Backport: Allow template duplication + concept of active templates

src/wp-admin/site-editor.php

@@ -182,6 +182,7 @@ static function ( $classes ) {
 	array( rest_get_route_for_post_type_items( 'attachment' ), 'OPTIONS' ),
 	array( rest_get_route_for_post_type_items( 'page' ), 'OPTIONS' ),
 	'/wp/v2/types?context=view',
+	'/wp/v2/wp_registered_template?context=edit',
 	'/wp/v2/types/wp_template?context=edit',
 	'/wp/v2/types/wp_template_part?context=edit',
 	'/wp/v2/templates?context=edit&per_page=-1',
@@ -244,7 +245,9 @@ static function ( $classes ) {
 			);
 		}
 	}
-} else {
+} elseif ( isset( $_GET['p'] ) && '/' !== $_GET['p'] ) {
+	// Only prefetch for the root. If we preload it for all pages and it's not
+	// used it won't be possible to invalidate.
 	$preload_paths[] = '/wp/v2/templates/lookup?slug=front-page';
 	$preload_paths[] = '/wp/v2/templates/lookup?slug=home';
 }

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

@@ -1074,6 +1074,46 @@ function _build_block_template_result_from_post( $post ) {
 	return $template;
 }
 
+function get_registered_block_templates( $query ) {
+	$template_files = _get_block_templates_files( 'wp_template', $query );
+	$query_result   = array();
+
+	// _get_block_templates_files seems broken, it does not obey the query.
+	if ( isset( $query['slug__in'] ) && is_array( $query['slug__in'] ) ) {
+		$template_files = array_filter(
+			$template_files,
+			function ( $template_file ) use ( $query ) {
+				return in_array( $template_file['slug'], $query['slug__in'], true );
+			}
+		);
+	}
+
+	foreach ( $template_files as $template_file ) {
+		$query_result[] = _build_block_template_result_from_file( $template_file, 'wp_template' );
+	}
+
+	// Add templates registered through the template registry. Filtering out the
+	// ones which have a theme file.
+	$registered_templates          = WP_Block_Templates_Registry::get_instance()->get_by_query( $query );
+	$matching_registered_templates = array_filter(
+		$registered_templates,
+		function ( $registered_template ) use ( $template_files ) {
+			foreach ( $template_files as $template_file ) {
+				if ( $template_file['slug'] === $registered_template->slug ) {
+					return false;
+				}
+			}
+			return true;
+		}
+	);
+
+	$query_result = array_merge( $query_result, $matching_registered_templates );
+
+	// Templates added by PHP filter also count as registered templates.
+	/** This filter is documented in wp-includes/block-template-utils.php */
+	return apply_filters( 'get_block_templates', $query_result, $query, 'wp_template' );
+}
+
 /**
  * Retrieves a list of unified template objects based on a query.
  *
@@ -1152,6 +1192,8 @@ function get_block_templates( $query = array(), $template_type = 'wp_template' )
 		$wp_query_args['post_status'] = 'publish';
 	}
 
+	$active_templates = get_option( 'active_templates', array() );
+
 	$template_query = new WP_Query( $wp_query_args );
 	$query_result   = array();
 	foreach ( $template_query->posts as $post ) {
@@ -1173,7 +1215,14 @@ function get_block_templates( $query = array(), $template_type = 'wp_template' )
 			continue;
 		}
 
-		$query_result[] = $template;
+		if ( $template->is_custom || isset( $query['wp_id'] ) ) {
+			// Custom templates don't need to be activated, leave them be.
+			// Also don't filter out templates when querying by wp_id.
+			$query_result[] = $template;
+		} elseif ( isset( $active_templates[ $template->slug ] ) && $active_templates[ $template->slug ] === $post->ID ) {
+			// Only include active templates.
+			$query_result[] = $template;
+		}
 	}
 
