Travis builds fails on HHVM for the wikibase-api project. The error is related to composer installation:
composer --version Composer version 1.5.6 2017-12-18 12:09:18 before_script 24.01s$ travis_retry composer install Loading composer repositories with package information Updating dependencies (including require-dev) Package operations: 46 installs, 0 updates, 0 removals - Installing data-values/interfaces (0.2.5): Downloading (100%) ... Writing lock file Generating autoload files 11.63s$ cd tests/unit && ../../vendor/bin/phpunit --coverage-clover=coverage.clover && cd ../../ Generating autoload files Fatal error: Function already defined: composerRequirea5243776c84e7c8d7d3901633774cd22 in /home/travis/build/addwiki/wikibase-api/vendor/autoload.php on line 5