It's not that uncommon to have de/serialization functions where g(f(x)) == x for all x, but f(g(x)) != x for some x. Usually people just need to be able to corr

It's not that uncommon to have de/serialization functions where g(f(x)) == x for all x, but f(g(x)) != x for some x. Usually people just need to be able to correctly deserialize any valid serialized string, and preferably detect when a serialized string is invalid. Being able to deserialize some arbitrary string that doesn't represent any valid value but which can somehow still be reserialized into the same arbitrary string is a rather unusual requirement.