Revert r51128, and its follow-up revisions r51129, r51130, r51390.

Commit message was: "* (bug 18958) Added ability to disable entire variant conversion engine per user preferences (languages with language converter class only)"
Reverted because of multiple issues on CodeReview, notably:
* Unexplained rename of a configuration variable, with no backwards-compatibility code.
* Suspected parser cache pollution.
* Variant tabs flip-flop with parser cache misses and hits.
* Hacky implementation: changing configuration variables on the fly is almost always a bad idea, unless you are writing a configuration extension.
* Implementation of default is done as a special case in code accessing the preference, rather than by adding an entry to $wgDefaultUserOptions.

26 files changed, 51 insertions, 50 deletions

diff --git a/RELEASE-NOTES b/RELEASE-NOTES
index 9b96db73e2ac..bde9ae9d4cd8 100644
--- a/RELEASE-NOTES
+++ b/RELEASE-NOTES
@@ -32,9 +32,6 @@ it from source control: http://www.mediawiki.org/wiki/Download_from_SVN
 * (bug 9257) $wgRCMaxAge now defaults to three months
 * $wgDevelopmentWarnings can be set to true to show warnings about deprecated
   functions and other potential errors when developing.
-* (bug 18958) $wgEnableVariants is a new boolean value to turn on or off the
-  entire variant conversion engine, and the default is set to true. Former
-  variable $wgDisableLangConversion was superseded by this variable.
 * Subpages are now enabled in the MediaWiki namespace by default.  This is
   mainly a cosmetic change, and does not in any way affect the MessageCache,
   which was already effectively treating the namespace as if it had subpages.
@@ -77,8 +74,6 @@ it from source control: http://www.mediawiki.org/wiki/Download_from_SVN
 * (bug 18860) Blocks of IPs affecting registered users can now block email
 * (bug 17093) Date and time are separate parameters in Special:BlockList
 * (bug 11484) Added ISO speed rating to default collapsed EXIF metadata view
-* (bug 18958) Added ability to disable entire variant conversion engine
-  per user preferences
 * (bug 19012) Introduce {{NUMBEROFCONTRIBS}} variable to display the number
   of contributions a user has.
 * (bug 14866) Messages 'recentchangeslinked-toolbox' and
diff --git a/includes/DefaultSettings.php b/includes/DefaultSettings.php
index 13f9b26211e9..d0d719a3b9dc 100644
--- a/includes/DefaultSettings.php
+++ b/includes/DefaultSettings.php
@@ -887,7 +887,7 @@ $wgEnableSerializedMessages = true;
 $wgCheckSerialized = true;
 
 /** Whether to enable language variant conversion. */
-$wgEnableVariants = true;
+$wgDisableLangConversion = false;
 
 /** Whether to enable language variant conversion for links. */
 $wgDisableTitleConversion = false;
diff --git a/includes/Preferences.php b/includes/Preferences.php
index 65f0722549b0..5f64f27aef17 100644
--- a/includes/Preferences.php
+++ b/includes/Preferences.php
@@ -215,10 +215,10 @@ class Preferences {
 					'label-message' => 'yourlanguage',
 				);
 				
-		global $wgContLang, $wgEnableVariants;
+		global $wgContLang, $wgDisableLangConversion;
 		/* see if there are multiple language variants to choose from*/
 		$variantArray = array();
-		if($wgEnableVariants) {
+		if(!$wgDisableLangConversion) {
 			$variants = $wgContLang->getVariants();
 
 			$languages = Language::getLanguageNames( true );
@@ -247,7 +247,7 @@ class Preferences {
 			}
 		}
 		
