diff -r 3d4e9c994f10 -r a86126ab1dd4 wp/wp-includes/l10n.php
--- a/wp/wp-includes/l10n.php	Tue Oct 22 16:11:46 2019 +0200
+++ b/wp/wp-includes/l10n.php	Tue Dec 15 13:49:49 2020 +0100
@@ -22,8 +22,8 @@
  *
  * @since 1.5.0
  *
- * @global string $locale
- * @global string $wp_local_package
+ * @global string $locale           The current locale.
+ * @global string $wp_local_package Locale code of the package.
  *
  * @return string The locale of the blog or from the {@see 'locale'} hook.
  */
@@ -53,16 +53,21 @@
 	// If multisite, check options.
 	if ( is_multisite() ) {
 		// Don't check blog option when installing.
-		if ( wp_installing() || ( false === $ms_locale = get_option( 'WPLANG' ) ) ) {
+		if ( wp_installing() ) {
 			$ms_locale = get_site_option( 'WPLANG' );
+		} else {
+			$ms_locale = get_option( 'WPLANG' );
+			if ( false === $ms_locale ) {
+				$ms_locale = get_site_option( 'WPLANG' );
+			}
 		}
 
-		if ( $ms_locale !== false ) {
+		if ( false !== $ms_locale ) {
 			$locale = $ms_locale;
 		}
 	} else {
 		$db_locale = get_option( 'WPLANG' );
-		if ( $db_locale !== false ) {
+		if ( false !== $db_locale ) {
 			$locale = $db_locale;
 		}
 	}
@@ -121,9 +126,10 @@
 	 *
 	 * @since 5.0.0
 	 *
-	 * @param string|null The locale to return and short-circuit, or null as default.
+	 * @param string|null $locale The locale to return and short-circuit. Default null.
 	 */
 	$determined_locale = apply_filters( 'pre_determine_locale', null );
+
 	if ( ! empty( $determined_locale ) && is_string( $determined_locale ) ) {
 		return $determined_locale;
 	}
@@ -160,11 +166,12 @@
  * *Note:* Don't use translate() directly, use __() or related functions.
  *
  * @since 2.2.0
+ * @since 5.5.0 Introduced gettext-{$domain} filter.
  *
  * @param string $text   Text to translate.
  * @param string $domain Optional. Text domain. Unique identifier for retrieving translated strings.
  *                       Default 'default'.
- * @return string Translated text
+ * @return string Translated text.
  */
 function translate( $text, $domain = 'default' ) {
 	$translations = get_translations_for_domain( $domain );
@@ -175,11 +182,26 @@
 	 *
 	 * @since 2.0.11
 	 *
-	 * @param string $translation  Translated text.
-	 * @param string $text         Text to translate.
-	 * @param string $domain       Text domain. Unique identifier for retrieving translated strings.
+	 * @param string $translation Translated text.
+	 * @param string $text        Text to translate.
+	 * @param string $domain      Text domain. Unique identifier for retrieving translated strings.
 	 */
-	return apply_filters( 'gettext', $translation, $text, $domain );
+	$translation = apply_filters( 'gettext', $translation, $text, $domain );
+
+	/**
+	 * Filters text with its translation for a domain.
+	 *
+	 * The dynamic portion of the hook, `$domain`, refers to the text domain.
+	 *
+	 * @since 5.5.0
+	 *
+	 * @param string $translation Translated text.
+	 * @param string $text        Text to translate.
+	 * @param string $domain      Text domain. Unique identifier for retrieving translated strings.
+	 */
+	$translation = apply_filters( "gettext_{$domain}", $translation, $text, $domain );
+
+	return $translation;
 }
 
