From 484acd5bb910de93df2e8f3c9e0b60442f33565b Mon Sep 17 00:00:00 2001
From: Khokan Sardar <itzmekhokan@gmail.com>
Date: Tue, 21 Apr 2026 11:37:00 +0530
Subject: [PATCH 1/2] Script Loader: Defer single-page admin init until
 DOMContentLoaded.

The Connectors and Font Library admin screens register a `-prerequisites`
classic-script handle with an empty `src` and attach an inline script that
does `import("@wordpress/boot").then(mod => mod.init(...))`. Because the
handle has no `src`, only the inline is printed, and it runs as a classic
script the moment the parser reaches it.

On fast CDN-fronted hosts (WordPress VIP, CloudFront, etc.) in Chrome,
`@wordpress/boot` is already `<link rel="modulepreload">`-ed, so the
dynamic import resolves and the module evaluates before the parser has
reached the classic deps it relies on (`wp-private-apis`, `wp-components`,
`wp-theme`). At its top-level `@wordpress/boot` reads
`window.wp.theme.privateApis`, which is still undefined at that point,
causing `unlock(undefined)` to throw "Cannot unlock an undefined object".
The mount element stays empty and `initSinglePage` / `init` never runs.

Wrap the dynamic import in `DOMContentLoaded`. The HTML spec guarantees
`DOMContentLoaded` fires only after every parser-blocking classic
`<script>` has executed, so all required globals are populated before
`@wordpress/boot` evaluates. A `document.readyState` guard preserves the
existing behavior when the inline is evaluated after DOM ready (e.g.
injected late).

Applied to all four auto-generated files that share the pattern:
 * src/wp-includes/build/pages/options-connectors/page.php
 * src/wp-includes/build/pages/options-connectors/page-wp-admin.php
 * src/wp-includes/build/pages/font-library/page.php
 * src/wp-includes/build/pages/font-library/page-wp-admin.php

Fixes #65103.

Made-with: Cursor
---
 .../build/pages/font-library/page-wp-admin.php     | 14 ++++++++++++--
 src/wp-includes/build/pages/font-library/page.php  | 14 ++++++++++++--
 .../pages/options-connectors/page-wp-admin.php     | 14 ++++++++++++--
 .../build/pages/options-connectors/page.php        | 14 ++++++++++++--
 4 files changed, 48 insertions(+), 8 deletions(-)

diff --git a/src/wp-includes/build/pages/font-library/page-wp-admin.php b/src/wp-includes/build/pages/font-library/page-wp-admin.php
index 4d41be02ae892..37d4e5b72e73c 100644
--- a/src/wp-includes/build/pages/font-library/page-wp-admin.php
+++ b/src/wp-includes/build/pages/font-library/page-wp-admin.php
@@ -153,11 +153,21 @@ function wp_font_library_wp_admin_enqueue_scripts( $hook_suffix ) {
 		// 2. It initializes the boot module as an inline script.
 		wp_register_script( 'font-library-wp-admin-prerequisites', '', $asset['dependencies'], $asset['version'], true );
 
-		// Add inline script to initialize the app using initSinglePage (no menuItems)
+		/*
+		 * Add inline script to initialize the app using initSinglePage (no menuItems).
+		 *
+		 * The call is deferred until DOMContentLoaded so that all classic script
+		 * dependencies of @wordpress/boot (wp-private-apis, wp-components, wp-theme,
+		 * etc.) have finished parsing and executing before the dynamic module import
+		 * resolves. Without this, a modulepreloaded @wordpress/boot can win the race
+		 * against the classic-script-printing pass on fast CDN-fronted hosts in
+		 * Chrome, evaluating before wp.theme.privateApis is defined and throwing
+		 * "Cannot unlock an undefined object". See Trac #65103.
+		 */
 		wp_add_inline_script(
 			'font-library-wp-admin-prerequisites',
 			sprintf(
-				'import("@wordpress/boot").then(mod => mod.initSinglePage({mountId: "%s", routes: %s}));',
+				'(function(){var run=function(){import("@wordpress/boot").then(function(mod){mod.initSinglePage({mountId: "%s", routes: %s});});};if(document.readyState==="loading"){document.addEventListener("DOMContentLoaded",run);}else{run();}})();',
 				'font-library-wp-admin-app',
 				wp_json_encode( $routes, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES )
 			)
diff --git a/src/wp-includes/build/pages/font-library/page.php b/src/wp-includes/build/pages/font-library/page.php
index e2849c954ba37..8431004991d8a 100644
--- a/src/wp-includes/build/pages/font-library/page.php
+++ b/src/wp-includes/build/pages/font-library/page.php
@@ -159,12 +159,22 @@ function wp_font_library_render_page() {
 		// 2. It initializes the boot module as an inline script.
 		wp_register_script( 'font-library-prerequisites', '', $asset['dependencies'], $asset['version'], true );
 