-		if( count($variantArray) > 1 && $wgEnableVariants && !$wgDisableTitleConversion ) {
+		if( count($variantArray) > 1 && !$wgDisableLangConversion && !$wgDisableTitleConversion ) {
 			$defaultPreferences['noconvertlink'] =
 					array(
 						'type' => 'toggle',
diff --git a/includes/Skin.php b/includes/Skin.php
index 45000fd748c7..1e3a9fb117ab 100644
--- a/includes/Skin.php
+++ b/includes/Skin.php
@@ -1272,9 +1272,9 @@ END;
 	function variantLinks() {
 		$s = '';
 		/* show links to different language variants */
-		global $wgEnableVariants, $wgLang, $wgContLang;
+		global $wgDisableLangConversion, $wgLang, $wgContLang;
 		$variants = $wgContLang->getVariants();
-		if( $wgEnableVariants && sizeof( $variants ) > 1 ) {
+		if( !$wgDisableLangConversion && sizeof( $variants ) > 1 ) {
 			foreach( $variants as $code ) {
 				$varname = $wgContLang->getVariantname( $code );
 				if( $varname == 'disable' )
diff --git a/includes/SkinTemplate.php b/includes/SkinTemplate.php
index a08d2fb97b8c..dcbedd881668 100644
--- a/includes/SkinTemplate.php
+++ b/includes/SkinTemplate.php
@@ -819,9 +819,9 @@ class SkinTemplate extends Skin {
 		}
 
 		/* show links to different language variants */
-		global $wgEnableVariants;
+		global $wgDisableLangConversion;
 		$variants = $wgContLang->getVariants();
-		if( $wgEnableVariants && sizeof( $variants ) > 1 ) {
+		if( !$wgDisableLangConversion && sizeof( $variants ) > 1 ) {
 			$preferred = $wgContLang->getPreferredVariant();
 			$vcount=0;
 			foreach( $variants as $code ) {
@@ -1107,4 +1107,4 @@ class QuickTemplate {
 		$msg = $this->translator->translate( $str );
 		return ( $msg != '-' ) && ( $msg != '' ); # ????
 	}
-}
+}
\ No newline at end of file
diff --git a/languages/LanguageConverter.php b/languages/LanguageConverter.php
index dbdde9c5c86e..57af7bcab13b 100644
--- a/languages/LanguageConverter.php
+++ b/languages/LanguageConverter.php
@@ -425,14 +425,7 @@ class LanguageConverter {
 	 * @public
 	 */
 	function parserConvert( $text, &$parser ) {
-		global $wgUser, $wgEnableVariants;
-
-		/* disable entire conversion engine if the user had been disabled it */
-		$variantConv = $wgUser->getOption( 'variantconversion' );
-		if ( ( $wgEnableVariants == true ) && ( $variantConv === 0 ) ) { 
-			$wgEnableVariants = false;
-		}
-
+		global $wgDisableLangConversion;
 		/* don't do anything if this is the conversion table */
 		if ( $parser->getTitle()->getNamespace() == NS_MEDIAWIKI &&
 				 strpos($parser->mTitle->getText(), "Conversiontable") !== false ) 
@@ -440,7 +433,7 @@ class LanguageConverter {
 			return $text;
 		}
 
-		if ( !$wgEnableVariants )
+		if ( $wgDisableLangConversion )
 			return $text;
 
 		$text = $this->convert( $text );
@@ -579,11 +572,11 @@ class LanguageConverter {
 	 * @public
 	 */
 	function findVariantLink( &$link, &$nt, $ignoreOtherCond = false ) {
-		global $wgEnableVariants, $wgDisableTitleConversion, $wgRequest, $wgUser;
+		global $wgDisableLangConversion, $wgDisableTitleConversion, $wgRequest, $wgUser;
 		$isredir = $wgRequest->getText( 'redirect', 'yes' );
 		$action = $wgRequest->getText( 'action' );
 		$linkconvert = $wgRequest->getText( 'linkconvert', 'yes' );
-		$disableLinkConversion = !$wgEnableVariants || $wgDisableTitleConversion;
+		$disableLinkConversion = $wgDisableLangConversion || $wgDisableTitleConversion;
 		$linkBatch = new LinkBatch();
 
