Exclude spent outputs from remote staking balance (#1000)

At the moment, WalletExtension::GetRemoteStakingBalance counts every output in remote staking coinbase and shows incorrect data in getwalletinfo response.
This change excludes spent outputs from remote staking balance.

* Ignore spent transaction in WalletExtension::GetRemoteStakingBalance
* Don't count spent outputs in GetRemoteStakingBalance
* Fix nits
* Check actual balance unchanged
* Add a test case for remote stake spending

Signed-off-by: Dmitry Saveliev <dima@thirdhash.com>

src/esperanza/walletextension.cpp

@@ -121,11 +121,16 @@ CAmount WalletExtension::GetRemoteStakingBalance() const {
   CAmount balance = 0;
 
   for (const auto &it : m_enclosing_wallet.mapWallet) {
-    const CWalletTx *const tx = &it.second;
+    const CWalletTx &tx = it.second;
+    const uint256 &tx_hash = tx.GetHash();
 
-    for (const auto &txout : tx->tx->vout) {
-      if (::IsStakedRemotely(m_enclosing_wallet, txout.scriptPubKey)) {
-        balance += txout.nValue;
+    for (size_t i = 0; i < tx.tx->vout.size(); ++i) {
+      const CTxOut &tx_out = tx.tx->vout[i];
+      if (m_enclosing_wallet.IsSpent(tx_hash, i)) {
+        continue;
+      }
+      if (::IsStakedRemotely(m_enclosing_wallet, tx_out.scriptPubKey)) {
+        balance += tx_out.nValue;
       }
     }
   }

test/functional/feature_remote_staking.py

@@ -2,11 +2,36 @@
 # Copyright (c) 2019 The Unit-e Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
-from test_framework.mininode import sha256
+from test_framework.blocktools import (
+    create_block,
+    create_coinbase,
+    get_tip_snapshot_meta,
+    sign_coinbase,
+)
+from test_framework.mininode import (
+    msg_witness_block,
+    network_thread_start,
+    P2PInterface,
+    sha256,
+)
 from test_framework.regtest_mnemonics import regtest_mnemonics
-from test_framework.script import CScript, OP_2, hash160
-from test_framework.test_framework import UnitETestFramework, STAKE_SPLIT_THRESHOLD
-from test_framework.util import assert_equal, assert_greater_than, bytes_to_hex_str, hex_str_to_bytes, wait_until
+from test_framework.script import (
+    CScript,
+    OP_2,
+    hash160,
+)
+from test_framework.test_framework import (
+    UnitETestFramework,
+    PROPOSER_REWARD,
+    STAKE_SPLIT_THRESHOLD,
+)
+from test_framework.util import (
+    assert_equal,
+    assert_greater_than,
+    bytes_to_hex_str,
+    hex_str_to_bytes,
+    wait_until,
+)
 
 
 def stake_p2wsh(node, staking_node, amount):
@@ -18,23 +43,49 @@ def stake_p2wsh(node, staking_node, amount):
         staking_node: the node which will be able to stake nodes
         amount: the amount to send
     """
-    multisig = node.addmultisigaddress(2, [node.getnewaddress(), node.getnewaddress()])
+    multisig = node.addmultisigaddress(
+        2, [node.getnewaddress(), node.getnewaddress()])
     bare = CScript(hex_str_to_bytes(multisig['redeemScript']))
     spending_script_hash = sha256(bare)
 
-    addr_info = staking_node.validateaddress(staking_node.getnewaddress('', 'legacy'))
+    addr_info = staking_node.validateaddress(
+        staking_node.getnewaddress('', 'legacy'))
     staking_key_hash = hash160(hex_str_to_bytes(addr_info['pubkey']))
 
     rs_p2wsh = CScript([OP_2, staking_key_hash, spending_script_hash])
-    outputs = [{'address': 'script', 'amount': amount, 'script': bytes_to_hex_str(rs_p2wsh)}]
-    node.sendtypeto('unite', 'unite', outputs)
+    outputs = [{'address': 'script', 'amount': amount,
+                'script': bytes_to_hex_str(rs_p2wsh)}]
+    return node.sendtypeto('unite', 'unite', outputs)
+
+
+def build_block_with_remote_stake(node):
+    height = node.getblockcount()
+    snapshot_meta = get_tip_snapshot_meta(node)
+    stakes = node.liststakeablecoins()
+
+    coin = stakes['stakeable_coins'][0]['coin']
+    script_pubkey = hex_str_to_bytes(coin['script_pub_key']['hex'])
+    stake = {
+        'txid': coin['out_point']['txid'],
+        'vout': coin['out_point']['n'],
+        'amount': coin['amount'],
+    }
+
+    tip = int(node.getbestblockhash(), 16)
+    block_time = node.getblock(
+        node.getbestblockhash())['time'] + 1
+    coinbase = sign_coinbase(
+        node, create_coinbase(
+            height, stake, snapshot_meta.hash, raw_script_pubkey=script_pubkey))
+
+    return create_block(tip, coinbase, block_time)
 
 
 class RemoteStakingTest(UnitETestFramework):
     def set_test_params(self):
         self.num_nodes = 2
         self.setup_clean_chain = True
-        self.extra_args=[
+        self.extra_args = [
             [],
             ['-minimumchainwork=0', '-maxtipage=1000000000']
         ]
@@ -43,8 +94,13 @@ def run_test(self):
         alice, bob = self.nodes
         alice.importmasterkey(regtest_mnemonics[0]['mnemonics'])
 
