PublicKeys.toString does not produce the same format expected by PublicKeys.fromString

[FilipHarald]

This is not a bug, it's just a bit unintuitive that below code produce an error. I only tested this on 0.66.0.

import {PublicKeys} from "@aztec/aztec.js";
const pk = PublicKeys.random();
const pk2 = PublicKeys.fromString(pk.toString());

Error:

file:///home/filip/c/tonatiu/node_modules/@aztec/foundation/dest/serialize/buffer_reader.js:298
        throw new Error(`Attempted to read beyond buffer length. Start index: ${this.index}, Num bytes to read: ${numBytes}, Buffer length: ${this.buffer.length}`);
              ^

Error: Attempted to read beyond buffer length. Start index: 0, Num bytes to read: 32, Buffer length: 0
    at BufferReader._BufferReader_rangeCheck (file:///home/filip/c/tonatiu/node_modules/@aztec/foundation/dest/serialize/buffer_reader.js:298:15)
    at BufferReader.readBytes (file:///home/filip/c/tonatiu/node_modules/@aztec/foundation/dest/serialize/buffer_reader.js:127:94)
    at fromBuffer (file:///home/filip/c/tonatiu/node_modules/@aztec/foundation/dest/fields/fields.js:118:25)
    at Fr.fromBuffer (file:///home/filip/c/tonatiu/node_modules/@aztec/foundation/dest/fields/fields.js:171:16)
    at Point.fromBuffer (file:///home/filip/c/tonatiu/node_modules/@aztec/foundation/dest/fields/point.js:68:28)
    at BufferReader.readObject (file:///home/filip/c/tonatiu/node_modules/@aztec/foundation/dest/serialize/buffer_reader.js:226:29)
    at PublicKeys.fromBuffer (file:///home/filip/c/tonatiu/node_modules/@aztec/circuits.js/dest/types/public_keys.js:95:49)
    at PublicKeys.fromString (file:///home/filip/c/tonatiu/node_modules/@aztec/circuits.js/dest/types/public_keys.js:139:27)
    at file:///home/filip/c/tonatiu/services/aztec-scraper/build/src/index.js:7:24

Node.js v18.18.2

[FilipHarald]

The reason it's not working is that fromString does not expect a value prepended with "0x". So the following code will work:

import {PublicKeys} from "@aztec/aztec.js";
const pk = PublicKeys.random();
const pk2 = PublicKeys.fromString(pk.toString().slice(2));