 		$ns=NS_MAIN;
diff --git a/languages/messages/MessagesEn.php b/languages/messages/MessagesEn.php
index 4bf31cad3bf2..39fefda62ae7 100644
--- a/languages/messages/MessagesEn.php
+++ b/languages/messages/MessagesEn.php
@@ -538,7 +538,7 @@ XHTML id names.
 'tog-watchlisthideliu'        => 'Hide edits by logged in users from the watchlist',
 'tog-watchlisthideanons'      => 'Hide edits by anonymous users from the watchlist',
 'tog-watchlisthidepatrolled'  => 'Hide patrolled edits from the watchlist',
-'tog-variantconversion'       => 'Enable variants conversion', # only translate this message to other languages if you have to change it
+'tog-nolangconversion'        => 'Disable variants conversion', # only translate this message to other languages if you have to change it
 'tog-ccmeonemails'            => 'Send me copies of e-mails I send to other users',
 'tog-diffonly'                => 'Do not show page content below diffs',
 'tog-showhiddencats'          => 'Show hidden categories',
diff --git a/languages/messages/MessagesGan_hans.php b/languages/messages/MessagesGan_hans.php
index 57d3e7afe8ce..84d31363bff7 100644
--- a/languages/messages/MessagesGan_hans.php
+++ b/languages/messages/MessagesGan_hans.php
@@ -64,7 +64,7 @@ $messages = array(
 'tog-watchlisthideown'        => '监视列表弆到偶𠮶编辑',
 'tog-watchlisthidebots'       => '监视列表弆到机器人𠮶编辑',
 'tog-watchlisthideminor'      => '监视列表弆到细修改',
-'tog-variantconversion'       => '要字转换',
+'tog-nolangconversion'        => '嫑字转换',
 'tog-ccmeonemails'            => '偶发email到人家时也发封副本到偶',
 'tog-diffonly'                => '比较两只版本差异𠮶时间伓显示文章𠮶内容',
 'tog-showhiddencats'          => '显示弆到𠮶分类',
diff --git a/languages/messages/MessagesGan_hant.php b/languages/messages/MessagesGan_hant.php
index c7eaee3453ce..e20b23dd1266 100644
--- a/languages/messages/MessagesGan_hant.php
+++ b/languages/messages/MessagesGan_hant.php
@@ -89,7 +89,7 @@ $messages = array(
 'tog-watchlisthideown'        => '監視列表弆到偶嗰編輯',
 'tog-watchlisthidebots'       => '監視列表弆到機器人嗰編輯',
 'tog-watchlisthideminor'      => '監視列表弆到細修改',
-'tog-variantconversion'       => '要字轉換',
+'tog-nolangconversion'        => '嫑字轉換',
 'tog-ccmeonemails'            => '偶發email到人家時也發封副本到偶',
 'tog-diffonly'                => '比較兩隻版本差異嗰時間伓顯示文章嗰內容',
 'tog-showhiddencats'          => '顯示弆到嗰分類',
diff --git a/languages/messages/MessagesJa.php b/languages/messages/MessagesJa.php
index d3d6b5b2c22a..cd711856a807 100644
--- a/languages/messages/MessagesJa.php
+++ b/languages/messages/MessagesJa.php
@@ -318,7 +318,7 @@ $messages = array(
 'tog-watchlisthideliu'        => 'ウォッチリストにログイン利用者の編集を表示しない',
 'tog-watchlisthideanons'      => 'ウォッチリストに匿名利用者の編集を表示しない',
 'tog-watchlisthidepatrolled'  => 'ウォッチリストにパトロール済みの編集を表示しない',
-'tog-variantconversion'       => '言語変種変換を有効にする',
+'tog-nolangconversion'        => '言語変種変換を無効にする',
 'tog-ccmeonemails'            => '他の利用者に送信したメールの控えを自分にも送る',
 'tog-diffonly'                => '差分表示の下に記事本文を表示しない',
 'tog-showhiddencats'          => '隠しカテゴリを表示する',
diff --git a/languages/messages/MessagesKk.php b/languages/messages/MessagesKk.php
index a56193789f89..b0773ea06ea0 100644
--- a/languages/messages/MessagesKk.php
+++ b/languages/messages/MessagesKk.php
@@ -13,10 +13,6 @@
 
 $fallback = 'kk-cyrl';
 
-$extraUserToggles = array(
-	'variantconversion'
-);
-
 $messages = array(
 # Edit pages
 'edittools' => '<!-- Мындағы мәтін өңдеу және қотару пішіндердің астында көрсетіледі. -->',
diff --git a/languages/messages/MessagesKk_arab.php b/languages/messages/MessagesKk_arab.php
index 546587ba1285..875b3b7c05f2 100644
--- a/languages/messages/MessagesKk_arab.php
+++ b/languages/messages/MessagesKk_arab.php
@@ -51,6 +51,10 @@ $defaultUserOptionOverrides = array(
 	'underline' => 0,
 );
 
+$extraUserToggles = array(
+	'nolangconversion'
+);
+
 $fallback8bitEncoding = 'windows-1256';
 
 $namespaceNames = array(
diff --git a/languages/messages/MessagesKk_cyrl.php b/languages/messages/MessagesKk_cyrl.php
index c02c807ef09c..aea7915d5691 100644
--- a/languages/messages/MessagesKk_cyrl.php
+++ b/languages/messages/MessagesKk_cyrl.php
@@ -27,6 +27,10 @@ $separatorTransformTable = array(
 	'.' => ',',
 );
 
+$extraUserToggles = array(
+	'nolangconversion'
+);
+
 $fallback8bitEncoding = 'windows-1251';
 
 $namespaceNames = array(
diff --git a/languages/messages/MessagesKk_latn.php b/languages/messages/MessagesKk_latn.php
index 384c718a6f71..78a1b359a53c 100644
--- a/languages/messages/MessagesKk_latn.php
+++ b/languages/messages/MessagesKk_latn.php
@@ -31,6 +31,10 @@ $separatorTransformTable = array(
 	'.' => ',',
 );
 
+$extraUserToggles = array(
+	'nolangconversion'
+);
+
 $fallback8bitEncoding = 'windows-1254';
 
 $namespaceNames = array(
diff --git a/languages/messages/MessagesLzh.php b/languages/messages/MessagesLzh.php
index 031ea3292400..1bd6c82816bd 100644
--- a/languages/messages/MessagesLzh.php
+++ b/languages/messages/MessagesLzh.php
@@ -106,7 +106,7 @@ $messages = array(
 'tog-watchlisthideliu'        => '不哨有簿',
 'tog-watchlisthideanons'      => '不哨無簿',
 'tog-watchlisthidepatrolled'  => '不哨已巡',
-'tog-variantconversion'       => '轉',
+'tog-nolangconversion'        => '非轉',
 'tog-ccmeonemails'            => '凡所遺書，請存副本。',
 'tog-diffonly'                => '異下無示頁',
 'tog-showhiddencats'          => '示隱類',
diff --git a/languages/messages/MessagesQqq.php b/languages/messages/MessagesQqq.php
index a591b4f36757..584642eb1567 100644
--- a/languages/messages/MessagesQqq.php
+++ b/languages/messages/MessagesQqq.php
@@ -127,7 +127,7 @@ This is the toolbar: [[Image:Toolbar.png]]",
 'tog-watchlisthideliu'        => "Option in tab 'Watchlist' of [[Special:Preferences]]",
 'tog-watchlisthideanons'      => "Option in tab 'Watchlist' of [[Special:Preferences]]",
 'tog-watchlisthidepatrolled'  => 'Option in Watchlist tab of [[Special:Preferences]]',
-'tog-variantconversion'       => 'In user preferences.',
+'tog-nolangconversion'        => 'In user preferences.',
 'tog-ccmeonemails'            => 'In user preferences',
 'tog-diffonly'                => 'Toggle option used in [[Special:Preferences]].',
 'tog-showhiddencats'          => 'Toggle option used in [[Special:Preferences]].',
diff --git a/languages/messages/MessagesSr.php b/languages/messages/MessagesSr.php
index 48197df26980..03a0c93365c9 100644
--- a/languages/messages/MessagesSr.php
+++ b/languages/messages/MessagesSr.php
@@ -14,10 +14,6 @@
 $fallback = 'sr-ec';
 $linkTrail = '/^([abvgdđežzijklljmnnjoprstćufhcčdžšабвгдђежзијклљмнњопрстћуфхцчџш]+)(.*)$/usD';
 
