Exclude unminified build artifacts from production distribution

Replace the blanket `build/**` production-include in .gitattributes with
explicit includes for *.php, *.min.js, and loader.js. This excludes
unminified JS (~2.7 MB) and source maps from the production distribution.

Add a SCRIPT_DEBUG fallback file that predefines the wp-build generated
registration functions with file_exists checks, so SCRIPT_DEBUG=true
gracefully falls back to .min.js when unminified files are absent.

Also exclude /routes/** (source TSX/TS/SCSS compiled into build/).

projects/packages/forms/.gitattributes

@@ -9,7 +9,9 @@ package.json      export-ignore
 /src/**/*.min.css production-include
 /src/**/*.rtl.css production-include
 dist/**           production-include
-build/**          production-include
+/build/**/*.php    production-include
+/build/**/*.min.js production-include
+/build/**/loader.js production-include
 
 # Files to exclude from the mirror repo, but included in the monorepo.
 # Remember to end all directories with `/**` to properly tag every file.
@@ -27,3 +29,4 @@ tools/**                 production-exclude
 tsconfig.json            production-exclude
 declarations.d.ts        production-exclude
 global.d.ts              production-exclude
+/routes/**               production-exclude

projects/packages/forms/changelog/update-forms-assets

@@ -0,0 +1,4 @@
+Significance: patch
+Type: changed
+
+Exclude unminified build artifacts from production distribution to reduce plugin size.

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

@@ -30,6 +30,10 @@ public static function load_wp_build() {
 		if ( self::get_admin_query_page() === self::FORMS_WPBUILD_ADMIN_SLUG ) {
 			$wp_build_index = dirname( __DIR__, 2 ) . '/build/build.php';
 			if ( file_exists( $wp_build_index ) ) {
+				// Predefine registration functions with file_exists fallback for
+				// SCRIPT_DEBUG, so production distributions that exclude unminified
+				// JS files don't break when SCRIPT_DEBUG is enabled.
+				require_once __DIR__ . '/wp-build-script-debug-fallback.php';
 				require_once $wp_build_index;
 			}
 		}

