Migrate from JavaScript number to string in JSON RPC API when representing u64 values

[steveluscher]

Note: this will require a massive multi-year migration plan; this issue is just a stub now to point some TODOs to.

Problem

Responses from our JSON RPC API represent u64 numbers as JavaScript numbers. Since JavaScript numbers are IEEE 754 floating point, this will result in truncation above 2^53 (ie. 9007199254740992).

Example: If you call getAccountInfo on an account with more than 9,007,199.254740992◎, the lamports field will be truncated. You can convince yourself of this by executing the following statement in a JS repl:

JSON.parse('{"lamports":9007199254740993}');
> 9007199254740992

Proposed Solution

Return u64 as a value object through the JSON RPC API.

A value object is one with some content and a tag that denotes its type.

{
  "jsonrpc":"2.0",
  "result": {
    "commitment":[
      { "_": 0, "v": "0" },
      { "_": 0, "v": "0" },
      { "_": 0, "v": "0" },
      /* ... */
      { "_": 0, "v": "382219010785520358" },
    ],
    "totalStake": { "_": 0, "v": "383784289656803160" },
  },
  "id":1,
}

Where _ is an enum denoting the type of the value (eg. here 0 would be mapped to bigint) then the rest of the object is the data (eg. here v is the bigint value as a string).

Using value objects makes it so that the client doesn't have to keep a giant map of keypaths that are supposed to actually be strings vs. are strings but need to be cast to bigint. All it needs to do is to look for the tag (_) and deserialize the value accordingly.

Deprecation Plan

There are many ways to do a deprecation like this. This GitHub issue is only a stub for now; we will discuss how to move forward in the coming months.

[mschneider]

massive multi-year migration plan

If solana can break jsonrpc compatibility in minor versions once a year, an important issue like this one, shouldn't be held back.

[steveluscher]

Working on it ser. One step at a time.

https://github.com/solana-labs/solana-web3.js/blob/b69daf278045bc96740450e123a322e0dd95f60e/packages/rpc-core/src/response-patcher.ts#L35-L38

[buffalojoec]

Just noting this strategy should apply to f64 as well