Add wp-build-polyfills package for WP < 7.0 compatibility

projects/packages/forms/changelog/fix-polyfill-wp-build-dependencies

@@ -0,0 +1,4 @@
+Significance: minor
+Type: fixed
+
+Add polyfills for wp-build unbundled dependencies

projects/packages/forms/composer.json

@@ -7,6 +7,7 @@
 		"php": ">=7.2",
 		"automattic/jetpack-blocks": "@dev",
 		"automattic/jetpack-assets": "@dev",
+		"automattic/jetpack-wp-build-polyfills": "@dev",
 		"automattic/jetpack-connection": "@dev",
 		"automattic/jetpack-device-detection": "@dev",
 		"automattic/jetpack-external-connections": "@dev",

projects/packages/forms/package.json

@@ -16,8 +16,9 @@
 	"author": "Automattic",
 	"type": "module",
 	"scripts": {
-		"build": "pnpm run clean && pnpm run build:blocks && pnpm run build:contact-form && pnpm run build:dashboard && pnpm run build:wp-build && pnpm run build:form-editor && pnpm run module:build",
+		"build": "pnpm run clean && pnpm run build:blocks && pnpm run build:contact-form && pnpm run build:dashboard && pnpm run build:wp-build && pnpm run build:boot-asset && pnpm run build:form-editor && pnpm run module:build",
 		"build:blocks": "webpack --config ./tools/webpack.config.blocks.js",
+		"build:boot-asset": "provide-boot-asset-file",
 		"build:contact-form": "webpack --config ./tools/webpack.config.contact-form.js",
 		"build:dashboard": "webpack --config ./tools/webpack.config.dashboard.js",
 		"build:form-editor": "webpack --config ./tools/webpack.config.form-editor.js",
@@ -99,6 +100,7 @@
 		"@automattic/color-studio": "4.1.0",
 		"@automattic/jetpack-base-styles": "workspace:*",
 		"@automattic/jetpack-webpack-config": "workspace:*",
+		"@automattic/jetpack-wp-build-polyfills": "workspace:*",
 		"@automattic/remove-asset-webpack-plugin": "workspace:*",
 		"@babel/core": "7.29.0",
 		"@babel/runtime": "7.28.6",
@@ -112,7 +114,7 @@
 		"@typescript/native-preview": "7.0.0-dev.20260225.1",
 		"@wordpress/api-fetch": "7.41.0",
 		"@wordpress/browserslist-config": "6.41.0",
-		"@wordpress/build": "0.8.0",
+		"@wordpress/build": "0.10.1-next.v.202603102151.0",
 		"@wordpress/date": "5.41.0",
 		"autoprefixer": "10.4.20",
 		"browserslist": "^4.24.0",

projects/packages/forms/src/dashboard/class-dashboard.php

@@ -12,6 +12,7 @@
 use Automattic\Jetpack\Connection\Initial_State as Connection_Initial_State;
 use Automattic\Jetpack\Forms\ContactForm\Contact_Form_Plugin;
 use Automattic\Jetpack\Tracking;
+use Automattic\Jetpack\WP_Build_Polyfills\WP_Build_Polyfills;
 
 if ( ! defined( 'ABSPATH' ) ) {
 	exit( 0 );
@@ -36,9 +37,19 @@ public static function load_wp_build() {
 					: 'inbox';
 
 				wp_safe_redirect( self::get_forms_admin_url( $default_tab ) );
+
 				exit;
 			}
 
+			// Register polyfills for WP < 7.0 (must run before build.php).
+			WP_Build_Polyfills::register(
+				'jetpack-forms',
+				array_merge(
+					WP_Build_Polyfills::SCRIPT_HANDLES,
+					WP_Build_Polyfills::MODULE_IDS
+				)
+			);
+
 			$wp_build_index = dirname( __DIR__, 2 ) . '/build/build.php';
 
 			if ( file_exists( $wp_build_index ) ) {