Balance discrepancy in stagenet network

[Demontager]

While running monerod-lws-daemon development against monero master in stagenet i have noticed that monero-lws rest server responds with a wrong account balance, but when i call monero-wallet-rpc it replies with correct one.

Getting balance with monero-lws while fully synced to pruned stagenet:

starting monero-lws-daemon
monero-lws-daemon --daemon tcp://127.0.0.1:18082 --db-path /home/dem/.lws --rest-server http://127.0.0.1:8443 --log-level=2 --network=stage --admin-rest-server http://127.0.0.1:8444 --auto-accept-creation

request
$ curl --location --request POST 'http://127.0.0.1:8443/get_address_info' --header 'Content-Type: application/json' --data-raw '{"address":"56QfWzKA55rePZLXySYNPoRM5pMDsUCZN2KtEGqBe7NNfeRoRQ3NY1iTsYhZkymWqWUyUNa1s2H2i2vNsYFKau7SMdV8XE8","view_key":"2383530d2a71d0d6b464f5154968f7afa1f828cfbd42a7f9ee09ba9d2fb1d004"}'
{"locked_funds":"0","total_received":"19899926890000","total_sent":"19899926890000","scanned_height":1702197,"scanned_block_height":1702197,"start_height":1000000,"transaction_height":1702197,"blockchain_height":1702197,"spent_outputs":[{"amount":"10000000000000","key_image":"c461e166100134a8c14c4d2380fdb9f8c04d4caf962a39c84f996e6b8be35a36","tx_pub_key":"6a93b36c054a4fe9edc3d6694e7f7764552c0fe8933a6ef30db0a5544446b538","out_index":0,"mixin":15,"sender":{"maj_i":0,"min_i":0}},{"amount":"9899926890000","key_image":"f3c6fb96718b2f8f214b9c0af69d946f094f1c71b80ba13a42163dc62b3b66b0","tx_pub_key":"ee53ee0a1ab90ac3d99ad5b5764dd07c3f403c21d436f5b27eef3dae2bd4ee7f","out_index":1,"mixin":15,"sender":{"maj_i":0,"min_i":0}}]}(venv)

Now counting wallet balance total_received: 19899926890000 - total_sent: 19899926890000 = 0

And getting actual correct balance by calling wallet rpc server

starting wallet rpc server
$ monero-wallet-rpc --stagenet --rpc-bind-port 38083 --rpc-bind-ip 127.0.0.1 --wallet-file /home/dem/Monero/wallet2 --password SecretPassword --trusted-daemon --disable-rpc-login --non-interactive

request
$ curl -s -X POST http://127.0.0.1:38083/json_rpc -d '{"jsonrpc":"2.0","id":"0","method":"get_balance"}' -H 'Content-Type: application/json' | jq '.result | {balance: (.balance / 1e12), unlocked_balance: (.unlocked_balance / 1e12)}'
{
  "balance": 9.89992689,
  "unlocked_balance": 9.89992689
}

[vtnerd]

LWS doesn't have the spend private key, so it cannot compute the correct balance. The spend key is needed to determine the "real" spends, and filter out the times an output was used in someone else's ring signature. This should change with "carrot" (the next version of Monero addresses), where LWS could have a balance-view-key but still not have the spend key.

The total_received and total_sent aren't particularly useful (IMO), but an original part of the spec. The total_received includes change, and total_sent includes "dummy" spends, so the numbers can't really be used directly.

It does look like LWS is missing a receive, so perhaps a rescan from an earlier height is needed?

[Demontager]

It does look like LWS is missing a receive, so perhaps a rescan from an earlier height is needed?

Rescanning from earlier hight doesn't change figures. I thought mymonero using some sort of modified LWS as you wrote earlier and therefore provides actual balance. Is it possible to provide LWS with private spend key instead to calculate correct balance?

[vtnerd]

I thought mymonero using some sort of modified LWS as you wrote earlier and therefore provides actual balance. Is it possible to provide LWS with private spend key instead to calculate correct balance?

Not currently. The closest is the unfinished lwfs project.

Perhaps a custom REST endpoint (for just for the balance) or a small custom frontend for the same. Thoughts?

[Demontager]

Perhaps a custom REST endpoint (for just for the balance) or a small custom frontend for the same. Thoughts?

I'd personally prefer REST endpoint rather than dedicated project, because it has very close origin to what lws has now.