Steps to reproduce:
1. Modify [[MediaWiki:Sidebar]] to
*1
**test-url|test
* navigation
** mainpage|mainpage-description
......
2. Save [[MediaWiki:Sidebar]]
Unexpected non-MediaWiki exception encountered, of type "InvalidArgumentException"
[96b109f7] /core/index.php/MediaWiki:Sidebar InvalidArgumentException from line 240 of ...\includes\Message.php: $key must be a string or an array
Backtrace:
#0 D:\F_Programmierung\xampp1.8.3\htdocs\core\includes\GlobalFunctions.php(1371): Message->__construct(integer, array)
#1 D:\F_Programmierung\xampp1.8.3\htdocs\core\skins\Vector\VectorTemplate.php(309): wfMessage(integer)
#2 D:\F_Programmierung\xampp1.8.3\htdocs\core\skins\Vector\VectorTemplate.php(293): VectorTemplate->renderPortal(integer, array)
#3 D:\F_Programmierung\xampp1.8.3\htdocs\core\skins\Vector\VectorTemplate.php(196): VectorTemplate->renderPortals(array)
#4 D:\F_Programmierung\xampp1.8.3\htdocs\core\includes\skins\SkinTemplate.php(243): VectorTemplate->execute()
#5 D:\F_Programmierung\xampp1.8.3\htdocs\core\includes\OutputPage.php(2266): SkinTemplate->outputPage()
#6 D:\F_Programmierung\xampp1.8.3\htdocs\core\includes\MediaWiki.php(594): OutputPage->output()
#7 D:\F_Programmierung\xampp1.8.3\htdocs\core\includes\MediaWiki.php(435): MediaWiki->main()
#8 D:\F_Programmierung\xampp1.8.3\htdocs\core\index.php(46): MediaWiki->run()
#9 {main}