projects/packages/forms/src/dashboard/wp-build-script-debug-fallback.php

@@ -0,0 +1,276 @@
+<?php
+/**
+ * SCRIPT_DEBUG fallback for wp-build generated functions.
+ *
+ * Production distributions exclude unminified JS files to reduce plugin size.
+ * The auto-generated code in build/ uses SCRIPT_DEBUG to pick .js vs .min.js
+ * without checking whether the unminified file exists, which would cause 404s
+ * in production when SCRIPT_DEBUG is enabled.
+ *
+ * This file predefines those functions with a file_exists fallback. Because the
+ * generated code wraps each function in function_exists(), our definitions take
+ * precedence when this file is loaded before build.php.
+ *
+ * @package automattic/jetpack-forms
+ */
+
+if ( ! function_exists( 'jetpack_forms_override_script' ) ) {
+	/**
+	 * Registers a script according to `wp_register_script`, honoring any existing
+	 * registration by reassigning its internal properties rather than deregistering.
+	 *
+	 * @param WP_Scripts       $scripts   WP_Scripts instance.
+	 * @param string           $handle    Script handle.
+	 * @param string           $src       Full URL or root-relative path.
+	 * @param array            $deps      Dependencies.
+	 * @param string|bool|null $ver       Version string.
+	 * @param bool             $in_footer Whether to enqueue in footer.
+	 */
+	function jetpack_forms_override_script( $scripts, $handle, $src, $deps = array(), $ver = false, $in_footer = false ) {
+		$script = $scripts->query( $handle, 'registered' );
+		if ( $script ) {
+			$script->src  = $src;
+			$script->deps = $deps;
+			$script->ver  = $ver;
+			$script->args = $in_footer ? 1 : null;
+		} else {
+			$scripts->add( $handle, $src, $deps, $ver, ( $in_footer ? 1 : null ) );
+		}
+
+		if ( in_array( 'wp-i18n', $deps, true ) ) {
+			$scripts->set_translations( $handle );
+		}
+	}
+}
+
+if ( ! function_exists( 'jetpack_forms_register_package_scripts' ) ) {
+	/**
+	 * Register all package scripts with SCRIPT_DEBUG file_exists fallback.
+	 *
+	 * @param WP_Scripts $scripts WP_Scripts instance.
+	 */
+	function jetpack_forms_register_package_scripts( $scripts ) {
+		$build_dir       = dirname( __DIR__, 2 ) . '/build';
+		$build_constants = require $build_dir . '/constants.php';
+		$default_version = ! SCRIPT_DEBUG ? $build_constants['version'] : time();
+
+		$scripts_dir  = $build_dir . '/scripts';
+		$scripts_file = $scripts_dir . '/registry.php';
+
+		if ( ! file_exists( $scripts_file ) ) {
+			return;
+		}
+
+		$scripts_data = require $scripts_file;
+
+		$extension = '.min.js';
+		if ( defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG ) {
+			if ( ! empty( $scripts_data[0]['path'] ) ) {
+				$unminified_path = $scripts_dir . '/' . $scripts_data[0]['path'] . '.js';
+				if ( file_exists( $unminified_path ) ) {
+					$extension = '.js';
+				}
+			}
+		}
+
+		foreach ( $scripts_data as $script_data ) {
+			$asset_file   = $scripts_dir . '/' . $script_data['asset'];
+			$asset        = file_exists( $asset_file ) ? require $asset_file : array();
+			$dependencies = $asset['dependencies'] ?? array();
+			$version      = $asset['version'] ?? $default_version;
+
+			jetpack_forms_override_script(
+				$scripts,
+				$script_data['handle'],
+				$build_constants['build_url'] . 'scripts/' . $script_data['path'] . $extension,
+				$dependencies,
+				$version,
+				true
+			);
+		}
+	}
+
+	add_action( 'wp_default_scripts', 'jetpack_forms_register_package_scripts' );
+}
+
+if ( ! function_exists( 'jetpack_forms_register_script_modules' ) ) {
+	/**
+	 * Register all script modules with SCRIPT_DEBUG file_exists fallback.
+	 */
+	function jetpack_forms_register_script_modules() {
+		$build_dir       = dirname( __DIR__, 2 ) . '/build';
+		$build_constants = require $build_dir . '/constants.php';
+		$modules_dir     = $build_dir . '/modules';
+		$modules_file    = $modules_dir . '/registry.php';
+
+		if ( ! file_exists( $modules_file ) ) {
+			return;
+		}
+
+		$modules   = require $modules_file;
+		$base_url  = $build_constants['build_url'] . 'modules/';
+		$extension = '.min.js';
+		if ( defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG ) {
+			if ( ! empty( $modules[0]['path'] ) ) {
+				$unminified_path = $modules_dir . '/' . $modules[0]['path'] . '.js';
+				if ( file_exists( $unminified_path ) ) {
+					$extension = '.js';
+				}
+			}
+		}
+
+		foreach ( $modules as $module ) {
+			$asset_path = $modules_dir . '/' . $module['asset'];
+			$asset      = file_exists( $asset_path ) ? require $asset_path : array();
+
+			wp_register_script_module(
+				$module['id'],
+				$base_url . $module['path'] . $extension,
+				$asset['module_dependencies'] ?? array(),
+				$asset['version'] ?? false,
+				array(
+					'fetchpriority' => 'low',
+					'in_footer'     => true,
+				)
+			);
+		}
+	}
+
+	add_action( 'wp_default_scripts', 'jetpack_forms_register_script_modules' );
+	remove_action( 'wp_default_scripts', 'wp_default_script_modules' );
