I18N: Auto-detect script module translations.

Stop requiring explicit wp_set_script_module_translations() calls to
enable translation loading. Instead, print_script_module_translations()
now iterates every enqueued script module (and its dependencies) and
calls load_script_module_textdomain() with the 'default' text domain
by default.

This removes the need to maintain a hardcoded list of modules that
use wp-i18n in wp_default_script_modules(), and lets translations
flow through automatically as long as the JSON chunk for a module
exists on disk. Modules that use a non-default text domain or a
custom translation path can still opt in via set_translations().

Author: manzoorwanijk

src/wp-includes/class-wp-script-modules.php

@@ -349,11 +349,13 @@ public function deregister( string $id ) {
 	}
 
 	/**
-	 * Sets translated strings for a script module.
+	 * Overrides the text domain and path used to load translations for a script module.
 	 *
-	 * Works similar to {@see WP_Scripts::set_translations()} but for script modules.
-	 * The translations will be loaded and output as inline scripts before
-	 * the script modules are printed, calling `wp.i18n.setLocaleData()`.
+	 * This is only needed for modules whose text domain differs from 'default'
+	 * or whose translation files live outside the standard locations, for
+	 * example plugin modules that register their own text domain. Translations
+	 * for modules that use the default domain are loaded automatically by
+	 * {@see WP_Script_Modules::print_script_module_translations()}.
 	 *
 	 * @since 7.0.0
 	 *
@@ -376,26 +378,32 @@ public function set_translations( string $id, string $domain = 'default', string
 	}
 
 	/**
-	 * Prints translations for all enqueued script modules that have translations set.
+	 * Prints translations for all enqueued script modules.
 	 *
 	 * Outputs inline `<script>` tags that call `wp.i18n.setLocaleData()` with
 	 * the translated strings for each script module. This must run before
 	 * the script modules execute.
 	 *
+	 * Auto-detects the text domain and translation path for each module from
+	 * its source URL. Modules whose text domain or path differs from the
+	 * defaults can opt into a specific domain/path via
+	 * {@see WP_Script_Modules::set_translations()}.
+	 *
 	 * @since 7.0.0
 	 */
 	public function print_script_module_translations(): void {
 		// Collect all module IDs that will be on the page (enqueued + their dependencies).
 		$module_ids = $this->get_sorted_dependencies( $this->queue );
 
 		foreach ( $module_ids as $id ) {
-			if ( ! isset( $this->translations[ $id ] ) ) {
-				continue;
+			if ( isset( $this->translations[ $id ] ) ) {
+				$domain = $this->translations[ $id ]['domain'];
+				$path   = $this->translations[ $id ]['path'];
+			} else {
+				$domain = 'default';
+				$path   = '';
 			}
 
-			$domain = $this->translations[ $id ]['domain'];
-			$path   = $this->translations[ $id ]['path'];
-
 			$json_translations = load_script_module_textdomain( $id, $domain, $path );
 
 			if ( ! $json_translations ) {

src/wp-includes/script-modules.php

@@ -139,10 +139,12 @@ function wp_deregister_script_module( string $id ) {
 }
 
 /**
- * Sets translated strings for a script module.
+ * Overrides the text domain and path used to load translations for a script module.
  *
- * Works similar to {@see wp_set_script_translations()} but for script modules
- * registered via {@see wp_register_script_module()}.
+ * Translations for script modules are loaded automatically from the default
+ * text domain and language directory. Use this function only when a module's
+ * text domain differs from `'default'` or when translation files live outside
+ * the standard location, for example plugin modules using their own text domain.
  *
  * @since 7.0.0
  *
@@ -151,7 +153,7 @@ function wp_deregister_script_module( string $id ) {
  * @param string $id     The identifier of the script module.
  * @param string $domain Optional. Text domain. Default 'default'.
  * @param string $path   Optional. The full file path to the directory containing translation files.
- * @return bool True if the text domain was successfully localized, false otherwise.
+ * @return bool True if the text domain was registered, false if the module is not registered.
  */
 function wp_set_script_module_translations( string $id, string $domain = 'default', string $path = '' ): bool {
 	return wp_script_modules()->set_translations( $id, $domain, $path );
@@ -216,11 +218,6 @@ function wp_default_script_modules() {
 		$path        = includes_url( "js/dist/script-modules/{$file_name}" );
 		$module_deps = $script_module_data['module_dependencies'] ?? array();
 		wp_register_script_module( $script_module_id, $path, $module_deps, $script_module_data['version'], $args );
-
-		// Set up translations for script modules that use wp-i18n.
-		if ( isset( $script_module_data['dependencies'] ) && in_array( 'wp-i18n', $script_module_data['dependencies'], true ) ) {
-			wp_set_script_module_translations( $script_module_id, 'default' );
-		}
 	}
 
