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Fatal error due to passing invalid title to Linker::link (from a summary)
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Author: wiki.bugzilla

Please go to and click the two 'last' diff links in the middle of the list (the two revisions by user Asset, 2008-07-14). Both only give fatal internal errors atm.

Linker::link passed invalid target

#0 /usr/local/apache/common-local/php-1.5/includes/Linker.php(1227): Linker->link(NULL, '???', Array, Array, 'noclasses')
#1 [internal function]: Linker->formatAutocommentsCallback(Array)
#2 /usr/local/apache/common-local/php-1.5/includes/Linker.php(1194): preg_replace_callback('!(.*)/\*\s*(.*?...', Array, '/* Homepage sho...')
#3 /usr/local/apache/common-local/php-1.5/includes/Linker.php(1167): Linker->formatAutocomments('/* Homepage sho...', Object(Title), true)
#4 /usr/local/apache/common-local/php-1.5/includes/Linker.php(1316): Linker->formatComment('/* Homepage sho...', Object(Title), true)
#5 /usr/local/apache/common-local/php-1.5/includes/Linker.php(1334): Linker->commentBlock('/* Homepage sho...', Object(Title), true)
#6 /usr/local/apache/common-local/php-1.5/includes/diff/DifferenceEngine.php(266): Linker->revComment(Object(Revision), true, true)
#7 /usr/local/apache/common-local/php-1.5/includes/Article.php(738): DifferenceEngine->showDiffPage(false)
#8 /usr/local/apache/common-local/php-1.5/includes/Wiki.php(436): Article->view()
#9 /usr/local/apache/common-local/php-1.5/includes/Wiki.php(59): MediaWiki->performAction(Object(OutputPage), Object(Article), Object(Title), Object(User), Object(WebRequest))
#10 /usr/local/apache/common-local/php-1.5/index.php(93): MediaWiki->initialize(Object(Title), Object(Article), Object(OutputPage), Object(User), Object(WebRequest))
#11 /usr/local/apache/common-local/live-1.5/index.php(3): require('/usr/local/apac...')
#12 {main}

Quoting from #wikimedia-tech:
"<Raymond_afk> seems like the linker does not like a comment "Homepage shows up with just �‹�""

Note that these characters are only present in the comment for one of the two diffs. The newer one's summary is simply "Email problems".

Version: 1.14.x
Severity: major



Event Timeline

bzimport raised the priority of this task from to Medium.Nov 21 2014, 10:18 PM
bzimport set Reference to bz15351.
bzimport added a subscriber: Unknown Object (MLST).

ayg wrote:

I can't reproduce. The issue is that the character UTF8_REPLACEMENT is not supposed to be valid in titles. When you pass the text to Title::newFromText(), it will get rejected. Is U+FFFD supposed to be valid in article text? In fragments?

It should be worked around in r40194, but this is a workaround, not a proper fix, so I'm not closing the bug.

Fixed in r40305. Reproduced in r40041 and solution tested. $section is user input and Title::newFromText() has every right to reject it. Titles are restricted in the kind of text they can contain. Any caller passing user input to Title::newFromText() must check for failure.

Not present in 1.13 because makeKnownLinkObj() failed gracefully in that version.