z40=0000000000000000000000000000000000000000
while read local_ref local_sha remote_ref remote_sha
do
    if [ "$local_sha" != $z40 ]; then
        if [ "$remote_sha" = $z40 ]; then
            # First ancestor not found in remote
            first_ancestor=$(git rev-list --topo-order --reverse "$local_sha" --not --remotes="$1" | head -n 1)
            if [ -n "$first_ancestor" ]; then
                # Check that the ancestor has at least one parent
                git rev-list --max-parents=0 "$local_sha" | grep "$first_ancestor" > /dev/null
                if [ $? -ne 0 ]; then
                    args="run --all-files"
                else
                    source=$(git rev-parse "$first_ancestor"^)
                    args="run --origin $local_sha --source $source"
                fi
            fi
        else
            args="run --origin $local_sha --source $remote_sha"
        fi
    fi
done

if [ "$args" != "" ]; then
    args="$args --hook-stage push"
else
    # If args is empty, then an attempt to push on an empty
    # changeset is being made. In this case, just exit cleanly
    exit 0
fi