 	if ( ! isset( $query['wp_id'] ) ) {
@@ -1296,7 +1345,25 @@ function get_block_template( $id, $template_type = 'wp_template' ) {
 		return null;
 	}
 	list( $theme, $slug ) = $parts;
-	$wp_query_args        = array(
+
+	$active_templates = get_option( 'active_templates', array() );
+
+	if ( ! empty( $active_templates[ $slug ] ) ) {
+		if ( is_int( $active_templates[ $slug ] ) ) {
+			$post = get_post( $active_templates[ $slug ] );
+			if ( $post && 'publish' === $post->post_status ) {
+				$template = _build_block_template_result_from_post( $post );
+
+				if ( ! is_wp_error( $template ) && $theme === $template->theme ) {
+					return $template;
+				}
+			}
+		} elseif ( false === $active_templates[ $slug ] ) {
+			return null;
+		}
+	}
+
+	$wp_query_args  = array(
 		'post_name__in'  => array( $slug ),
 		'post_type'      => $template_type,
 		'post_status'    => array( 'auto-draft', 'draft', 'publish', 'trash' ),
@@ -1310,12 +1377,18 @@ function get_block_template( $id, $template_type = 'wp_template' ) {
 			),
 		),
 	);
-	$template_query       = new WP_Query( $wp_query_args );
-	$posts                = $template_query->posts;
+	$template_query = new WP_Query( $wp_query_args );
+	$posts          = $template_query->posts;
 
 	if ( count( $posts ) > 0 ) {
 		$template = _build_block_template_result_from_post( $posts[0] );
 
+		// Custom templates don't need to be activated, so if it's a custom
+		// template, return it.
+		if ( ! is_wp_error( $template ) && $template->is_custom ) {
+			return $template;
+		}
+
 		if ( ! is_wp_error( $template ) ) {
 			return $template;
 		}
@@ -1779,3 +1852,33 @@ function inject_ignored_hooked_blocks_metadata_attributes( $changes, $deprecated
 
 	return $changes;
 }
+
+function wp_assign_new_template_to_theme( $changes, $request ) {
+	// Do not run this for templates created through the old enpoint.
+	$template = $request['id'] ? get_block_template( $request['id'], 'wp_template' ) : null;
+	if ( $template ) {
+		return $changes;
+	}
+	if ( ! isset( $changes->tax_input ) ) {
+		$changes->tax_input = array();
+	}
+	$changes->tax_input['wp_theme'] = isset( $request['theme'] ) ? $request['theme'] : get_stylesheet();
+	// All new templates saved will receive meta so we can distinguish between
+	// templates created the old way as edits and templates created the new way.
+	if ( ! isset( $changes->meta_input ) ) {
+		$changes->meta_input = array();
+	}
+	$changes->meta_input['is_inactive_by_default'] = true;
+	return $changes;
+}
+
+function wp_maybe_activate_template( $post_id ) {
+	$post                   = get_post( $post_id );
+	$is_inactive_by_default = get_post_meta( $post_id, 'is_inactive_by_default', true );
+	if ( $is_inactive_by_default ) {
+		return;
+	}
+	$active_templates                     = get_option( 'active_templates', array() );
+	$active_templates[ $post->post_name ] = $post->ID;
+	update_option( 'active_templates', $active_templates );
+}

src/wp-includes/block-template.php

@@ -164,11 +164,77 @@ function resolve_block_template( $template_type, $template_hierarchy, $fallback_
 		$template_hierarchy
 	);
 
-	// Find all potential templates 'wp_template' post matching the hierarchy.
+	$object            = get_queried_object();
+	$specific_template = $object ? get_page_template_slug( $object ) : null;
+	$active_templates  = (array) get_option( 'active_templates', array() );
+
+	// Remove templates slugs that are deactivated, except if it's the specific
+	// template or index.
+	$slugs = array_filter(
+		$slugs,
+		function ( $slug ) use ( $specific_template, $active_templates ) {
+			$should_ignore = $slug === $specific_template || 'index' === $slug;
+			return $should_ignore || ( ! isset( $active_templates[ $slug ] ) || false !== $active_templates[ $slug ] );
+		}
+	);
+
+	// We expect one template for each slug. Use the active template if it is
+	// set and exists. Otherwise use the static template.
+	$templates       = array();
+	$remaining_slugs = array();
+
+	foreach ( $slugs as $slug ) {
+		if ( $slug === $specific_template || empty( $active_templates[ $slug ] ) ) {
+			$remaining_slugs[] = $slug;
+			continue;
+		}
+
+		// TODO: it need to be possible to set a static template as active.
+		$post = get_post( $active_templates[ $slug ] );
+		if ( ! $post || 'publish' !== $post->post_status ) {
+			$remaining_slugs[] = $slug;
+			continue;
+		}
+
+		$template = _build_block_template_result_from_post( $post );
+
+		// Ensure the active templates are associated with the active theme.
+		// See _build_block_template_object_from_post_object.
+		if ( get_stylesheet() !== $template->theme ) {
+			$remaining_slugs[] = $slug;
+			continue;
+		}
+
+		$templates[] = $template;
+	}
+
+	// Apply the filter to the active templates for backward compatibility.
+	/** This filter is documented in wp-includes/block-template-utils.php */
+	if ( ! empty( $templates ) ) {
+		$templates = apply_filters(
+			'get_block_templates',
+			$templates,
+			array(
+				'slug__in' => array_map(
+					function ( $template ) {
+						return $template->slug;
+					},
+					$templates
+				),
+			),
+			'wp_template'
+		);
+	}
+
+	// For any remaining slugs, use the static template.
 	$query     = array(
-		'slug__in' => $slugs,
+		'slug__in' => $remaining_slugs,
 	);
-	$templates = get_block_templates( $query );
+	$templates = array_merge( $templates, get_registered_block_templates( $query ) );
+
+	if ( $specific_template ) {
+		$templates = array_merge( $templates, get_block_templates( array( 'slug__in' => array( $specific_template ) ) ) );
+	}
 
