For a "YAML" lockfile, you could probably write a much simpler and much more performant parser that throws out much of what makes YAML complicated, in particular, anchors, data type tags, all the ways of doing multi-line strings, all the weird unexpected type conversions (like yes/no converting to a boolean)... If the lockfile is never meant to be edited by human hands, only reviewed by human eyes, you can build a much simpler parser for something like:
