Collation: Workaround for incorrect collation of Estonian

'W' and 'V' should not be considered the same letter for the purposes
of collation in modern Estonian. We work around this by replacing 'W'
and 'w' with 'ᴡ' U+1D21 'LATIN LETTER SMALL CAPITAL W' for sortkey
generation, which is collated like 'W' and is not tailored to have the
same primary weight as 'V' in Estonian.

Bug: 54168
Change-Id: I3e8031b9d1dc18fdb7595fb9fd23e5f930106fa4

diff --git a/includes/AutoLoader.php b/includes/AutoLoader.php
index 127f2cd..9b1dfc6 100644 (file)
--- a/includes/AutoLoader.php
+++ b/includes/AutoLoader.php
@@ -45,6 +45,7 @@ $wgAutoloadLocalClasses = array(
        'ChannelFeed' => 'includes/Feed.php',
        'Collation' => 'includes/Collation.php',
        'CollationCkb' => 'includes/Collation.php',
+       'CollationEt' => 'includes/Collation.php',
        'ConcatenatedGzipHistoryBlob' => 'includes/HistoryBlob.php',
        'Cookie' => 'includes/Cookie.php',
        'CookieJar' => 'includes/Cookie.php',

diff --git a/includes/Collation.php b/includes/Collation.php
index 71adb09..bcb0a56 100644 (file)
--- a/includes/Collation.php
+++ b/includes/Collation.php
@@ -49,6 +49,8 @@ abstract class Collation {
                                return new IcuCollation( 'root' );
                        case 'xx-uca-ckb':
                                return new CollationCkb;
+                       case 'xx-uca-et':
+                               return new CollationEt;
                        default:
                                $match = array();
                                if ( preg_match( '/^uca-([a-z@=-]+)$/', $collationName, $match ) ) {
@@ -253,7 +255,7 @@ class IcuCollation extends Collation {
                'el' => array(),
                'eo' => array( "Ĉ", "Ĝ", "Ĥ", "Ĵ", "Ŝ", "Ŭ" ),
                'es' => array( "Ñ" ),
-               'et' => array( "Š", "Ž", "Õ", "Ä", "Ö", "Ü" ),
+               'et' => array( "Š", "Ž", "Õ", "Ä", "Ö", "Ü", "W" ), // added W for CollationEt (xx-uca-et)
                'eu' => array( "Ñ" ),
                'fo' => array( "Á", "Ð", "Í", "Ó", "Ú", "Ý", "Æ", "Ø", "Å" ),
                'fur' => array( "À", "Á", "Â", "È", "Ì", "Ò", "Ù" ),
@@ -597,3 +599,42 @@ class CollationCkb extends IcuCollation {
                $this->digitTransformLanguage = Language::factory( 'ckb' );
        }
 }
+
+/**
+ * Workaround for incorrect collation of Estonian language ('et') in ICU (bug 54168).
+ *
+ * 'W' and 'V' should not be considered the same letter for the purposes of collation in modern
+ * Estonian. We work around this by replacing 'W' and 'w' with 'ᴡ' U+1D21 'LATIN LETTER SMALL
+ * CAPITAL W' for sortkey generation, which is collated like 'W' and is not tailored to have the
+ * same primary weight as 'V' in Estonian.
+ */
+class CollationEt extends IcuCollation {
+       function __construct() {
+               parent::__construct( 'et' );
+       }
+
+       private static function mangle( $string ) {
+               return str_replace(
+                       array( 'w', 'W' ),
+                       'ᴡ', // U+1D21 'LATIN LETTER SMALL CAPITAL W'
+                       $string
+               );
+       }
+
+       private static function unmangle( $string ) {
+               // Casing data is lost…
+               return str_replace(
+                       'ᴡ', // U+1D21 'LATIN LETTER SMALL CAPITAL W'
+                       'W',
+                       $string
+               );
+       }
+
+       function getSortKey( $string ) {
+               return parent::getSortKey( self::mangle( $string ) );
+       }
+
+       function getFirstLetter( $string ) {
+               return self::unmangle( parent::getFirstLetter( self::mangle( $string ) ) );
+       }
+}