+        bob.add_p2p_connection(P2PInterface())
+        network_thread_start()
+        bob.p2p.wait_for_verack()
+
         alice.generate(1)
-        assert_equal(len(alice.listunspent()), regtest_mnemonics[0]['balance'] / STAKE_SPLIT_THRESHOLD)
+        assert_equal(len(alice.listunspent()),
+                     regtest_mnemonics[0]['balance'] / STAKE_SPLIT_THRESHOLD)
 
         alices_addr = alice.getnewaddress()
 
@@ -60,21 +116,50 @@ def run_test(self):
         assert_equal(ps['wallets'][0]['stakeable_balance'], 0)
 
         # Stake the funds
-        result = alice.stakeat(recipient)
-        stake_p2wsh(alice, staking_node=bob, amount=1)
+        tx1_hash = alice.stakeat(recipient)
+        tx2_hash = stake_p2wsh(alice, staking_node=bob, amount=1)
         alice.generatetoaddress(1, alices_addr)
         self.sync_all()
 
+        # Estimate Alice balance
+        tx1_fee = alice.gettransaction(tx1_hash)['fee']
+        tx2_fee = alice.gettransaction(tx2_hash)['fee']
+        alice_balance = regtest_mnemonics[0]['balance'] + tx1_fee + tx2_fee
+
         wi = alice.getwalletinfo()
         assert_equal(wi['remote_staking_balance'], 2)
+        assert_equal(wi['balance'], alice_balance)
 
         def bob_is_staking_the_new_coin():
             ps = bob.proposerstatus()
             return ps['wallets'][0]['stakeable_balance'] == 2
         wait_until(bob_is_staking_the_new_coin, timeout=10)
 
+        # Bob generates a new block with remote stake of Alice
+        block = build_block_with_remote_stake(bob)
+        bob.p2p.send_and_ping(msg_witness_block(block))
+        self.sync_all()
+
+        # Reward from the Bob's block comes to remote staking balance of Alice
+        # Actual spendable balance shouldn't change because the reward is not yet mature
+        wi = alice.getwalletinfo()
+        assert_equal(wi['remote_staking_balance'], 2 + PROPOSER_REWARD)
+        assert_equal(wi['balance'], alice_balance)
+
         # Change outputs for both staked coins, and the balance staked remotely
-        assert_equal(len(alice.listunspent()), 2 + (regtest_mnemonics[0]['balance'] // STAKE_SPLIT_THRESHOLD))
+        assert_equal(len(alice.listunspent()), 2 +
+                     (regtest_mnemonics[0]['balance'] // STAKE_SPLIT_THRESHOLD))
+
+        # Chech that Alice can spend remotely staked coins
+        inputs = []
+        for coin in bob.liststakeablecoins()['stakeable_coins']:
+            out_point = coin['coin']['out_point']
+            inputs.append({'tx': out_point['txid'], 'n': out_point['n']})
+        alice.sendtypeto('', '', [{'address': alices_addr, 'amount': 1.9}], '', '', False,
+                         {'changeaddress': alices_addr, 'inputs': inputs})
+
+        wi = alice.getwalletinfo()
+        assert_equal(wi['remote_staking_balance'], PROPOSER_REWARD)
 
 
 if __name__ == '__main__':

test/functional/test_framework/blocktools.py

@@ -69,7 +69,7 @@ def serialize_script_num(value):
 # If pubkey is passed in, the coinbase outputs will be P2PK outputs;
 # otherwise anyone-can-spend outputs. The first output is the reward,
 # which is not spendable for COINBASE_MATURITY blocks.
-def create_coinbase(height, stake, snapshot_hash, pubkey = None, n_pieces = 1):
+def create_coinbase(height, stake, snapshot_hash, pubkey=None, raw_script_pubkey=None, n_pieces=1):
     assert n_pieces > 0
     stake_in = COutPoint(int(stake['txid'], 16), stake['vout'])
     coinbase = CTransaction()
@@ -81,6 +81,8 @@ def create_coinbase(height, stake, snapshot_hash, pubkey = None, n_pieces = 1):
     output_script = None
     if (pubkey != None):
         output_script = CScript([pubkey, OP_CHECKSIG])
+    elif raw_script_pubkey is not None:
+        output_script = CScript(raw_script_pubkey)
     else:
         output_script = CScript([OP_TRUE])