-		// Add inline script to initialize the app
+		/*
+		 * Add inline script to initialize the app.
+		 *
+		 * The call is deferred until DOMContentLoaded so that all classic script
+		 * dependencies of @wordpress/boot (wp-private-apis, wp-components, wp-theme,
+		 * etc.) have finished parsing and executing before the dynamic module import
+		 * resolves. Without this, a modulepreloaded @wordpress/boot can win the race
+		 * against the classic-script-printing pass on fast CDN-fronted hosts in
+		 * Chrome, evaluating before wp.theme.privateApis is defined and throwing
+		 * "Cannot unlock an undefined object". See Trac #65103.
+		 */
 		$init_modules = [];
 		wp_add_inline_script(
 			'font-library-prerequisites',
 			sprintf(
-				'import("@wordpress/boot").then(mod => mod.init({mountId: "%s", menuItems: %s, routes: %s, initModules: %s, dashboardLink: "%s"}));',
+				'(function(){var run=function(){import("@wordpress/boot").then(function(mod){mod.init({mountId: "%s", menuItems: %s, routes: %s, initModules: %s, dashboardLink: "%s"});});};if(document.readyState==="loading"){document.addEventListener("DOMContentLoaded",run);}else{run();}})();',
 				'font-library-app',
 				wp_json_encode( $menu_items, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES ),
 				wp_json_encode( $routes, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES ),
diff --git a/src/wp-includes/build/pages/options-connectors/page-wp-admin.php b/src/wp-includes/build/pages/options-connectors/page-wp-admin.php
index 3f3048b8fb98b..0e3a782eba34d 100644
--- a/src/wp-includes/build/pages/options-connectors/page-wp-admin.php
+++ b/src/wp-includes/build/pages/options-connectors/page-wp-admin.php
@@ -153,11 +153,21 @@ function wp_options_connectors_wp_admin_enqueue_scripts( $hook_suffix ) {
 		// 2. It initializes the boot module as an inline script.
 		wp_register_script( 'options-connectors-wp-admin-prerequisites', '', $asset['dependencies'], $asset['version'], true );
 
-		// Add inline script to initialize the app using initSinglePage (no menuItems)
+		/*
+		 * Add inline script to initialize the app using initSinglePage (no menuItems).
+		 *
+		 * The call is deferred until DOMContentLoaded so that all classic script
+		 * dependencies of @wordpress/boot (wp-private-apis, wp-components, wp-theme,
+		 * etc.) have finished parsing and executing before the dynamic module import
+		 * resolves. Without this, a modulepreloaded @wordpress/boot can win the race
+		 * against the classic-script-printing pass on fast CDN-fronted hosts in
+		 * Chrome, evaluating before wp.theme.privateApis is defined and throwing
+		 * "Cannot unlock an undefined object". See Trac #65103.
+		 */
 		wp_add_inline_script(
 			'options-connectors-wp-admin-prerequisites',
 			sprintf(
-				'import("@wordpress/boot").then(mod => mod.initSinglePage({mountId: "%s", routes: %s}));',
+				'(function(){var run=function(){import("@wordpress/boot").then(function(mod){mod.initSinglePage({mountId: "%s", routes: %s});});};if(document.readyState==="loading"){document.addEventListener("DOMContentLoaded",run);}else{run();}})();',
 				'options-connectors-wp-admin-app',
 				wp_json_encode( $routes, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES )
 			)
diff --git a/src/wp-includes/build/pages/options-connectors/page.php b/src/wp-includes/build/pages/options-connectors/page.php
index 6009dbb2570a9..a7755512b3d71 100644
--- a/src/wp-includes/build/pages/options-connectors/page.php
+++ b/src/wp-includes/build/pages/options-connectors/page.php
@@ -159,12 +159,22 @@ function wp_options_connectors_render_page() {
 		// 2. It initializes the boot module as an inline script.
 		wp_register_script( 'options-connectors-prerequisites', '', $asset['dependencies'], $asset['version'], true );
 