 	wp_register_script_module(

tests/phpunit/tests/script-modules/wpScriptModules.php

@@ -2682,8 +2682,8 @@ public function test_print_script_module_translations_outputs_nothing_for_non_en
 	}
 
 	/**
-	 * Tests that print_script_module_translations() outputs an inline script
-	 * calling wp.i18n.setLocaleData() when translations are available.
+	 * Tests that print_script_module_translations() auto-detects translations
+	 * for enqueued modules without requiring an explicit set_translations() call.
 	 *
 	 * @ticket 65015
 	 *
@@ -2693,7 +2693,6 @@ public function test_print_script_module_translations_outputs_nothing_for_non_en
 	public function test_print_script_module_translations_outputs_set_locale_data() {
 		$this->script_modules->register( 'test-module', '/wp-includes/js/test-module.js' );
 		$this->script_modules->enqueue( 'test-module' );
-		$this->script_modules->set_translations( 'test-module', 'default' );
 
 		// Provide test translations via the pre_load_script_translations filter
 		// so no fixture files are needed.
@@ -2763,7 +2762,6 @@ public function test_print_script_module_translations_includes_dependencies() {
 		$this->script_modules->register( 'dep-module', '/wp-includes/js/dep-module.js' );
 		$this->script_modules->register( 'main-module', '/wp-includes/js/main-module.js', array( 'dep-module' ) );
 		$this->script_modules->enqueue( 'main-module' );
-		$this->script_modules->set_translations( 'dep-module', 'default' );
 
 		add_filter(
 			'pre_load_script_translations',
@@ -2815,4 +2813,49 @@ static function ( $relative, $src, $is_module ) use ( &$filtered ) {
 		$this->assertStringContainsString( 'dep-module-js-module-translations', $script_text, 'Dependency module translations should be printed.' );
 		$this->assertStringContainsString( 'Mundo', $script_text, 'Output should contain the dependency translation.' );
 	}
+
+	/**
+	 * Tests that set_translations() can override the auto-detected text domain.
+	 *
+	 * @ticket 65015
+	 *
+	 * @covers WP_Script_Modules::print_script_module_translations
+	 * @covers WP_Script_Modules::set_translations
+	 */
+	public function test_print_script_module_translations_respects_set_translations_override() {
+		$this->script_modules->register( 'test-module', '/wp-includes/js/test-module.js' );
+		$this->script_modules->enqueue( 'test-module' );
+		$this->script_modules->set_translations( 'test-module', 'my-plugin' );
+
+		$seen_domain = null;
+		add_filter(
+			'pre_load_script_translations',
+			static function ( $translations, $file, $handle, $domain ) use ( &$seen_domain ) {
+				if ( 'test-module' !== $handle ) {
+					return $translations;
+				}
+				$seen_domain = $domain;
+				return wp_json_encode(
+					array(
+						'locale_data' => array(
+							'messages' => array(
+								''      => array(
+									'domain' => 'my-plugin',
+									'lang'   => 'es',
+								),
+								'Hello' => array( 'Hola' ),
+							),
+						),
+					)
+				);
+			},
+			10,
+			4
+		);
+
+		$output = get_echo( array( $this->script_modules, 'print_script_module_translations' ) );
+
+		$this->assertSame( 'my-plugin', $seen_domain, 'load_script_module_textdomain() should be called with the overridden domain.' );
+		$this->assertStringContainsString( 'Hola', $output );
+	}
 }