From afd5c26bfa648c6a3632cb32bbee08a98ee325a1 Mon Sep 17 00:00:00 2001
From: Daniel Richards <daniel.richards@automattic.com>
Date: Fri, 26 Nov 2021 15:15:05 +0800
Subject: [PATCH 1/2] Extract to separate function

---
 lib/full-site-editing/edit-site-page.php | 35 ++++++++++++++----------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/lib/full-site-editing/edit-site-page.php b/lib/full-site-editing/edit-site-page.php
index 8a02d2755c1e2a..7878642abb8fb4 100644
--- a/lib/full-site-editing/edit-site-page.php
+++ b/lib/full-site-editing/edit-site-page.php
@@ -76,21 +76,7 @@ function gutenberg_get_editor_styles() {
 	return $styles;
 }
 
-/**
- * Initialize the Gutenberg Templates List Page.
- *
- * @param array $settings The editor settings.
- */
-function gutenberg_edit_site_list_init( $settings ) {
-	wp_enqueue_script( 'wp-edit-site' );
-	wp_enqueue_style( 'wp-edit-site' );
-	wp_enqueue_media();
-
-	$post_type = get_post_type_object( $_GET['postType'] );
-
-	if ( ! $post_type ) {
-		wp_die( __( 'Invalid post type.', 'gutenberg' ) );
-	}
+function gutenberg_edit_site_list_preload_data( $post_type ) {
 
 	$preload_data = array_reduce(
 		array(
@@ -111,6 +97,25 @@ function gutenberg_edit_site_list_init( $settings ) {
 		),
 		'after'
 	);
+}
+
+/**
+ * Initialize the Gutenberg Templates List Page.
+ *
+ * @param array $settings The editor settings.
+ */
+function gutenberg_edit_site_list_init( $settings ) {
+	wp_enqueue_script( 'wp-edit-site' );
+	wp_enqueue_style( 'wp-edit-site' );
+	wp_enqueue_media();
+
+	$post_type = get_post_type_object( $_GET['postType'] );
+
+	if ( ! $post_type ) {
+		wp_die( __( 'Invalid post type.', 'gutenberg' ) );
+	}
+
+	gutenberg_edit_site_list_preload_data( $post_type );
 
 	wp_add_inline_script(
 		'wp-edit-site',

From c42fa60fbaab329ada544c8b0c7ba088c661b392 Mon Sep 17 00:00:00 2001
From: Daniel Richards <daniel.richards@automattic.com>
Date: Fri, 26 Nov 2021 16:16:45 +0800
Subject: [PATCH 2/2] Add preloading for template list associated data

---
 lib/full-site-editing/edit-site-page.php | 62 ++++++++++++++++++++++--
 1 file changed, 57 insertions(+), 5 deletions(-)

diff --git a/lib/full-site-editing/edit-site-page.php b/lib/full-site-editing/edit-site-page.php
index 7878642abb8fb4..2d8ea2e6995082 100644
--- a/lib/full-site-editing/edit-site-page.php
+++ b/lib/full-site-editing/edit-site-page.php
@@ -76,14 +76,66 @@ function gutenberg_get_editor_styles() {
 	return $styles;
 }
 
+/**
+ * Preloads data for the templates list page.
+ *
+ * @param WP_Post_Type $post_type The post type that the list page will show.
+ */
 function gutenberg_edit_site_list_preload_data( $post_type ) {
+	$posts_path = "/wp/v2/$post_type->rest_base?context=edit&per_page=-1";
+	$path       = untrailingslashit( $posts_path );
+	$path_parts = parse_url( $path );
+	$request    = new WP_REST_Request( 'GET', $path_parts['path'] );
+
+	if ( ! empty( $path_parts['query'] ) ) {
+		parse_str( $path_parts['query'], $query_params );
+		$request->set_query_params( $query_params );
+	}
+
+	$dynamic_preload_requests = array();
+	$response                 = rest_do_request( $request );
+
+	if ( 200 === $response->status ) {
+		$server = rest_get_server();
+		$posts  = (array) $server->response_to_data( $response, false );
+
+		foreach ( $posts as $post_data ) {
+			if ( ! empty( $post_data['author'] ) ) {
+				$author_id                  = $post_data['author'];
+				$dynamic_preload_requests[] = "/wp/v2/users/$author_id?context=edit";
+			}
+
+			if ( 'wp_template' === $post_data['type'] || 'wp_template_part' === $post_data['type'] ) {
+				$has_theme_origin_or_source =
+					( ! empty( $post_data['source'] ) && 'theme' === $post_data['source'] ) ||
+					( ! empty( $post_data['origin'] ) && 'theme' === $post_data['origin'] );
+
+				if ( $has_theme_origin_or_source ) {
+					$theme_id                   = $post_data['theme'];
+					$dynamic_preload_requests[] = "/wp/v2/themes/$theme_id?context=edit";
+				}
+
+				$has_plugin_origin_or_source =
+					( ! empty( $post_data['source'] ) && 'plugin' === $post_data['source'] ) ||
+					( ! empty( $post_data['origin'] ) && 'plugin' === $post_data['origin'] );
+
+				if ( $has_plugin_origin_or_source ) {
+					$plugin_id                  = $post_data['theme'];
+					$dynamic_preload_requests[] = "/wp/v2/plugins/$plugin_id?context=edit";
+				}
+			}
+		}
+	}
 
 	$preload_data = array_reduce(
-		array(
-			'/',
-			"/wp/v2/types/$post_type->name?context=edit",
-			'/wp/v2/types?context=edit',
-			"/wp/v2/$post_type->rest_base?context=edit&per_page=-1",
+		array_merge(
+			array(
+				'/',
+				"/wp/v2/types/$post_type->name?context=edit",
+				'/wp/v2/types?context=edit',
+				$posts_path,
+			),
+			array_unique( $dynamic_preload_requests )
 		),
 		'rest_preload_api_request',
 		array()