// or if it's part of a customized template.
+			$content    = $template_part_post->post_content;
+			$area_terms = get_the_terms( $template_part_post, 'wp_template_part_area' );
+			if ( ! is_wp_error( $area_terms ) && false !== $area_terms ) {
+				$area = $area_terms[0]->name;
+			}
+		} else {
+			// Else, if the template part was provided by the active theme,
+			// render the corresponding file content.
+			$template_part_file_path = get_theme_file_path( '/block-template-parts/' . $attributes['slug'] . '.html' );
+			if ( 0 === validate_file( $attributes['slug'] ) && file_exists( $template_part_file_path ) ) {
+				$content = _inject_theme_attribute_in_block_template_content( file_get_contents( $template_part_file_path ) );
+			}
+		}
+	}
+
+	if ( is_null( $content ) && is_user_logged_in() ) {
+		if ( ! isset( $attributes['slug'] ) ) {
+			// If there is no slug this is a placeholder and we dont want to return any message.
+			return;
+		}
+		return sprintf(
+			/* translators: %s: Template part slug. */
+			__( 'Template part has been deleted or is unavailable: %s' ),
+			$attributes['slug']
+		);
+	}
+
+	if ( isset( $seen_ids[ $template_part_id ] ) ) {
+		// WP_DEBUG_DISPLAY must only be honored when WP_DEBUG. This precedent
+		// is set in `wp_debug_mode()`.
+		$is_debug = defined( 'WP_DEBUG' ) && WP_DEBUG &&
+			defined( 'WP_DEBUG_DISPLAY' ) && WP_DEBUG_DISPLAY;
+
+		return $is_debug ?
+			// translators: Visible only in the front end, this warning takes the place of a faulty block.
+			__( '[block rendering halted]' ) :
+			'';
+	}
+
+	// Run through the actions that are typically taken on the_content.
+	$seen_ids[ $template_part_id ] = true;
+	$content                       = do_blocks( $content );
+	unset( $seen_ids[ $template_part_id ] );
+	$content = wptexturize( $content );
+	$content = convert_smilies( $content );
+	$content = shortcode_unautop( $content );
+	$content = wp_filter_content_tags( $content );
+	$content = do_shortcode( $content );
+
+	// Handle embeds for block template parts.
+	global $wp_embed;
+	$content = $wp_embed->autoembed( $content );
+
+	if ( empty( $attributes['tagName'] ) ) {
+		$defined_areas = get_allowed_block_template_part_areas();
+		$area_tag      = 'div';
+		foreach ( $defined_areas as $defined_area ) {
+			if ( $defined_area['area'] === $area && isset( $defined_area['area_tag'] ) ) {
+				$area_tag = $defined_area['area_tag'];
+			}
+		}
+		$html_tag = $area_tag;
+	} else {
+		$html_tag = esc_attr( $attributes['tagName'] );
+	}
+	$wrapper_attributes = get_block_wrapper_attributes();
+
+	return "<$html_tag $wrapper_attributes>" . str_replace( ']]>', ']]&gt;', $content ) . "</$html_tag>";
+}
+
+/**
+ * Returns an array of variation objects for the template part block.
+ *
+ * @return array Array containing the block variation objects.
+ */
+function build_template_part_block_variations() {
+	$variations    = array();
+	$defined_areas = get_allowed_block_template_part_areas();
+	foreach ( $defined_areas as $area ) {
+		if ( 'uncategorized' !== $area['area'] ) {
+			$variations[] = array(
+				'name'        => $area['area'],
+				'title'       => $area['label'],
+				'description' => $area['description'],
+				'attributes'  => array(
+					'area' => $area['area'],
+				),
+				'scope'       => array( 'inserter' ),
+				'icon'        => $area['icon'],
+			);
+		}
+	}
+	return $variations;
+}
+
+/**
+ * Registers the `core/template-part` block on the server.
+ */
+function register_block_core_template_part() {
+	register_block_type_from_metadata(
+		__DIR__ . '/template-part',
+		array(
+			'render_callback' => 'render_block_core_template_part',
+			'variations'      => build_template_part_block_variations(),
+		)
+	);
+}
+add_action( 'init', 'register_block_core_template_part' );

src/wp-includes/blocks/template-part/block.json

@@ -0,0 +1,35 @@
+{
+	"apiVersion": 2,
+	"name": "core/template-part",
+	"title": "Template Part",
+	"category": "theme",
+	"description": "Edit the different global regions of your site, like the header, footer, sidebar, or create your own.",
+	"textdomain": "default",
+	"attributes": {
+		"slug": {
+			"type": "string"
+		},
+		"theme": {
+			"type": "string"
+		},
+		"tagName": {
+			"type": "string"
+		},
+		"area": {
+			"type": "string"
+		}
+	},
+	"supports": {
+		"align": true,
+		"html": false,
+		"color": {
+			"gradients": true,
+			"link": true
+		},
+		"spacing": {
+			"padding": true
+		},
+		"__experimentalLayout": true
+	},
+	"editorStyle": "wp-block-template-part-editor"
+}

