When a git rev-list is run that excludes a non-existent ref the caret (^) character is included in the git output

$ git rev-list --all master ^foo
fatal: bad revision '^foo'

The caret prefix is then included in the
NoSuchCommitException#getCommitId which violated the contract for this method. The contract for NoSuchCommitException#getCommitId id defined as

Retrieves the ID for which no matching commit was found. If a path was supplied when 
attempting retrieve the commit, this is the ID of the starting commit