I don't know which extension to blame for this one, so I'll tag all of them.
During user auto-creation, AbuseFilter calls `SpecialPage::getTitleFor`. During the hook for that method to allow extensions to add special pages, `TwoColConflictHooks::onSpecialPage_initList` calls `BetaFeatures::isFeatureEnabled` which attempts to load the user from session before it's ready.
One of the following must be true:
* `SpecialPage::getTitleFor` is not safe to call during auto-creation. Although that seems somewhat restrictive.
* `BetaFeatures::isFeatureEnabled` is not safe to call during auto-creation. Extensions should register their special pages without that conditional.
* `BetaFeatures::isFeatureEnabled` needs to somehow do its job without checking the session-user.
```
#0 /srv/mediawiki/php-1.31.0-wmf.2/includes/user/User.php(2233): User->load()
#1 /srv/mediawiki/php-1.31.0-wmf.2/includes/user/User.php(5277): User->getId()
#2 /srv/mediawiki/php-1.31.0-wmf.2/includes/user/User.php(2887): User->loadOptions()
#3 /srv/mediawiki/php-1.31.0-wmf.2/extensions/BetaFeatures/includes/BetaFeaturesUtil.php(43): User->getOption(string)
#4 /srv/mediawiki/php-1.31.0-wmf.2/extensions/TwoColConflict/includes/TwoColConflictHooks.php(124): BetaFeatures::isFeatureEnabled(User, string)
#5 /srv/mediawiki/php-1.31.0-wmf.2/includes/Hooks.php(177): TwoColConflictHooks::onSpecialPage_initList(array)
#6 /srv/mediawiki/php-1.31.0-wmf.2/includes/Hooks.php(205): Hooks::callHook(string, array, array, NULL)
#7 /srv/mediawiki/php-1.31.0-wmf.2/includes/specialpage/SpecialPageFactory.php(268): Hooks::run(string, array)
#8 /srv/mediawiki/php-1.31.0-wmf.2/includes/specialpage/SpecialPageFactory.php(285): SpecialPageFactory::getPageList()
#9 /srv/mediawiki/php-1.31.0-wmf.2/includes/specialpage/SpecialPageFactory.php(660): SpecialPageFactory::getAliasList()
#10 /srv/mediawiki/php-1.31.0-wmf.2/includes/specialpage/SpecialPage.php(98): SpecialPageFactory::getLocalNameFor(string, boolean)
#11 /srv/mediawiki/php-1.31.0-wmf.2/includes/specialpage/SpecialPage.php(85): SpecialPage::getTitleValueFor(string, boolean, string)
#12 /srv/mediawiki/php-1.31.0-wmf.2/extensions/AbuseFilter/includes/AbuseFilterPreAuthenticationProvider.php(41): SpecialPage::getTitleFor(string)
#13 /srv/mediawiki/php-1.31.0-wmf.2/extensions/AbuseFilter/includes/AbuseFilterPreAuthenticationProvider.php(13): AbuseFilterPreAuthenticationProvider->testUser(User, User, boolean)
#14 /srv/mediawiki/php-1.31.0-wmf.2/includes/auth/AuthManager.php(1649): AbuseFilterPreAuthenticationProvider->testUserForCreation(User, string, array)
#15 /srv/mediawiki/php-1.31.0-wmf.2/includes/Setup.php(869): MediaWiki\Auth\AuthManager->autoCreateUser(User, string, boolean)
#16 /srv/mediawiki/php-1.31.0-wmf.2/includes/WebStart.php(114): include(string)
#17 /srv/mediawiki/php-1.31.0-wmf.2/api.php(38): include(string)
#18 /srv/mediawiki/w/api.php(3): include(string)
#19 {main}
```
Alternative trace:
```
#0 /srv/mediawiki/php-1.31.0-wmf.2/includes/user/User.php(5269): User->load()
#1 /srv/mediawiki/php-1.31.0-wmf.2/includes/user/User.php(2887): User->loadOptions()
#2 /srv/mediawiki/php-1.31.0-wmf.2/extensions/BetaFeatures/includes/BetaFeaturesUtil.php(43): User->getOption(string)
#3 /srv/mediawiki/php-1.31.0-wmf.2/extensions/TwoColConflict/includes/TwoColConflictHooks.php(128): BetaFeatures::isFeatureEnabled(User, string)
#4 /srv/mediawiki/php-1.31.0-wmf.2/includes/Hooks.php(177): TwoColConflictHooks::onSpecialPage_initList(array)
#5 /srv/mediawiki/php-1.31.0-wmf.2/includes/Hooks.php(205): Hooks::callHook(string, array, array, NULL)
#6 /srv/mediawiki/php-1.31.0-wmf.2/includes/specialpage/SpecialPageFactory.php(268): Hooks::run(string, array)
#7 /srv/mediawiki/php-1.31.0-wmf.2/includes/specialpage/SpecialPageFactory.php(285): SpecialPageFactory::getPageList()
#8 /srv/mediawiki/php-1.31.0-wmf.2/includes/specialpage/SpecialPageFactory.php(660): SpecialPageFactory::getAliasList()
#9 /srv/mediawiki/php-1.31.0-wmf.2/includes/specialpage/SpecialPage.php(98): SpecialPageFactory::getLocalNameFor(string, string)
#10 /srv/mediawiki/php-1.31.0-wmf.2/includes/specialpage/SpecialPage.php(85): SpecialPage::getTitleValueFor(string, string, string)
#11 /srv/mediawiki/php-1.31.0-wmf.2/extensions/ShortUrl/ShortUrl.hooks.php(23): SpecialPage::getTitleFor(string, string)
#12 /srv/mediawiki/php-1.31.0-wmf.2/includes/Hooks.php(177): ShortUrlHooks::setupUrlRouting(PathRouter)
#13 /srv/mediawiki/php-1.31.0-wmf.2/includes/Hooks.php(205): Hooks::callHook(string, array, array, NULL)
#14 /srv/mediawiki/php-1.31.0-wmf.2/includes/WebRequest.php(171): Hooks::run(string, array)
#15 /srv/mediawiki/php-1.31.0-wmf.2/includes/WebRequest.php(316): WebRequest::getPathInfo(string)
#16 /srv/mediawiki/php-1.31.0-wmf.2/includes/Setup.php(721): WebRequest->interpolateTitle()
#17 /srv/mediawiki/php-1.31.0-wmf.2/includes/WebStart.php(114): include(string)
#18 /srv/mediawiki/php-1.31.0-wmf.2/index.php(40): include(string)
#19 /srv/mediawiki/w/index.php(3): include(string)
#20 {main}
```