 	// Order these templates per slug priority.
 	// Build map of template slugs to their priority in the current hierarchy.

src/wp-includes/default-filters.php

@@ -740,6 +740,7 @@
 // Block templates post type 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', 'wp_maybe_activate_template' );
 add_action( 'save_post_wp_template_part', 'wp_set_unique_slug_on_create_template_part' );
 add_action( 'wp_enqueue_scripts', 'wp_enqueue_block_template_skip_link' );
 add_action( 'wp_footer', 'the_block_template_skip_link' ); // Retained for backwards-compatibility. Unhooked by wp_enqueue_block_template_skip_link().
@@ -780,6 +781,10 @@
 add_filter( 'rest_pre_insert_wp_template', 'inject_ignored_hooked_blocks_metadata_attributes' );
 add_filter( 'rest_pre_insert_wp_template_part', 'inject_ignored_hooked_blocks_metadata_attributes' );
 
+// Assign the wp_theme term to any newly created wp_template with the new endpoint.
+// Must run before `inject_ignored_hooked_blocks_metadata_attributes`.
+add_action( 'rest_pre_insert_wp_template', 'wp_assign_new_template_to_theme', 9, 2 );
+
 // Update ignoredHookedBlocks postmeta for some post types.
 add_filter( 'rest_pre_insert_page', 'update_ignored_hooked_blocks_postmeta' );
 add_filter( 'rest_pre_insert_post', 'update_ignored_hooked_blocks_postmeta' );

src/wp-includes/option.php

@@ -2959,6 +2959,25 @@ function register_initial_settings() {
 			'description'  => __( 'Allow people to submit comments on new posts.' ),
 		)
 	);
+
+	register_setting(
+		'reading',
+		'active_templates',
+		array(
+			'type'         => 'object',
+			// Do not set the default value to an empty array! For some reason
+			// that will prevent the option from being set to an empty array.
+			'show_in_rest' => array(
+				'schema' => array(
+					'type'                 => 'object',
+					// Properties can be integers, strings, or false
+					// (deactivated).
+					'additionalProperties' => true,
+				),
+			),
+			'label'        => 'Active Templates',
+		)
+	);
 }
 
 /**

src/wp-includes/post.php

@@ -398,10 +398,8 @@ function create_initial_post_types() {
 			'show_in_menu'                    => false,
 			'show_in_rest'                    => true,
 			'rewrite'                         => false,
-			'rest_base'                       => 'templates',
-			'rest_controller_class'           => 'WP_REST_Templates_Controller',
-			'autosave_rest_controller_class'  => 'WP_REST_Template_Autosaves_Controller',
-			'revisions_rest_controller_class' => 'WP_REST_Template_Revisions_Controller',
+			'rest_base'                       => 'wp_template',
+			'rest_controller_class'           => 'WP_REST_Posts_Controller',
 			'late_route_registration'         => true,
 			'capability_type'                 => array( 'template', 'templates' ),
 			'capabilities'                    => array(
@@ -426,6 +424,7 @@ function create_initial_post_types() {
 				'editor',
 				'revisions',
 				'author',
+				'custom-fields',
 			),
 		)
 	);
@@ -8629,4 +8628,16 @@ function wp_create_initial_post_meta() {
 			),
 		)
 	);
+
+	// Allow setting the is_wp_suggestion meta field, which partly determines if
+	// a template is a custom template.
+	register_post_meta(
+		'wp_template',
+		'is_wp_suggestion',
+		array(
+			'type'         => 'boolean',
+			'show_in_rest' => true,
+			'single'       => true,
+		)
+	);
 }