A standard Tuleap installation comes with two installations of git:
- /usr/bin
- /opt/rh/sclo-git212/root/usr/bin/

The Git_Exec class adapt path to the Git command in order to use the most specific one.

The revListSinceStart function pipes two git commands but only one is adapted.

A possible fix:

$this->gitCmdWithOutput('rev-parse --not ' . $other_branches . ' | ' . this->getGitCommand() . ' rev-list --stdin ' . escapeshellarg($newrev), $output);