 /**
@@ -205,12 +227,12 @@
 /**
  * Retrieve the translation of $text in the context defined in $context.
  *
- * If there is no translation, or the text domain isn't loaded the original
- * text is returned.
+ * If there is no translation, or the text domain isn't loaded, the original text is returned.
  *
  * *Note:* Don't use translate_with_gettext_context() directly, use _x() or related functions.
  *
  * @since 2.8.0
+ * @since 5.5.0 Introduced gettext_with_context-{$domain} filter.
  *
  * @param string $text    Text to translate.
  * @param string $context Context information for the translators.
@@ -221,17 +243,34 @@
 function translate_with_gettext_context( $text, $context, $domain = 'default' ) {
 	$translations = get_translations_for_domain( $domain );
 	$translation  = $translations->translate( $text, $context );
+
 	/**
 	 * Filters text with its translation based on context information.
 	 *
 	 * @since 2.8.0
 	 *
-	 * @param string $translation  Translated text.
-	 * @param string $text         Text to translate.
-	 * @param string $context      Context information for the translators.
-	 * @param string $domain       Text domain. Unique identifier for retrieving translated strings.
+	 * @param string $translation Translated text.
+	 * @param string $text        Text to translate.
+	 * @param string $context     Context information for the translators.
+	 * @param string $domain      Text domain. Unique identifier for retrieving translated strings.
 	 */
-	return apply_filters( 'gettext_with_context', $translation, $text, $context, $domain );
+	$translation = apply_filters( 'gettext_with_context', $translation, $text, $context, $domain );
+
+	/**
+	 * Filters text with its translation based on context information for a domain.
+	 *
+	 * The dynamic portion of the hook, `$domain`, refers to the text domain.
+	 *
+	 * @since 5.5.0
+	 *
+	 * @param string $translation Translated text.
+	 * @param string $text        Text to translate.
+	 * @param string $context     Context information for the translators.
+	 * @param string $domain      Text domain. Unique identifier for retrieving translated strings.
+	 */
+	$translation = apply_filters( "gettext_with_context_{$domain}", $translation, $text, $context, $domain );
+
+	return $translation;
 }
 
 /**
@@ -277,7 +316,7 @@
  * @param string $text   Text to translate.
  * @param string $domain Optional. Text domain. Unique identifier for retrieving translated strings.
  *                       Default 'default'.
- * @return string Translated text
+ * @return string Translated text.
  */
 function esc_html__( $text, $domain = 'default' ) {
 	return esc_html( translate( $text, $domain ) );
@@ -299,6 +338,11 @@
 /**
  * Display translated text that has been escaped for safe use in an attribute.
  *
+ * Encodes `< > & " '` (less than, greater than, ampersand, double quote, single quote).
+ * Will never double encode entities.
+ *
+ * If you need the value for use in PHP, use esc_attr__().
+ *
  * @since 2.8.0
  *
  * @param string $text   Text to translate.
@@ -312,6 +356,11 @@
 /**
  * Display translated text that has been escaped for safe use in HTML output.
  *
+ * If there is no translation, or the text domain isn't loaded, the original text
+ * is escaped and displayed.
+ *
+ * If you need the value for use in PHP, use esc_html__().
+ *
  * @since 2.8.0
  *
  * @param string $text   Text to translate.
@@ -361,13 +410,16 @@
 /**
  * Translate string with gettext context, and escapes it for safe use in an attribute.
  *
+ * If there is no translation, or the text domain isn't loaded, the original text
+ * is escaped and returned.
+ *
  * @since 2.8.0
  *
  * @param string $text    Text to translate.
  * @param string $context Context information for the translators.
  * @param string $domain  Optional. Text domain. Unique identifier for retrieving translated strings.
  *                        Default 'default'.
- * @return string Translated text
+ * @return string Translated text.
  */
 function esc_attr_x( $text, $context, $domain = 'default' ) {
 	return esc_attr( translate_with_gettext_context( $text, $context, $domain ) );
@@ -376,6 +428,9 @@
 /**
  * Translate string with gettext context, and escapes it for safe use in HTML output.
  *
+ * If there is no translation, or the text domain isn't loaded, the original text
+ * is escaped and returned.
+ *
  * @since 2.9.0
  *
  * @param string $text    Text to translate.
@@ -399,6 +454,7 @@
  *     printf( _n( '%s person', '%s people', $count, 'text-domain' ), number_format_i18n( $count ) );
  *
  * @since 2.8.0
+ * @since 5.5.0 Introduced ngettext-{$domain} filter.
  *
  * @param string $single The text to be used if the number is singular.
  * @param string $plural The text to be used if the number is plural.
@@ -422,7 +478,24 @@
 	 * @param string $number      The number to compare against to use either the singular or plural form.
 	 * @param string $domain      Text domain. Unique identifier for retrieving translated strings.
 	 */
-	return apply_filters( 'ngettext', $translation, $single, $plural, $number, $domain );
+	$translation = apply_filters( 'ngettext', $translation, $single, $plural, $number, $domain );
+
+	/**
+	 * Filters the singular or plural form of a string for a domain.
+	 *
+	 * The dynamic portion of the hook, `$domain`, refers to the text domain.
+	 *
+	 * @since 5.5.0
+	 *
+	 * @param string $translation Translated text.
+	 * @param string $single      The text to be used if the number is singular.
+	 * @param string $plural      The text to be used if the number is plural.
+	 * @param string $number      The number to compare against to use either the singular or plural form.
+	 * @param string $domain      Text domain. Unique identifier for retrieving translated strings.
+	 */
+	$translation = apply_filters( "ngettext_{$domain}", $translation, $single, $plural, $number, $domain );
+
+	return $translation;
 }
 
 /**
@@ -439,6 +512,7 @@
  *     printf( _nx( '%s group', '%s groups', $animals, 'group of animals', 'text-domain' ), number_format_i18n( $animals ) );
  *
  * @since 2.8.0
+ * @since 5.5.0 Introduced ngettext_with_context-{$domain} filter.
  *
  * @param string $single  The text to be used if the number is singular.
  * @param string $plural  The text to be used if the number is plural.
@@ -464,7 +538,25 @@
 	 * @param string $context     Context information for the translators.
 	 * @param string $domain      Text domain. Unique identifier for retrieving translated strings.
 	 */
-	return apply_filters( 'ngettext_with_context', $translation, $single, $plural, $number, $context, $domain );
+	$translation = apply_filters( 'ngettext_with_context', $translation, $single, $plural, $number, $context, $domain );
+
+	/**
+	 * Filters the singular or plural form of a string with gettext context for a domain.
+	 *
+	 * The dynamic portion of the hook, `$domain`, refers to the text domain.
+	 *
+	 * @since 5.5.0
+	 *
+	 * @param string $translation Translated text.
+	 * @param string $single      The text to be used if the number is singular.
+	 * @param string $plural      The text to be used if the number is plural.
+	 * @param string $number      The number to compare against to use either the singular or plural form.
+	 * @param string $context     Context information for the translators.
+	 * @param string $domain      Text domain. Unique identifier for retrieving translated strings.
+	 */
+	$translation = apply_filters( "ngettext_with_context_{$domain}", $translation, $single, $plural, $number, $context, $domain );
+
+	return $translation;
 }
 
 /**
@@ -620,7 +712,7 @@
 	 */
 	$plugin_override = apply_filters( 'override_load_textdomain', false, $domain, $mofile );
 
-	if ( true == $plugin_override ) {
+	if ( true === (bool) $plugin_override ) {
 		unset( $l10n_unloaded[ $domain ] );
 
 		return true;
@@ -906,8 +998,7 @@
  * @param string $handle Name of the script to register a translation domain to.
  * @param string $domain Optional. Text domain. Default 'default'.
  * @param string $path   Optional. The full file path to the directory containing translation files.
- *
- * @return false|string False if the script textdomain could not be loaded, the translated strings
+ * @return string|false False if the script textdomain could not be loaded, the translated strings
  *                      in JSON encoding otherwise.
  */
 function load_script_textdomain( $handle, $domain = 'default', $path = null ) {
@@ -921,7 +1012,7 @@
 	$locale = determine_locale();
 
 	// If a path was given and the handle file exists simply return it.
-	$file_base       = $domain === 'default' ? $locale : $domain . '-' . $locale;
+	$file_base       = 'default' === $domain ? $locale : $domain . '-' . $locale;
 	$handle_filename = $file_base . '-' . $handle . '.json';
 
 	if ( $path ) {
@@ -943,20 +1034,43 @@
 
 	$src_url     = wp_parse_url( $src );
 	$content_url = wp_parse_url( content_url() );
+	$plugins_url = wp_parse_url( plugins_url() );
 	$site_url    = wp_parse_url( site_url() );
 
 	// If the host is the same or it's a relative URL.
 	if (
-		strpos( $src_url['path'], $content_url['path'] ) === 0 &&
+		( ! isset( $content_url['path'] ) || strpos( $src_url['path'], $content_url['path'] ) === 0 ) &&
 		( ! isset( $src_url['host'] ) || $src_url['host'] === $content_url['host'] )
 	) {
 		// Make the src relative the specific plugin or theme.
-		$relative = trim( substr( $src_url['path'], strlen( $content_url['path'] ) ), '/' );
+		if ( isset( $content_url['path'] ) ) {
+			$relative = substr( $src_url['path'], strlen( $content_url['path'] ) );
+		} else {
+			$relative = $src_url['path'];
+		}
+		$relative = trim( $relative, '/' );
 		$relative = explode( '/', $relative );
 
