This is not verified in test or dev, only at a local repo.

Create [[Mediawiki:Vector.js]] and [[Mediawiki:Vector.css]] and make additional revisjons. Then take a diff between the two revisions. The following was then spit out from a localhost. It seems to be identical for both pages. The following is from the css page.

Notice: Undefined property: DifferenceEngine::$mContentObject in /home/john/Workspace/core/includes/diff/DifferenceEngine.php on line 525 Call Stack: 0.0004 648480

1. 1. {main}() /home/john/Workspace/core/index.php:0 0.0309 4170776
   2. MediaWiki->run() /home/john/Workspace/core/index.php:59 0.0310 4170776
   3. MediaWiki->main() /home/john/Workspace/core/includes/Wiki.php:446 0.0884 7562064
   4. MediaWiki->performRequest() /home/john/Workspace/core/includes/Wiki.php:536 0.0990 8477808
   5. MediaWiki->performAction() /home/john/Workspace/core/includes/Wiki.php:304 0.1040 8495416
   6. ViewAction->show() /home/john/Workspace/core/includes/Wiki.php:427 0.1040 8495416
   7. Article->view() /home/john/Workspace/core/includes/actions/ViewAction.php:37 0.1068 8509528
   8. Article->showDiffPage() /home/john/Workspace/core/includes/Article.php:553 0.1271 9460728
   9. DifferenceEngine->showDiffPage() /home/john/Workspace/core/includes/Article.php:823 0.5088 21291408
2. DifferenceEngine->renderNewRevision() /home/john/Workspace/core/includes/diff/DifferenceEngine.php:415

Fatal error: Call to a member function getParserOutput() on a non-object in /home/john/Workspace/core/includes/diff/DifferenceEngine.php on line 525 Call Stack: 0.0004 648480

1. 1. {main}() /home/john/Workspace/core/index.php:0 0.0309 4170776
   2. MediaWiki->run() /home/john/Workspace/core/index.php:59 0.0310 4170776
   3. MediaWiki->main() /home/john/Workspace/core/includes/Wiki.php:446 0.0884 7562064
   4. MediaWiki->performRequest() /home/john/Workspace/core/includes/Wiki.php:536 0.0990 8477808
   5. MediaWiki->performAction() /home/john/Workspace/core/includes/Wiki.php:304 0.1040 8495416
   6. ViewAction->show() /home/john/Workspace/core/includes/Wiki.php:427 0.1040 8495416
   7. Article->view() /home/john/Workspace/core/includes/actions/ViewAction.php:37 0.1068 8509528
   8. Article->showDiffPage() /home/john/Workspace/core/includes/Article.php:553 0.1271 9460728
   9. DifferenceEngine->showDiffPage() /home/john/Workspace/core/includes/Article.php:823 0.5088 21291408
2. DifferenceEngine->renderNewRevision() /home/john/Workspace/core/includes/diff/DifferenceEngine.php:415

Version: master
Severity: blocker