-		// Add inline script to initialize the app
+		/*
+		 * Add inline script to initialize the app.
+		 *
+		 * The call is deferred until DOMContentLoaded so that all classic script
+		 * dependencies of @wordpress/boot (wp-private-apis, wp-components, wp-theme,
+		 * etc.) have finished parsing and executing before the dynamic module import
+		 * resolves. Without this, a modulepreloaded @wordpress/boot can win the race
+		 * against the classic-script-printing pass on fast CDN-fronted hosts in
+		 * Chrome, evaluating before wp.theme.privateApis is defined and throwing
+		 * "Cannot unlock an undefined object". See Trac #65103.
+		 */
 		$init_modules = [];
 		wp_add_inline_script(
 			'options-connectors-prerequisites',
 			sprintf(
-				'import("@wordpress/boot").then(mod => mod.init({mountId: "%s", menuItems: %s, routes: %s, initModules: %s, dashboardLink: "%s"}));',
+				'(function(){var run=function(){import("@wordpress/boot").then(function(mod){mod.init({mountId: "%s", menuItems: %s, routes: %s, initModules: %s, dashboardLink: "%s"});});};if(document.readyState==="loading"){document.addEventListener("DOMContentLoaded",run);}else{run();}})();',
 				'options-connectors-app',
 				wp_json_encode( $menu_items, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES ),
 				wp_json_encode( $routes, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES ),

From c4f1de3f995cad3cf66fb8f7bfaee70e28ed5cad Mon Sep 17 00:00:00 2001
From: Khokan Sardar <itzmekhokan@gmail.com>
Date: Tue, 21 Apr 2026 11:53:32 +0530
Subject: [PATCH 2/2] Coding Standards: Align inline comments with WP
 documentation style.

Follow-up to [65103] feedback. Adjust the multi-line `/* */` comments
added for the DOMContentLoaded deferral so they match the WordPress PHP
inline-documentation conventions: no DocBlock-style summary-then-blank
separator (that structure is reserved for `/** */`), and use the short
`See #65103.` form for Trac references instead of `See Trac #65103.` to
match usages throughout core (`See #38883`, `See #40146`, etc.).

See #65103.

Made-with: Cursor
---
 .../build/pages/font-library/page-wp-admin.php        | 11 +++++------
 src/wp-includes/build/pages/font-library/page.php     | 11 +++++------
 .../build/pages/options-connectors/page-wp-admin.php  | 11 +++++------
 .../build/pages/options-connectors/page.php           | 11 +++++------
 4 files changed, 20 insertions(+), 24 deletions(-)

diff --git a/src/wp-includes/build/pages/font-library/page-wp-admin.php b/src/wp-includes/build/pages/font-library/page-wp-admin.php
index 37d4e5b72e73c..440b07f6fdaaa 100644
--- a/src/wp-includes/build/pages/font-library/page-wp-admin.php
+++ b/src/wp-includes/build/pages/font-library/page-wp-admin.php
@@ -155,14 +155,13 @@ function wp_font_library_wp_admin_enqueue_scripts( $hook_suffix ) {
 
 		/*
 		 * Add inline script to initialize the app using initSinglePage (no menuItems).
-		 *
-		 * The call is deferred until DOMContentLoaded so that all classic script
-		 * dependencies of @wordpress/boot (wp-private-apis, wp-components, wp-theme,
-		 * etc.) have finished parsing and executing before the dynamic module import
-		 * resolves. Without this, a modulepreloaded @wordpress/boot can win the race
+		 * The dynamic import is deferred until DOMContentLoaded so that all classic
+		 * script dependencies of @wordpress/boot (wp-private-apis, wp-components,
+		 * wp-theme, etc.) have finished parsing and executing before the boot module
+		 * evaluates. Otherwise, a modulepreloaded @wordpress/boot can win the race
 		 * against the classic-script-printing pass on fast CDN-fronted hosts in
 		 * Chrome, evaluating before wp.theme.privateApis is defined and throwing
-		 * "Cannot unlock an undefined object". See Trac #65103.
+		 * "Cannot unlock an undefined object". See #65103.
 		 */
 		wp_add_inline_script(
 			'font-library-wp-admin-prerequisites',
diff --git a/src/wp-includes/build/pages/font-library/page.php b/src/wp-includes/build/pages/font-library/page.php
index 8431004991d8a..d1cc449155ebd 100644
--- a/src/wp-includes/build/pages/font-library/page.php
+++ b/src/wp-includes/build/pages/font-library/page.php
@@ -161,14 +161,13 @@ function wp_font_library_render_page() {
 
