I have been facing this issue since ui upgraded my magento site form 2.0.7 to 2.1.5. When trying to run magento setup:upgarde command to install extension it gives uncaught error class magento/indexer/model/config/reader in abstractFactory.php
Php version i am currently using is 7.0.17 . I have tried using di:compile also but of no use.
If some one can give a solution it will be of great help.