-$extraUserToggles = array(
-	'variantconversion',
-);
-
 $messages = array(
 # Special:LinkSearch
 'linksearch'       => 'Претрага интернет веза',
diff --git a/languages/messages/MessagesSr_ec.php b/languages/messages/MessagesSr_ec.php
index 15da955d1308..ab092224461c 100644
--- a/languages/messages/MessagesSr_ec.php
+++ b/languages/messages/MessagesSr_ec.php
@@ -58,6 +58,11 @@ $namespaceAliases = array(
 	'Razgovor_o_kategoriji'   => NS_CATEGORY_TALK,
 );
 
+
+$extraUserToggles = array(
+	'nolangconversion',
+);
+
 $datePreferenceMigrationMap = array(
 	'default',
 	'hh:mm d. month y.',
diff --git a/languages/messages/MessagesSr_el.php b/languages/messages/MessagesSr_el.php
index 8d7e228f9f31..18e29c9e6aec 100644
--- a/languages/messages/MessagesSr_el.php
+++ b/languages/messages/MessagesSr_el.php
@@ -52,6 +52,11 @@ $namespaceAliases = array(
 	'Разговор_о_категорији'   => NS_CATEGORY_TALK,
 );
 
+
+$extraUserToggles = array(
+	'nolangconversion',
+);
+
 $datePreferenceMigrationMap = array(
 	'default',
 	'hh:mm d. month y.',
diff --git a/languages/messages/MessagesYue.php b/languages/messages/MessagesYue.php
index 0dda6a18a440..641fae2c8820 100644
--- a/languages/messages/MessagesYue.php
+++ b/languages/messages/MessagesYue.php
@@ -180,7 +180,7 @@ $messages = array(
 'tog-watchlisthideliu'        => '響監視清單度隱藏登入用戶',
 'tog-watchlisthideanons'      => '響監視清單度隱藏匿名用戶',
 'tog-watchlisthidepatrolled'  => '響監視清單度隱藏巡查過嘅編輯',
-'tog-variantconversion'       => '要用字轉換',
+'tog-nolangconversion'        => '唔要用字轉換',
 'tog-ccmeonemails'            => '當我寄電郵畀其他人嗰陣寄返封副本畀我',
 'tog-diffonly'                => '響差異下面唔顯示頁面內容',
 'tog-showhiddencats'          => '顯示隱藏類',
diff --git a/languages/messages/MessagesZh.php b/languages/messages/MessagesZh.php
index d044205641c5..a5fe1a1cfbd0 100644
--- a/languages/messages/MessagesZh.php
+++ b/languages/messages/MessagesZh.php
@@ -170,10 +170,6 @@ $specialPageAliases = array(
 	'DeletedContributions'      => array( '已删除的用户贡献', '已刪除的用戶貢獻' ),
 );
 
-$extraUserToggles = array(
-	'variantconversion',
-);
-
 $messages = array(
 # User preference toggles
 'tog-norollbackdiff' => '進行回退後略過差異比較',
diff --git a/languages/messages/MessagesZh_hans.php b/languages/messages/MessagesZh_hans.php
index 06c00e4315e6..6315fa2730b6 100644
--- a/languages/messages/MessagesZh_hans.php
+++ b/languages/messages/MessagesZh_hans.php
@@ -161,6 +161,9 @@ $specialPageAliases = array(
 	'Tags'                      => array( '标签' ),
 );
 