src/wp-includes/class-wp-block-template.php

@@ -100,4 +100,13 @@ class WP_Block_Template {
 	 * @var boolean
 	 */
 	public $has_theme_file;
+
+	/**
+	 * Whether a template is a custom template.
+	 *
+	 * @since 5.9.0
+	 *
+	 * @var boolean
+	 */
+	public $is_custom = true;
 }

src/wp-includes/class-wp-theme-json.php

@@ -601,7 +601,7 @@ public function get_stylesheet( $types = array( 'variables', 'styles', 'presets'
 	 */
 	public function get_custom_templates() {
 		$custom_templates = array();
-		if ( ! isset( $this->theme_json['customTemplates'] ) ) {
+		if ( ! isset( $this->theme_json['customTemplates'] ) || ! is_array( $this->theme_json['customTemplates'] ) ) {
 			return $custom_templates;
 		}
 
@@ -625,7 +625,7 @@ public function get_custom_templates() {
 	 */
 	public function get_template_parts() {
 		$template_parts = array();
-		if ( ! isset( $this->theme_json['templateParts'] ) ) {
+		if ( ! isset( $this->theme_json['templateParts'] ) || ! is_array( $this->theme_json['templateParts'] ) ) {
 			return $template_parts;
 		}
 

src/wp-includes/default-filters.php

@@ -664,6 +664,7 @@
 // Block Templates CPT and Rendering
 add_filter( 'render_block_context', '_block_template_render_without_post_block_context' );
 add_filter( 'pre_wp_unique_post_slug', 'wp_filter_wp_template_unique_post_slug', 10, 5 );
+add_action( 'save_post_wp_template_part', 'wp_set_unique_slug_on_create_template_part' );
 add_action( 'wp_footer', 'the_block_template_skip_link' );
 add_action( 'setup_theme', 'wp_enable_block_templates' );
 

src/wp-includes/post.php

@@ -365,6 +365,64 @@ function create_initial_post_types() {
 		)
 	);
 
+	register_post_type(
+		'wp_template_part',
+		array(
+			'labels'                => array(
+				'name'                  => __( 'Template Parts' ),
+				'singular_name'         => __( 'Template Part' ),
+				'add_new'               => _x( 'Add New', 'Template Part' ),
+				'add_new_item'          => __( 'Add New Template Part' ),
+				'new_item'              => __( 'New Template Part' ),
+				'edit_item'             => __( 'Edit Template Part' ),
+				'view_item'             => __( 'View Template Part' ),
+				'all_items'             => __( 'All Template Parts' ),
+				'search_items'          => __( 'Search Template Parts' ),
+				'parent_item_colon'     => __( 'Parent Template Part:' ),
+				'not_found'             => __( 'No template parts found.' ),
+				'not_found_in_trash'    => __( 'No template parts found in Trash.' ),
+				'archives'              => __( 'Template part archives' ),
+				'insert_into_item'      => __( 'Insert into template part' ),
+				'uploaded_to_this_item' => __( 'Uploaded to this template part' ),
+				'filter_items_list'     => __( 'Filter template parts list' ),
+				'items_list_navigation' => __( 'Template parts list navigation' ),
+				'items_list'            => __( 'Template parts list' ),
+			),
+			'description'           => __( 'Template parts to include in your templates.' ),
+			'public'                => false,
+			'_builtin'              => true, /* internal use only. don't use this when registering your own post type. */
+			'has_archive'           => false,
+			'show_ui'               => false,
+			'show_in_menu'          => false,
+			'show_in_rest'          => true,
+			'rewrite'               => false,
+			'rest_base'             => 'template-parts',
+			'rest_controller_class' => 'WP_REST_Templates_Controller',
+			'map_meta_cap'          => true,
+			'capabilities'          => array(
+				'create_posts'           => 'edit_theme_options',
+				'delete_posts'           => 'edit_theme_options',
+				'delete_others_posts'    => 'edit_theme_options',
+				'delete_private_posts'   => 'edit_theme_options',
+				'delete_published_posts' => 'edit_theme_options',
+				'edit_posts'             => 'edit_theme_options',
+				'edit_others_posts'      => 'edit_theme_options',
+				'edit_private_posts'     => 'edit_theme_options',
+				'edit_published_posts'   => 'edit_theme_options',
+				'publish_posts'          => 'edit_theme_options',
+				'read'                   => 'edit_theme_options',
+				'read_private_posts'     => 'edit_theme_options',
+			),
+			'supports'              => array(
+				'title',
+				'slug',
+				'excerpt',
+				'editor',
+				'revisions',
+			),
+		)
+	);
+
 	register_post_type(
 		'wp_global_styles',
 		array(