I18N: Do not load translations directly in `load_*_textdomain`.

In [59127], `_doing_it_wrong` warnings were added if plugins or themes load translations too early, either through a manual function call or just-in-time loading.

Because many plugins and themes still manually call `load_plugin_textdomain()`, `load_theme_textdomain()` or `load_muplugin_textdomain()`, even though they don't have to anymore, that caused a lot of warnings.

With this new approach, these functions merely register the translations path in the existing `WP_Textdomain_Registry` and do not immediately try to load the translations anymore. The loading is all handled by the just-in-time functionality.

This way, warnings will only be emitted if triggering the just-in-time loading too early, greatly improving the developer experience and to a degree also performance.

Props swissspidy, sergeybiryukov, mukesh27.
See #44937.


Built from https://develop.svn.wordpress.org/trunk@59157


git-svn-id: http://core.svn.wordpress.org/trunk@58552 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/l10n.php

@@ -983,6 +983,7 @@ function load_default_textdomain( $locale = null ) {
  *
  * @since 1.5.0
  * @since 4.6.0 The function now tries to load the .mo file from the languages directory first.
+ * @since 6.7.0 Translations are no longer immediately loaded, but handed off to the just-in-time loading mechanism.
  *
  * @param string       $domain          Unique identifier for retrieving translated strings
  * @param string|false $deprecated      Optional. Deprecated. Use the $plugin_rel_path parameter instead.
@@ -999,36 +1000,6 @@ function load_plugin_textdomain( $domain, $deprecated = false, $plugin_rel_path
 		return false;
 	}
 
-	if ( ! doing_action( 'after_setup_theme' ) && ! did_action( 'after_setup_theme' ) ) {
-		_doing_it_wrong(
-			__FUNCTION__,
-			sprintf(
-				/* translators: 1: The text domain. 2: 'after_setup_theme'. */
-				__( 'Attempted to load translations for the %1$s domain too early. Translations should be loaded after the %2$s action has fired, to ensure that the current user is already set up.' ),
-				'<code>' . $domain . '</code>',
-				'<code>after_setup_theme</code>'
-			),
-			'6.7.0'
-		);
-	}
-
-	/**
-	 * Filters a plugin's locale.
-	 *
-	 * @since 3.0.0
-	 *
-	 * @param string $locale The plugin's current locale.
-	 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
-	 */
-	$locale = apply_filters( 'plugin_locale', determine_locale(), $domain );
-
-	$mofile = $domain . '-' . $locale . '.mo';
-
-	// Try to load from the languages directory first.
-	if ( load_textdomain( $domain, WP_LANG_DIR . '/plugins/' . $mofile, $locale ) ) {
-		return true;
-	}
-
 	if ( false !== $plugin_rel_path ) {
 		$path = WP_PLUGIN_DIR . '/' . trim( $plugin_rel_path, '/' );
 	} elseif ( false !== $deprecated ) {
@@ -1040,7 +1011,7 @@ function load_plugin_textdomain( $domain, $deprecated = false, $plugin_rel_path
 
 	$wp_textdomain_registry->set_custom_path( $domain, $path );
 
-	return load_textdomain( $domain, $path . '/' . $mofile, $locale );
+	return true;
 }
 
 /**
@@ -1048,6 +1019,7 @@ function load_plugin_textdomain( $domain, $deprecated = false, $plugin_rel_path
  *
  * @since 3.0.0
  * @since 4.6.0 The function now tries to load the .mo file from the languages directory first.
+ * @since 6.7.0 Translations are no longer immediately loaded, but handed off to the just-in-time loading mechanism.
  *
  * @global WP_Textdomain_Registry $wp_textdomain_registry WordPress Textdomain Registry.
  *
@@ -1064,34 +1036,11 @@ function load_muplugin_textdomain( $domain, $mu_plugin_rel_path = '' ) {
 		return false;
 	}
 
