wikimedia / mediawiki

			// Step 0: Prepare and validate the input

			$user = User::newFromName( $state['username'], 'creatable' );

			if ( !is_object( $user ) ) {

				$session->remove( 'AuthManager::accountCreationState' );

				$this->logger->debug( __METHOD__ . ': Invalid username', [

					'user' => $state['username'],

				] );

				return AuthenticationResponse::newFail( wfMessage( 'noname' ) );

			}

			if ( $state['creatorid'] ) {

				$creator = User::newFromId( $state['creatorid'] );

			// Avoid account creation races on double submissions

			$cache = \ObjectCache::getLocalClusterInstance();

			$lock = $cache->getScopedLock( $cache->makeGlobalKey( 'account', md5( $user->getName() ) ) );

			if ( !$lock ) {

				// Don't clear AuthManager::accountCreationState for this code

				// path because the process that won the race owns it.

				$this->logger->debug( __METHOD__ . ': Could not acquire account creation lock', [

					'user' => $user->getName(),

					'creator' => $creator->getName(),

				] );

				return AuthenticationResponse::newFail( wfMessage( 'usernameinprogress' ) );

			}

			// Permissions check

			$status = $this->checkAccountCreatePermissions( $creator );