Storage Decoding error when querying system.account.at() from a historic block

[TarikGul]

Resproducible Example:

const { ApiPromise, WsProvider } = require('@polkadot/api');

const main = async () => {
    const api = await ApiPromise.create({
        provider: new WsProvider('wss://kusama-rpc.polkadot.io'),
    });
    
    const ALICE = '5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY';
    
    // Block Height 467568
    const historicBlockHash = '0x3361f6446c72aaa6679aa40a03e493a851161fd08cb53237968a9967902691c0'
    const { data: { free } } = await api.query.system.account.at(historicBlockHash, ALICE);

    console.log('Alice has a free balance of ', free.toHuman());
}

Resulting error:

RPC-CORE: getStorage(key: StorageKey, at?: BlockHash): StorageData:: Unable to decode storage system.account:: createType(AccountInfo):: {"nonce":"Index","refcount":"RefCount","data":"AccountData"}:: Decoded input doesn't match input, received 0x0000000000000000000000000000000000000000000000000000000000000000…0000000000000000000000000000000000000000000000000000000000000000 (80 bytes), created 0x0000000000000000000000000000000000000000000000000000000000000000…0000000000000000000000000000000000000000000000000000000000000000 (69 bytes)
Error: Unable to decode storage system.account:: createType(AccountInfo):: {"nonce":"Index","refcount":"RefCount","data":"AccountData"}:: Decoded input doesn't match input, received 0x0000000000000000000000000000000000000000000000000000000000000000…0000000000000000000000000000000000000000000000000000000000000000 (80 bytes), created 0x0000000000000000000000000000000000000000000000000000000000000000…0000000000000000000000000000000000000000000000000000000000000000 (69 bytes)
    at RpcCore._newType (/Users/tarik/Desktop/parity/sanity-checks/polka-test/node_modules/@polkadot/rpc-core/bundle.cjs:450:13)
    at RpcCore._formatStorageData (/Users/tarik/Desktop/parity/sanity-checks/polka-test/node_modules/@polkadot/rpc-core/bundle.cjs:399:17)
    at RpcCore._formatOutput (/Users/tarik/Desktop/parity/sanity-checks/polka-test/node_modules/@polkadot/rpc-core/bundle.cjs:376:19)
    at callWithRegistry (/Users/tarik/Desktop/parity/sanity-checks/polka-test/node_modules/@polkadot/rpc-core/bundle.cjs:255:42)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)

Using @polkadot/api 5.4.1

Rel: #634

Per the related issue:

this breakage may have something to do with a change of the storage key location for balances or account info.

[jacogr]

There is pre introduction of system.account - so whatever it returns won't be decodable.

// get API instance with metadata at a specific hash
const a = await api.at('0x3361f6446c72aaa6679aa40a03e493a851161fd08cb53237968a9967902691c0');

// [accountNonce, extrinsicCount, allExtrinsicsWeight, allExtrinsicsLen, blockHash, extrinsicData, number, parentHash, extrinsicsRoot, digest, events, eventCount, eventTopics]
console.log(Object.keys(a.query.system));

Rather at this point of the chain evolution it is a balances.freeBalance query` -

const ALICE = '5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY';

const a = await api.at('0x3361f6446c72aaa6679aa40a03e493a851161fd08cb53237968a9967902691c0');

// [totalIssuance, vesting, freeBalance, reservedBalance, locks]
console.log(Object.keys(a.query.balances));
console.log((await a.query.balances.freeBalance(ALICE)).toHuman())

// for extra benefit, the nonce (at this point stored in system)
console.log((await a.query.system.accountNonce(ALICE)).toHuman())

[TarikGul]

Thanks for the response on this! Will close due to this giving enough context to find a work around for our problem!

Thanks again.

[polkadot-js-bot]

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