#!/bin/sh

. git-sh-setup-script || die "Not a git archive"

if [ -n "$(git-diff-files)" ]; then
    echo The following files should be updated!
    echo
    git-diff-files | awk '{print $6}'
fi

undostack=$GIT_DIR/undostack

headtree=$(git-cat-file commit $(cat $GIT_DIR/HEAD) | head -n 1 | sed -e 's/tree //')
undotree=$(git-write-tree)

if [ $headtree == $undotree ]; then
    echo There are no changes to undo.
else
    {
       echo $headtree
       echo $undotree
    } >> $undostack

    echo Saved current state as tree $undotree.
    echo Reverting to HEAD, $headtree...

    git-checkout-script -f
fi