I18N: Improve _load_textdomain_just_in_time() logic when there are no translation files.

swissspidy · swissspidy · commit bf38bd326c90 · 2023-05-29T08:34:43.000Z
Fixes a performance issue where the JIT logic is invoked for every translation call if the there are no translations in the current locale. With this change, the information is cached by adding `Noop_Translations` instances to the global `$l10n` array. This way, `get_translations_for_domain()` returns earlier, thus avoiding subsequent `_load_textdomain_just_in_time()` calls. Props swissspidy, johnbillion, ocean90. Fixes #58321. git-svn-id: https://develop.svn.wordpress.org/trunk@55865 602fd350-edb4-49c9-b593-d223f7449a82
diff --git a/src/wp-includes/class-wp-textdomain-registry.php b/src/wp-includes/class-wp-textdomain-registry.php
@@ -97,7 +97,7 @@ public function get( $domain, $locale ) {
 	 */
 	public function has( $domain ) {
 		return (
-			! empty( $this->current[ $domain ] ) ||
+			isset( $this->current[ $domain ] ) ||
 			empty( $this->all[ $domain ] ) ||
 			in_array( $domain, $this->domains_with_translations, true )
 		);
diff --git a/src/wp-includes/l10n.php b/src/wp-includes/l10n.php
@@ -834,6 +834,12 @@ function unload_textdomain( $domain, $reloadable = false ) {
 	do_action( 'unload_textdomain', $domain, $reloadable );
 
 	if ( isset( $l10n[ $domain ] ) ) {
+		if ( $l10n[ $domain ] instanceof NOOP_Translations ) {
+			unset( $l10n[ $domain ] );
+
+			return false;
+		}
+
 		unset( $l10n[ $domain ] );
 
 		if ( ! $reloadable ) {
@@ -1307,6 +1313,8 @@ function get_translations_for_domain( $domain ) {
 		$noop_translations = new NOOP_Translations();
 	}
 
+	$l10n[ $domain ] = &$noop_translations;
+
 	return $noop_translations;
 }
 
@@ -1322,7 +1330,7 @@ function get_translations_for_domain( $domain ) {
  */
 function is_textdomain_loaded( $domain ) {
 	global $l10n;
-	return isset( $l10n[ $domain ] );
+	return isset( $l10n[ $domain ] ) && ! $l10n[ $domain ] instanceof NOOP_Translations;
 }
 
 /**
diff --git a/tests/phpunit/tests/l10n/loadTextdomainJustInTime.php b/tests/phpunit/tests/l10n/loadTextdomainJustInTime.php
@@ -121,6 +121,27 @@ public function test_get_translations_for_domain_does_not_return_null_if_overrid
 		$this->assertInstanceOf( 'NOOP_Translations', $translations );
 	}
 
+	/**
+	 * @ticket 58321
+	 *
+	 * @covers ::get_translations_for_domain
+	 */
+	public function test_get_translations_for_domain_get_locale_is_called_only_once() {
+		$filter_locale = new MockAction();
+		add_filter( 'locale', array( $filter_locale, 'filter' ) );
+
+		get_translations_for_domain( 'internationalized-plugin' );
+		get_translations_for_domain( 'internationalized-plugin' );
+		get_translations_for_domain( 'internationalized-plugin' );
+		$translations = get_translations_for_domain( 'internationalized-plugin' );
+
+		remove_filter( 'locale', array( $filter_locale, 'filter' ) );
+
+		$this->assertSame( 1, $filter_locale->get_call_count() );
+		$this->assertInstanceOf( 'NOOP_Translations', $translations );
+		$this->assertFalse( is_textdomain_loaded( 'internationalized-plugin' ) );
+	}
+
 	/**
 	 * @ticket 37113
 	 *
diff --git a/tests/phpunit/tests/l10n/wpLocaleSwitcher.php b/tests/phpunit/tests/l10n/wpLocaleSwitcher.php
@@ -384,7 +384,7 @@ public function test_switch_to_site_locale_if_user_locale_is_set() {
 		$locale_switched_user_locale  = switch_to_locale( $user_locale ); // False.
 		$locale_switched_site_locale  = switch_to_locale( $site_locale ); // True.
 		$site_locale_after_switch     = get_locale();
-		$language_header_after_switch = isset( $l10n['default'] ); // en_US
+		$language_header_after_switch = is_textdomain_loaded( 'default' ); // en_US
 
 		restore_current_locale();
 
