don't exit bash on /etc with uncommitted changes

As explained before by Zack, it might happen that you co-administer a machine and have /etc under some VCS (which you should anyway by using etckeeper).
There are a few problems like detecting the identity of the committer and don't leave /etc with uncommitted changes so I recently came up with a slighly different solution than the one we thought two years ago (besides switching from bzr to git).
Take committer name/email from ~/.gitconfig of the user owning the tty or GIT_CONFIG or GIT_CONFIG_LOCAL if they are set.
Trap a function on shell's EXIT rather than loop on .bash_logout which applies only to login shell.
The resulting code to be put in /root/.bashrc:

git_functions="/path/to/git-etc-common"



# export GIT_* variables

if [ -f "$git_functions" ]; then

  . "$git_functions"

  git_export_env

fi



case $- in

*i*)    # interactive shell

  check_uncommitted(){

    if [ -f "$git_functions" ]; then

      . "$git_functions"

      if ! git_etc_status; then

        echo "Uncommitted changes to /etc found, please commit them"

        bash -$-

      fi

    fi

  }

  trap check_uncommitted EXIT

;;

esac