 		$languages_path = WP_LANG_DIR . '/' . $relative[0];
 
-		$relative = array_slice( $relative, 2 );
+		$relative = array_slice( $relative, 2 ); // Remove plugins/<plugin name> or themes/<theme name>.
+		$relative = implode( '/', $relative );
+	} elseif (
+		( ! isset( $plugins_url['path'] ) || strpos( $src_url['path'], $plugins_url['path'] ) === 0 ) &&
+		( ! isset( $src_url['host'] ) || $src_url['host'] === $plugins_url['host'] )
+	) {
+		// Make the src relative the specific plugin.
+		if ( isset( $plugins_url['path'] ) ) {
+			$relative = substr( $src_url['path'], strlen( $plugins_url['path'] ) );
+		} else {
+			$relative = $src_url['path'];
+		}
+		$relative = trim( $relative, '/' );
+		$relative = explode( '/', $relative );
+
+		$languages_path = WP_LANG_DIR . '/plugins';
+
+		$relative = array_slice( $relative, 1 ); // Remove <plugin name>.
 		$relative = implode( '/', $relative );
 	} elseif ( ! isset( $src_url['host'] ) || $src_url['host'] === $site_url['host'] ) {
 		if ( ! isset( $site_url['path'] ) ) {
@@ -973,8 +1087,8 @@
 	 *
 	 * @since 5.0.2
 	 *
-	 * @param string $relative The relative path of the script. False if it could not be determined.
-	 * @param string $src      The full source url of the script.
+	 * @param string|false $relative The relative path of the script. False if it could not be determined.
+	 * @param string       $src      The full source URL of the script.
 	 */
 	$relative = apply_filters( 'load_script_textdomain_relative_path', $relative, $src );
 
@@ -1025,10 +1139,10 @@
 	 *
 	 * @since 5.0.2
 	 *
-	 * @param string|false $translations JSON-encoded translation data. Default null.
-	 * @param string|false $file         Path to the translation file to load. False if there isn't one.
-	 * @param string       $handle       Name of the script to register a translation domain to.
-	 * @param string       $domain       The text domain.
+	 * @param string|false|null $translations JSON-encoded translation data. Default null.
+	 * @param string|false      $file         Path to the translation file to load. False if there isn't one.
+	 * @param string            $handle       Name of the script to register a translation domain to.
+	 * @param string            $domain       The text domain.
 	 */
 	$translations = apply_filters( 'pre_load_script_translations', null, $file, $handle, $domain );
 
@@ -1109,7 +1223,6 @@
  * @access private
  *
  * @see _load_textdomain_just_in_time()
- * @staticvar array $available_translations
  *
  * @param string $domain Text domain. Unique identifier for retrieving translated strings.
  * @param bool   $reset  Whether to reset the internal cache. Used by the switch to locale functionality.
@@ -1138,7 +1251,6 @@
  * @access private
  *
  * @see _get_path_to_translation()
- * @staticvar array $cached_mofiles
  *
  * @param string $domain Text domain. Unique identifier for retrieving translated strings.
  * @return string|false The path to the translation file or false if no translation file was found.
@@ -1166,12 +1278,12 @@
 	$mofile = "{$domain}-{$locale}.mo";
 
 	$path = WP_LANG_DIR . '/plugins/' . $mofile;
-	if ( in_array( $path, $cached_mofiles ) ) {
+	if ( in_array( $path, $cached_mofiles, true ) ) {
 		return $path;
 	}
 
 	$path = WP_LANG_DIR . '/themes/' . $mofile;
-	if ( in_array( $path, $cached_mofiles ) ) {
+	if ( in_array( $path, $cached_mofiles, true ) ) {
 		return $path;
 	}
 
