Breaks parser tests if you have the debug comments option enabled:
bawolff@Bawolff-L:/var/www/w/phase3$ php tests/parserTests.php Warning: array_map(): An error occurred while invoking the map callback in /var/www/w/phase3/includes/GlobalFunctions.php on line 338 Warning: array_map(): An error occurred while invoking the map callback in /var/www/w/phase3/includes/GlobalFunctions.php on line 338 Warning: array_map(): An error occurred while invoking the map callback in /var/www/w/phase3/includes/GlobalFunctions.php on line 338 Unstub loop detected on call of $wgOut->debug from array_map Backtrace: #0 /var/www/w/phase3/includes/StubObject.php(57): StubObject->_unstub('debug', 5) #1 /var/www/w/phase3/includes/StubObject.php(76): StubObject->_call('debug', Array) #2 [internal function]: StubObject->__call('debug', Array) #3 [internal function]: StubObject->debug('Unstubbing $wgL...') #4 /var/www/w/phase3/includes/GlobalFunctions.php(338): array_map(Array, Array) #5 /var/www/w/phase3/includes/StubObject.php(102): wfDebug('Unstubbing $wgO...') #6 /var/www/w/phase3/includes/StubObject.php(57): StubObject->_unstub('debug', 5) #7 /var/www/w/phase3/includes/StubObject.php(76): StubObject->_call('debug', Array) #8 [internal function]: StubObject->__call('debug', Array) #9 [internal function]: StubObject->debug('Unstubbing $wgL...') #10 /var/www/w/phase3/includes/GlobalFunctions.php(338): array_map(Array, Array) #11 /var/www/w/phase3/includes/StubObject.php(102): wfDebug('Unstubbing $wgO...') #12 /var/www/w/phase3/includes/StubObject.php(57): StubObject->_unstub('debug', 5) #13 /var/www/w/phase3/includes/StubObject.php(76): StubObject->_call('debug', Array) #14 [internal function]: StubObject->__call('debug', Array) #15 [internal function]: StubObject->debug('Unstubbing $wgL...') #16 /var/www/w/phase3/includes/GlobalFunctions.php(338): array_map(Array, Array) #17 /var/www/w/phase3/includes/StubObject.php(102): wfDebug('Unstubbing $wgL...') #18 /var/www/w/phase3/includes/StubObject.php(57): StubObject->_unstub('getCode', 5) #19 /var/www/w/phase3/includes/StubObject.php(147): StubObject->_call('getCode', Array) #20 /var/www/w/phase3/includes/cache/MessageCache.php(595): StubUserLang->__call('getCode', Array) #21 /var/www/w/phase3/includes/cache/MessageCache.php(595): StubUserLang->getCode() #22 /var/www/w/phase3/includes/GlobalFunctions.php(835): MessageCache->get('version-svn-rev...', true, false) #23 /var/www/w/phase3/includes/GlobalFunctions.php(799): wfMsgGetKey('version-svn-rev...', true, false, true) #24 /var/www/w/phase3/includes/GlobalFunctions.php(685): wfMsgReal('version-svn-rev...', Array, true) #25 /var/www/w/phase3/includes/specials/SpecialVersion.php(176): wfMsg('version-svn-rev...', 88648, 88648) #26 /var/www/w/phase3/tests/parserTests.php(84): SpecialVersion::getVersion() #27 {main}