From 8a6428a3f57ca9506b8366341a90d21bb7bf4716 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Bartosz=20Dziewo=C5=84ski?= <matma.rex@gmail.com>
Date: Sun, 27 Jul 2014 22:27:29 +0200
Subject: [PATCH] Preferences: Disable the 'skin' preference if there are no
 skins

Having a radio field with no valid values makes MediaWiki sad and
causes exceptions.

Also make double-sure that the global default value is not invalid.
That causes exceptions too.

Change-Id: I90cc9e6f40303aa5771c265948a0be4a4ce2e42c
---
 includes/Preferences.php | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/includes/Preferences.php b/includes/Preferences.php
index 084d6ab2e5..eb29e41508 100644
--- a/includes/Preferences.php
+++ b/includes/Preferences.php
@@ -579,12 +579,16 @@ class Preferences {
 		## Skin #####################################
 		global $wgAllowUserCss, $wgAllowUserJs;
 
-		$defaultPreferences['skin'] = array(
-			'type' => 'radio',
-			'options' => self::generateSkinOptions( $user, $context ),
-			'label' => '&#160;',
-			'section' => 'rendering/skin',
-		);
+		// Skin selector, if there is at least one valid skin
+		$skinOptions = self::generateSkinOptions( $user, $context );
+		if ( $skinOptions ) {
+			$defaultPreferences['skin'] = array(
+				'type' => 'radio',
+				'options' => $skinOptions,
+				'label' => '&#160;',
+				'section' => 'rendering/skin',
+			);
+		}
 
 		# Create links to user CSS/JS pages for all skins
 		# This code is basically copied from generateSkinOptions().  It'd
@@ -1064,12 +1068,14 @@ class Preferences {
 		}
 		asort( $validSkinNames );
 
+		$foundDefault = false;
 		foreach ( $validSkinNames as $skinkey => $sn ) {
 			$linkTools = array();
 
 			# Mark the default skin
 			if ( $skinkey == $wgDefaultSkin ) {
 				$linkTools[] = $context->msg( 'default' )->escaped();
+				$foundDefault = true;
 			}
 
 			# Create preview link
@@ -1094,6 +1100,12 @@ class Preferences {
 			$ret[$display] = $skinkey;
 		}
 
+		if ( !$foundDefault ) {
+			// If the default skin is not available, things are going to break horribly because the
+			// default value for skin selector will not be a valid value. Let's just not show it then.
+			return array();
+		}
+
 		return $ret;
 	}
 
-- 
2.20.1