API account counter issue

[lrettig]

Description

Calling GlobalStateService.Account returns the actual account counter (nonce) (along with balance) from global state. However, this is not the counter value that should be included in a newly-submitted tx. For a new tx, the system expects the counter to match the projected counter value returned by TransactionProcessor.GetProjection, which factors in pending transactions:

go-spacemesh/mesh/meshdb.go

Lines 576 to 584 in 1c81878

	// GetProjection returns projection of address
	func (m *DB) GetProjection(addr types.Address, prevNonce, prevBalance uint64) (nonce, balance uint64, err error) {
	pending, err := m.getAccountPendingTxs(addr)
	if err != nil {
	return 0, 0, err
	}
	nonce, balance = pending.GetProjection(prevNonce, prevBalance)
	return nonce, balance, nil
	}

If a client naively reads account data from the API, then tries to submit a tx, it will fail as a result.

CC @noamnelke @avive, would appreciate your input on this.

Steps To Reproduce

1. Call GlobalStateService.Account
2. Submit a new, valid tx to TransactionService.SubmitTransaction using the account counter you just got. If there are any pending txs from this sender, it will fail.

Expected Behavior

I see a few options:

• return projected counter and balance instead of current values from global state - probably a bad idea
• add a new API endpoint to get projected account data
• add projected data to the existing account API endpoints

[noamnelke]

The old api had GetNonce and GetBalace endpoints which returned projected values.

I agree that it can be confusing to get an account info without the projected values. I think that from an api-consumer perspective it's best to get those values as part of the existing account endpoints, in addition to the "final" data from the state. Any reason not to do it that way?

[lrettig]

I agree. I'll update the API to add projected as well as current state values.

[lrettig]

The API has been updated. I'm adding support for the latest API release in #2133 which should take care of this.