Last modified: 2012-04-16 09:15:38 UTC
The query https://en.wikipedia.org/w/api.php?action=query&list=watchlist&wlprop=loginfo&wllimit=max shows the following output for me: <?xml version="1.0"?> <api servedby="srv265"> <error code="internal_api_error_MWException" info="Exception Caught: Internal error in ApiResult::setIndexedTagName: Bad parameter" xml:space="preserve"> #0 /usr/local/apache/common-local/php-1.19/includes/api/ApiBase.php(1300): wfDebugDieBacktrace('Internal error ...') #1 /usr/local/apache/common-local/php-1.19/includes/api/ApiResult.php(197): ApiBase::dieDebug('ApiResult::setI...', 'Bad parameter') #2 /usr/local/apache/common-local/php-1.19/includes/api/ApiQueryLogEvents.php(264): ApiResult->setIndexedTagName('???[edit=autoco...', 'param') #3 /usr/local/apache/common-local/php-1.19/includes/api/ApiQueryWatchlist.php(306): ApiQueryLogEvents::addLogParams(Object(ApiResult), Array, '???[edit=autoco...', 'protect', 'protect', '20120403012329') #4 /usr/local/apache/common-local/php-1.19/includes/api/ApiQueryWatchlist.php(201): ApiQueryWatchlist->extractRowInfo(Object(stdClass)) #5 /usr/local/apache/common-local/php-1.19/includes/api/ApiQueryWatchlist.php(40): ApiQueryWatchlist->run() #6 /usr/local/apache/common-local/php-1.19/includes/api/ApiQuery.php(266): ApiQueryWatchlist->execute() #7 /usr/local/apache/common-local/php-1.19/includes/api/ApiMain.php(705): ApiQuery->execute() #8 /usr/local/apache/common-local/php-1.19/includes/api/ApiMain.php(360): ApiMain->executeAction() #9 /usr/local/apache/common-local/php-1.19/includes/api/ApiMain.php(344): ApiMain->executeActionWithErrorHandling() #10 /usr/local/apache/common-local/php-1.19/api.php(117): ApiMain->execute() #11 /usr/local/apache/common-local/live-1.5/api.php(3): require('/usr/local/apac...') #12 {main} </error> </api> It seems to happen when a watchlist entry refers to a protection, but not when it's an edit or a move. I can replicate the error on my local wiki (although without the stack trace) that runs from master. And showing the same protection using list=recentchanges works fine.
Adding Niklas since, IIRC, he worked on the logging changes.
Can't reproduce on local installation (git master) or mediawiki.org (1.20wmf1). It seems the issue has been fixed.
(In reply to comment #2) You're right, this bug is a duplicate of #35723, which has been fixed. *** This bug has been marked as a duplicate of bug 35723 ***