Reproduction: browse to https://test.wikipedia.org/w/index.php?title=Special%3ALog&user=Jeff+G.

[Wh36ugpAEKsAAEXPgW8AAACX] /w/index.php?title=Special%3ALog&user=Jeff+G. BadMethodCallException from line 446 of /srv/mediawiki/php-1.31.0-wmf.10/includes/logging/LogPager.php: Call to a member function bitAnd() on a non-object (null)

Backtrace:

#0 /srv/mediawiki/php-1.31.0-wmf.10/includes/logging/LogPager.php(186): LogPager->enforcePerformerRestrictions()
#1 /srv/mediawiki/php-1.31.0-wmf.10/includes/logging/LogPager.php(79): LogPager->limitPerformer(string)
#2 /srv/mediawiki/php-1.31.0-wmf.10/includes/specials/SpecialLog.php(183): LogPager->__construct(LogEventsList, string, string, string, boolean, array, NULL, NULL, string, string)
#3 /srv/mediawiki/php-1.31.0-wmf.10/includes/specials/SpecialLog.php(109): SpecialLog->show(FormOptions, array)
#4 /srv/mediawiki/php-1.31.0-wmf.10/includes/specialpage/SpecialPage.php(522): SpecialLog->execute(NULL)
#5 /srv/mediawiki/php-1.31.0-wmf.10/includes/specialpage/SpecialPageFactory.php(578): SpecialPage->run(NULL)
#6 /srv/mediawiki/php-1.31.0-wmf.10/includes/MediaWiki.php(287): SpecialPageFactory::executePath(Title, RequestContext)
#7 /srv/mediawiki/php-1.31.0-wmf.10/includes/MediaWiki.php(851): MediaWiki->performRequest()
#8 /srv/mediawiki/php-1.31.0-wmf.10/includes/MediaWiki.php(523): MediaWiki->main()
#9 /srv/mediawiki/php-1.31.0-wmf.10/index.php(43): MediaWiki->run()
#10 /srv/mediawiki/w/index.php(3): include(string)
#11 {main}