+}
+
+if ( ! function_exists( 'jetpack_forms_register_page_routes' ) ) {
+	/**
+	 * Register routes for a page with SCRIPT_DEBUG file_exists fallback.
+	 *
+	 * @param array  $page_routes           Array of route data for the page.
+	 * @param string $register_function_name Name of the function to call for registering each route.
+	 */
+	function jetpack_forms_register_page_routes( $page_routes, $register_function_name ) {
+		$build_dir       = dirname( __DIR__, 2 ) . '/build';
+		$build_constants = require $build_dir . '/constants.php';
+
+		foreach ( $page_routes as $route ) {
+			$content_handle = null;
+			$route_handle   = null;
+
+			// Register content module if exists.
+			if ( $route['has_content'] ) {
+				$content_asset_path = $build_dir . "/routes/{$route['name']}/content.min.asset.php";
+				if ( file_exists( $content_asset_path ) ) {
+					$content_asset  = require $content_asset_path;
+					$content_handle = 'jetpack-forms/routes/' . $route['name'] . '/content';
+					$extension      = '.min.js';
+					if ( defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG ) {
+						$content_unminified = $build_dir . '/routes/' . $route['name'] . '/content.js';
+						if ( file_exists( $content_unminified ) ) {
+							$extension = '.js';
+						}
+					}
+					wp_register_script_module(
+						$content_handle,
+						$build_constants['build_url'] . 'routes/' . $route['name'] . '/content' . $extension,
+						$content_asset['module_dependencies'] ?? array(),
+						$content_asset['version'] ?? false
+					);
+				}
+			}
+
+			// Register route module if exists.
+			if ( $route['has_route'] ) {
+				$route_asset_path = $build_dir . "/routes/{$route['name']}/route.min.asset.php";
+				if ( file_exists( $route_asset_path ) ) {
+					$route_asset  = require $route_asset_path;
+					$route_handle = 'jetpack-forms/routes/' . $route['name'] . '/route';
+					$extension    = '.min.js';
+					if ( defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG ) {
+						$route_unminified = $build_dir . '/routes/' . $route['name'] . '/route.js';
+						if ( file_exists( $route_unminified ) ) {
+							$extension = '.js';
+						}
+					}
+					wp_register_script_module(
+						$route_handle,
+						$build_constants['build_url'] . 'routes/' . $route['name'] . '/route' . $extension,
+						$route_asset['module_dependencies'] ?? array(),
+						$route_asset['version'] ?? false
+					);
+				}
+			}
+
+			// Register route with page.
+			if ( function_exists( $register_function_name ) ) {
+				call_user_func( $register_function_name, $route['path'], $content_handle, $route_handle );
+			}
+		}
+	}
+}
+
+if ( ! function_exists( 'jetpack_forms_override_style' ) ) {
+	/**
+	 * Registers a style, deregistering any existing style by the same handle first.
+	 *
+	 * @param WP_Styles        $styles WP_Styles instance.
+	 * @param string           $handle Stylesheet handle.
+	 * @param string           $src    Full URL or root-relative path.
+	 * @param array            $deps   Dependencies.
+	 * @param string|bool|null $ver    Version string.
+	 * @param string           $media  Media type.
+	 */
+	function jetpack_forms_override_style( $styles, $handle, $src, $deps = array(), $ver = false, $media = 'all' ) {
+		$style = $styles->query( $handle, 'registered' );
+		if ( $style ) {
+			$styles->remove( $handle );
+		}
+		$styles->add( $handle, $src, $deps, $ver, $media );
+	}
+}
+
+if ( ! function_exists( 'jetpack_forms_register_package_styles' ) ) {
+	/**
+	 * Register all package styles with SCRIPT_DEBUG file_exists fallback.
+	 *
+	 * @param WP_Styles $styles WP_Styles instance.
+	 */
+	function jetpack_forms_register_package_styles( $styles ) {
+		$build_dir       = dirname( __DIR__, 2 ) . '/build';
+		$build_constants = require $build_dir . '/constants.php';
+		$default_version = ! SCRIPT_DEBUG ? $build_constants['version'] : time();
+
+		$styles_dir  = $build_dir . '/styles';
+		$styles_file = $styles_dir . '/registry.php';
+
+		if ( ! file_exists( $styles_file ) ) {
+			return;
+		}
+
+		$styles_data = require $styles_file;
+
+		$suffix = '.min';
+		if ( defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG ) {
+			if ( ! empty( $styles_data[0]['path'] ) ) {
+				$unminified_path = $styles_dir . '/' . $styles_data[0]['path'] . '.css';
+				if ( file_exists( $unminified_path ) ) {
+					$suffix = '';
+				}
+			}
+		}
+
+		foreach ( $styles_data as $style_data ) {
+			jetpack_forms_override_style(
+				$styles,
+				$style_data['handle'],
+				$build_constants['build_url'] . 'styles/' . $style_data['path'] . $suffix . '.css',
+				$style_data['dependencies'],
+				$default_version
+			);
+
+			// Enable RTL support.
+			$styles->add_data( $style_data['handle'], 'rtl', 'replace' );
+			$styles->add_data( $style_data['handle'], 'suffix', $suffix );
+		}
+	}
+
+	add_action( 'wp_default_styles', 'jetpack_forms_register_package_styles' );
+}