+$extraUserToggles = array(
+	'nolangconversion',
+);
 $datePreferences = array(
 	'default',
 	'ISO 8601',
@@ -226,7 +229,7 @@ $messages = array(
 'tog-watchlisthideliu'        => '在监视列表中隐藏登录用户',
 'tog-watchlisthideanons'      => '在监视列表中隐藏匿名用户',
 'tog-watchlisthidepatrolled'  => '在监视列表中隐藏已巡查的编辑',
-'tog-variantconversion'       => '进行字词转换',
+'tog-nolangconversion'        => '不进行字词转换',
 'tog-ccmeonemails'            => '把我发送给其他用户的邮件同时发送副本给我自己',
 'tog-diffonly'                => '在比较两个修订版本差异时不显示页面内容',
 'tog-showhiddencats'          => '显示隐藏分类',
diff --git a/languages/messages/MessagesZh_hant.php b/languages/messages/MessagesZh_hant.php
index 6b794171db56..bcd276f036b4 100644
--- a/languages/messages/MessagesZh_hant.php
+++ b/languages/messages/MessagesZh_hant.php
@@ -204,7 +204,7 @@ $messages = array(
 'tog-watchlisthideliu'        => '監視列表中隱藏登入用戶',
 'tog-watchlisthideanons'      => '監視列表中隱藏匿名用戶',
 'tog-watchlisthidepatrolled'  => '監視清單中隱藏已巡查的編輯',
-'tog-variantconversion'       => '進行用字轉換',
+'tog-nolangconversion'        => '不進行用字轉換',
 'tog-ccmeonemails'            => '當我寄電子郵件給其他用戶時，也寄一份複本到我的信箱。',
 'tog-diffonly'                => '在比較兩個修訂版本差異時不顯示頁面內容',
 'tog-showhiddencats'          => '顯示隱藏分類',
diff --git a/maintenance/language/messageTypes.inc b/maintenance/language/messageTypes.inc
index da7b38511f97..2e3d2cf95b7d 100644
--- a/maintenance/language/messageTypes.inc
+++ b/maintenance/language/messageTypes.inc
@@ -165,7 +165,7 @@ $wgOptionalMessages = array(
 	'sectionlink',
 	'unit-pixel',
 	'userrights-irreversible-marker',
-	'tog-variantconversion',
+	'tog-nolangconversion',
 	'tog-noconvertlink',
 	'yourvariant',
 	'variantname-zh-hans',
diff --git a/maintenance/language/messages.inc b/maintenance/language/messages.inc
index 61f160dcc265..96107c052695 100644
--- a/maintenance/language/messages.inc
+++ b/maintenance/language/messages.inc
@@ -53,7 +53,7 @@ $wgMessageStructure = array(
 		'tog-watchlisthideliu',
 		'tog-watchlisthideanons',
 		'tog-watchlisthidepatrolled',
-		'tog-variantconversion',
+		'tog-nolangconversion',
 		'tog-ccmeonemails',
 		'tog-diffonly',
 		'tog-showhiddencats',
diff --git a/skins/Vector.php b/skins/Vector.php
index a98e4abbd8a1..42fdb39b7ed6 100644
--- a/skins/Vector.php
+++ b/skins/Vector.php
@@ -48,7 +48,7 @@ class SkinVector extends SkinTemplate {
 	 */
 	function buildNavigationUrls() {
 		global $wgContLang, $wgLang, $wgOut, $wgUser, $wgRequest;
-		global $wgEnableVariants;
+		global $wgDisableLangConversion;
 
 		wfProfileIn( __METHOD__ );
 
@@ -291,7 +291,7 @@ class SkinVector extends SkinTemplate {
 		// Gets list of language variants
 		$variants = $wgContLang->getVariants();
 		// Checks that language conversion is enabled and variants exist
-		if( $wgEnableVariants && count( $variants ) > 1 ) {
+		if( !$wgDisableLangConversion && count( $variants ) > 1 ) {
 			// Gets preferred variant
 			$preferred = $wgContLang->getPreferredVariant();
 			// Loops over each variant