Internal error

From SMC Wiki

[9471bc6949dc5c99ad2fbb02] /index.php?title=%E0%B4%AA%E0%B5%8D%E0%B4%B0%E0%B4%A7%E0%B4%BE%E0%B4%A8_%E0%B4%A4%E0%B4%BE%E0%B4%B3%E0%B5%8D%E2%80%8D&diff=cur&oldid=1510 Error: Call to a member function getUser() on null

Backtrace:

from /var/www/wiki.smc.org.in/includes/diff/DifferenceEngine.php(1677)
#0 /var/www/wiki.smc.org.in/includes/diff/DifferenceEngine.php(1204): DifferenceEngine->getMultiNotice()
#1 /var/www/wiki.smc.org.in/includes/diff/DifferenceEngine.php(1159): DifferenceEngine->getDiff()
#2 /var/www/wiki.smc.org.in/includes/diff/DifferenceEngine.php(922): DifferenceEngine->showDiff()
#3 /var/www/wiki.smc.org.in/includes/page/Article.php(952): DifferenceEngine->showDiffPage()
#4 /var/www/wiki.smc.org.in/includes/page/Article.php(486): Article->showDiffPage()
#5 /var/www/wiki.smc.org.in/includes/actions/ViewAction.php(78): Article->view()
#6 /var/www/wiki.smc.org.in/includes/MediaWiki.php(556): ViewAction->show()
#7 /var/www/wiki.smc.org.in/includes/MediaWiki.php(333): MediaWiki->performAction()
#8 /var/www/wiki.smc.org.in/includes/MediaWiki.php(923): MediaWiki->performRequest()
#9 /var/www/wiki.smc.org.in/includes/MediaWiki.php(576): MediaWiki->main()
#10 /var/www/wiki.smc.org.in/index.php(50): MediaWiki->run()
#11 /var/www/wiki.smc.org.in/index.php(46): wfIndexMain()
#12 {main}