@@ -1186,7 +1298,6 @@
  * @since 2.8.0
  *
  * @global MO[] $l10n
- * @staticvar NOOP_Translations $noop_translations
  *
  * @param string $domain Text domain. Unique identifier for retrieving translated strings.
  * @return Translations|NOOP_Translations A Translations instance.
@@ -1254,7 +1365,7 @@
  *
  * @param string $dir A directory to search for language files.
  *                    Default WP_LANG_DIR.
- * @return array An array of language codes or an empty array if no languages are present. Language codes are formed by stripping the .mo extension from the language file names.
+ * @return string[] An array of language codes or an empty array if no languages are present. Language codes are formed by stripping the .mo extension from the language file names.
  */
 function get_available_languages( $dir = null ) {
 	$languages = array();
@@ -1275,8 +1386,8 @@
 	 *
 	 * @since 4.7.0
 	 *
-	 * @param array  $languages An array of available language codes.
-	 * @param string $dir       The directory where the language files were found.
+	 * @param string[] $languages An array of available language codes.
+	 * @param string   $dir       The directory where the language files were found.
 	 */
 	return apply_filters( 'get_available_languages', $languages, $dir );
 }
@@ -1293,7 +1404,7 @@
  * @return array Array of language data.
  */
 function wp_get_installed_translations( $type ) {
-	if ( $type !== 'themes' && $type !== 'plugins' && $type !== 'core' ) {
+	if ( 'themes' !== $type && 'plugins' !== $type && 'core' !== $type ) {
 		return array();
 	}
 
@@ -1324,7 +1435,7 @@
 		if ( ! preg_match( '/(?:(.+)-)?([a-z]{2,3}(?:_[A-Z]{2})?(?:_[a-z0-9]+)?).po/', $file, $match ) ) {
 			continue;
 		}
-		if ( ! in_array( substr( $file, 0, -3 ) . '.mo', $files ) ) {
+		if ( ! in_array( substr( $file, 0, -3 ) . '.mo', $files, true ) ) {
 			continue;
 		}
 
@@ -1343,7 +1454,7 @@
  * @since 3.7.0
  *
  * @param string $po_file Path to PO file.
- * @return array PO file headers.
+ * @return string[] Array of PO file header values keyed by header name.
  */
 function wp_get_pomo_file_data( $po_file ) {
 	$headers = get_file_data(
@@ -1389,7 +1500,7 @@
  *     @type bool     $show_option_site_default     Whether to show an option to fall back to the site's locale. Default false.
  *     @type bool     $show_option_en_us            Whether to show an option for English (United States). Default true.
  * }
- * @return string HTML content
+ * @return string HTML dropdown list of languages.
  */
 function wp_dropdown_languages( $args = array() ) {
 
@@ -1420,7 +1531,7 @@
 
 	$translations = $parsed_args['translations'];
 	if ( empty( $translations ) ) {
-		require_once( ABSPATH . 'wp-admin/includes/translation-install.php' );
+		require_once ABSPATH . 'wp-admin/includes/translation-install.php';
 		$translations = wp_get_available_translations();
 	}
 
@@ -1525,7 +1636,7 @@
  *
  * @since 3.0.0
  *
- * @global WP_Locale $wp_locale
+ * @global WP_Locale $wp_locale WordPress date and time locale object.
  *
  * @return bool Whether locale is RTL.
  */
@@ -1542,7 +1653,7 @@
  *
  * @since 4.7.0
  *
- * @global WP_Locale_Switcher $wp_locale_switcher
+ * @global WP_Locale_Switcher $wp_locale_switcher WordPress locale switcher object.
  *
  * @param string $locale The locale.
  * @return bool True on success, false on failure.
@@ -1559,7 +1670,7 @@
  *
  * @since 4.7.0
  *
- * @global WP_Locale_Switcher $wp_locale_switcher
+ * @global WP_Locale_Switcher $wp_locale_switcher WordPress locale switcher object.
  *
  * @return string|false Locale on success, false on error.
  */
@@ -1575,7 +1686,7 @@
  *
  * @since 4.7.0
  *
- * @global WP_Locale_Switcher $wp_locale_switcher
+ * @global WP_Locale_Switcher $wp_locale_switcher WordPress locale switcher object.
  *
  * @return string|false Locale on success, false on error.
  */
@@ -1591,7 +1702,7 @@
  *
  * @since 4.7.0
  *
- * @global WP_Locale_Switcher $wp_locale_switcher
+ * @global WP_Locale_Switcher $wp_locale_switcher WordPress locale switcher object.
  *
  * @return bool True if the locale has been switched, false otherwise.
  */