-	if ( ! doing_action( 'after_setup_theme' ) && ! did_action( 'after_setup_theme' ) ) {
-		_doing_it_wrong(
-			__FUNCTION__,
-			sprintf(
-				/* translators: 1: The text domain. 2: 'after_setup_theme'. */
-				__( 'Attempted to load translations for the %1$s domain too early. Translations should be loaded after the %2$s action has fired, to ensure that the current user is already set up.' ),
-				'<code>' . $domain . '</code>',
-				'<code>after_setup_theme</code>'
-			),
-			'6.7.0'
-		);
-	}
-
-	/** This filter is documented in wp-includes/l10n.php */
-	$locale = apply_filters( 'plugin_locale', determine_locale(), $domain );
-
-	$mofile = $domain . '-' . $locale . '.mo';
-
-	// Try to load from the languages directory first.
-	if ( load_textdomain( $domain, WP_LANG_DIR . '/plugins/' . $mofile, $locale ) ) {
-		return true;
-	}
-
 	$path = WPMU_PLUGIN_DIR . '/' . ltrim( $mu_plugin_rel_path, '/' );
 
 	$wp_textdomain_registry->set_custom_path( $domain, $path );
 
-	return load_textdomain( $domain, $path . '/' . $mofile, $locale );
+	return true;
 }
 
 /**
@@ -1104,6 +1053,7 @@ function load_muplugin_textdomain( $domain, $mu_plugin_rel_path = '' ) {
  *
  * @since 1.5.0
  * @since 4.6.0 The function now tries to load the .mo file from the languages directory first.
+ * @since 6.7.0 Translations are no longer immediately loaded, but handed off to the just-in-time loading mechanism.
  *
  * @global WP_Textdomain_Registry $wp_textdomain_registry WordPress Textdomain Registry.
  *
@@ -1120,43 +1070,13 @@ function load_theme_textdomain( $domain, $path = false ) {
 		return false;
 	}
 
-	if ( ! doing_action( 'after_setup_theme' ) && ! did_action( 'after_setup_theme' ) ) {
-		_doing_it_wrong(
-			__FUNCTION__,
-			sprintf(
-				/* translators: 1: The text domain. 2: 'after_setup_theme'. */
-				__( 'Attempted to load translations for the %1$s domain too early. Translations should be loaded after the %2$s action has fired, to ensure that the current user is already set up.' ),
-				'<code>' . $domain . '</code>',
-				'<code>after_setup_theme</code>'
-			),
-			'6.7.0'
-		);
-	}
-
-	/**
-	 * Filters a theme's locale.
-	 *
-	 * @since 3.0.0
-	 *
-	 * @param string $locale The theme's current locale.
-	 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
-	 */
-	$locale = apply_filters( 'theme_locale', determine_locale(), $domain );
-
-	$mofile = $domain . '-' . $locale . '.mo';
-
-	// Try to load from the languages directory first.
-	if ( load_textdomain( $domain, WP_LANG_DIR . '/themes/' . $mofile, $locale ) ) {
-		return true;
-	}
-
 	if ( ! $path ) {
 		$path = get_template_directory();
 	}
 
 	$wp_textdomain_registry->set_custom_path( $domain, $path );
 
-	return load_textdomain( $domain, $path . '/' . $locale . '.mo', $locale );
+	return true;
 }
 
 /**
@@ -1425,9 +1345,10 @@ function _load_textdomain_just_in_time( $domain ) {
 		_doing_it_wrong(
 			__FUNCTION__,
 			sprintf(
-				/* translators: %s: The text domain. */
+				/* translators: 1: The text domain. 2: 'init'. */
-				__( 'Translation loading for the %s domain was triggered too early. This is usually an indicator for some code in the plugin or theme running too early.' ),
+				__( 'Translation loading for the %1$s domain was triggered too early. This is usually an indicator for some code in the plugin or theme running too early. Translations should be loaded at the %2$s action or later.' ),
-				'<code>' . $domain . '</code>'
+				'<code>' . $domain . '</code>',
+				'<code>init</code>'
 			),
 			'6.7.0'
 		);

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.7-beta1-59156';
+$wp_version = '6.7-beta1-59157';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.