refs: read FETCH_HEAD and MERGE_HEAD generically

[git] / mergetools / opendiff

diff_cmd () {
        "$merge_tool_path" "$LOCAL" "$REMOTE" | cat
}

merge_cmd () {
        if $base_present
        then
                "$merge_tool_path" "$LOCAL" "$REMOTE" \
                        -ancestor "$BASE" -merge "$MERGED" | cat
        else
                "$merge_tool_path" "$LOCAL" "$REMOTE" \
                        -merge "$MERGED" | cat
        fi
}