 		/*
 		 * Add inline script to initialize the app.
-		 *
-		 * The call is deferred until DOMContentLoaded so that all classic script
-		 * dependencies of @wordpress/boot (wp-private-apis, wp-components, wp-theme,
-		 * etc.) have finished parsing and executing before the dynamic module import
-		 * resolves. Without this, a modulepreloaded @wordpress/boot can win the race
+		 * The dynamic import is deferred until DOMContentLoaded so that all classic
+		 * script dependencies of @wordpress/boot (wp-private-apis, wp-components,
+		 * wp-theme, etc.) have finished parsing and executing before the boot module
+		 * evaluates. Otherwise, a modulepreloaded @wordpress/boot can win the race
 		 * against the classic-script-printing pass on fast CDN-fronted hosts in
 		 * Chrome, evaluating before wp.theme.privateApis is defined and throwing
-		 * "Cannot unlock an undefined object". See Trac #65103.
+		 * "Cannot unlock an undefined object". See #65103.
 		 */
 		$init_modules = [];
 		wp_add_inline_script(
diff --git a/src/wp-includes/build/pages/options-connectors/page-wp-admin.php b/src/wp-includes/build/pages/options-connectors/page-wp-admin.php
index 0e3a782eba34d..3f31e5557d3fb 100644
--- a/src/wp-includes/build/pages/options-connectors/page-wp-admin.php
+++ b/src/wp-includes/build/pages/options-connectors/page-wp-admin.php
@@ -155,14 +155,13 @@ function wp_options_connectors_wp_admin_enqueue_scripts( $hook_suffix ) {
 
 		/*
 		 * Add inline script to initialize the app using initSinglePage (no menuItems).
-		 *
-		 * The call is deferred until DOMContentLoaded so that all classic script
-		 * dependencies of @wordpress/boot (wp-private-apis, wp-components, wp-theme,
-		 * etc.) have finished parsing and executing before the dynamic module import
-		 * resolves. Without this, a modulepreloaded @wordpress/boot can win the race
+		 * The dynamic import is deferred until DOMContentLoaded so that all classic
+		 * script dependencies of @wordpress/boot (wp-private-apis, wp-components,
+		 * wp-theme, etc.) have finished parsing and executing before the boot module
+		 * evaluates. Otherwise, a modulepreloaded @wordpress/boot can win the race
 		 * against the classic-script-printing pass on fast CDN-fronted hosts in
 		 * Chrome, evaluating before wp.theme.privateApis is defined and throwing
-		 * "Cannot unlock an undefined object". See Trac #65103.
+		 * "Cannot unlock an undefined object". See #65103.
 		 */
 		wp_add_inline_script(
 			'options-connectors-wp-admin-prerequisites',
diff --git a/src/wp-includes/build/pages/options-connectors/page.php b/src/wp-includes/build/pages/options-connectors/page.php
index a7755512b3d71..b0e49b11e2834 100644
--- a/src/wp-includes/build/pages/options-connectors/page.php
+++ b/src/wp-includes/build/pages/options-connectors/page.php
@@ -161,14 +161,13 @@ function wp_options_connectors_render_page() {
 
 		/*
 		 * Add inline script to initialize the app.
-		 *
-		 * The call is deferred until DOMContentLoaded so that all classic script
-		 * dependencies of @wordpress/boot (wp-private-apis, wp-components, wp-theme,
-		 * etc.) have finished parsing and executing before the dynamic module import
-		 * resolves. Without this, a modulepreloaded @wordpress/boot can win the race
+		 * The dynamic import is deferred until DOMContentLoaded so that all classic
+		 * script dependencies of @wordpress/boot (wp-private-apis, wp-components,
+		 * wp-theme, etc.) have finished parsing and executing before the boot module
+		 * evaluates. Otherwise, a modulepreloaded @wordpress/boot can win the race
 		 * against the classic-script-printing pass on fast CDN-fronted hosts in
 		 * Chrome, evaluating before wp.theme.privateApis is defined and throwing
-		 * "Cannot unlock an undefined object". See Trac #65103.
+		 * "Cannot unlock an undefined object". See #65103.
 		 */
 		$init_modules = [];
 		wp_add_inline_script(