To reproduce:
- edit any page at http://en.wikipedia.beta.wmflabs.org
- enter this at the top of the page: <math>3 + 2</math>
- click button Show preview
- error message appears:
Internal error
No backend defined with the name global-multiwrite.
Backtrace:
#0 /data/project/apache/common-local/php-master/extensions/Math/MathTexvc.php(229): FileBackendGroup->get('global-multiwri...')
#1 /data/project/apache/common-local/php-master/extensions/Math/MathTexvc.php(47): MathTexvc->getBackend()
#2 /data/project/apache/common-local/php-master/extensions/Math/MathTexvc.php(303): MathTexvc->getHashPath()
#3 /data/project/apache/common-local/php-master/extensions/Math/MathTexvc.php(32): MathTexvc->readCache()
#4 /data/project/apache/common-local/php-master/extensions/Math/Math.hooks.php(54): MathTexvc->render()
#5 [internal function]: MathHooks::mathTagHook('3 + 2', Array, Object(Parser), Object(PPFrame_DOM))
#6 /data/project/apache/common-local/php-master/includes/parser/Parser.php(3913): call_user_func_array(Array, Array)
#7 /data/project/apache/common-local/php-master/includes/parser/Preprocessor_DOM.php(1155): Parser->extensionSubstitution(Array, Object(PPFrame_DOM))
#8 /data/project/apache/common-local/php-master/includes/parser/Parser.php(3070): PPFrame_DOM->expand(Object(PPNode_DOM), 0)
#9 /data/project/apache/common-local/php-master/includes/parser/Parser.php(1148): Parser->replaceVariables('<math>3 + 2</ma...')
#10 /data/project/apache/common-local/php-master/includes/parser/Parser.php(383): Parser->internalParse('<math>3 + 2</ma...')
#11 /data/project/apache/common-local/php-master/includes/content/WikitextContent.php(300): Parser->parse('<math>3 + 2</ma...', Object(Title), Object(ParserOptions), true, true, NULL)
#12 /data/project/apache/common-local/php-master/includes/EditPage.php(3081): WikitextContent->getParserOutput(Object(Title), NULL, Object(ParserOptions))
#13 /data/project/apache/common-local/php-master/includes/EditPage.php(2103): EditPage->getPreviewText()
#14 /data/project/apache/common-local/php-master/includes/EditPage.php(441): EditPage->showEditForm()
#15 /data/project/apache/common-local/php-master/includes/actions/EditAction.php(50): EditPage->edit()
#16 /data/project/apache/common-local/php-master/includes/actions/EditAction.php(76): EditAction->show()
#17 /data/project/apache/common-local/php-master/includes/Wiki.php(439): SubmitAction->show()
#18 /data/project/apache/common-local/php-master/includes/Wiki.php(305): MediaWiki->performAction(Object(Article), Object(Title))
#19 /data/project/apache/common-local/php-master/includes/Wiki.php(565): MediaWiki->performRequest()
#20 /data/project/apache/common-local/php-master/includes/Wiki.php(458): MediaWiki->main()
#21 /data/project/apache/common-local/php-master/index.php(59): MediaWiki->run()
#22 /data/project/apache/common-local/w/index.php(3): require('/data/project/a...')
#23 {main}
Version: unspecified
Severity: major
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=45076