2 calls to install_already_done_error()

install_begin_request in includes/install.core.inc: Begins an installation request, modifying the installation state as needed.
install_verify_completed_task in includes/install.core.inc: Verifies and returns the last installation task that was completed.

Buggy or inaccurate documentation? Please file an issue. Need support? Need help programming? Connect with the Drupal community.