test: Add tests for wallet mempool conflicts

Author: ishaanam

test/functional/wallet_conflicts.py

@@ -9,6 +9,7 @@
 
 from decimal import Decimal
 
+from test_framework.blocktools import COINBASE_MATURITY
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
         assert_equal,
@@ -28,6 +29,20 @@ def get_utxo_of_value(self, from_tx_id, search_value):
         return next(tx_out["vout"] for tx_out in self.nodes[0].gettransaction(from_tx_id)["details"] if tx_out["amount"] == Decimal(f"{search_value}"))
 
     def run_test(self):
+        """
+        The following tests check the behavior of the wallet when
+        transaction conflicts are created. These conflicts are created
+        using raw transaction RPCs that double-spend UTXOs and have more
+        fees, replacing the original transaction.
+        """
+
+        self.test_block_conflicts()
+        self.generatetoaddress(self.nodes[0], COINBASE_MATURITY + 7, self.nodes[2].getnewaddress())
+        self.test_mempool_conflict()
+        self.test_mempool_and_block_conflicts()
+        self.test_descendants_with_mempool_conflicts()
+
+    def test_block_conflicts(self):
         self.log.info("Send tx from which to conflict outputs later")
         txid_conflict_from_1 = self.nodes[0].sendtoaddress(self.nodes[0].getnewaddress(), Decimal("10"))
         txid_conflict_from_2 = self.nodes[0].sendtoaddress(self.nodes[0].getnewaddress(), Decimal("10"))
@@ -123,5 +138,272 @@ def run_test(self):
         assert_equal(former_conflicted["confirmations"], 1)
         assert_equal(former_conflicted["blockheight"], 217)
 
+    def test_mempool_conflict(self):
+        self.nodes[0].createwallet("alice")
+        alice = self.nodes[0].get_wallet_rpc("alice")
+
+        bob = self.nodes[1]
+
+        self.nodes[2].send(outputs=[{alice.getnewaddress() : 25} for _ in range(3)])
+        self.generate(self.nodes[2], 1)
+
+        self.log.info("Test a scenario where a transaction has a mempool conflict")
+
+        unspents = alice.listunspent()
+        assert_equal(len(unspents), 3)
+        assert all([tx["amount"] == 25 for tx in unspents])
+
+        # tx1 spends unspent[0] and unspent[1]
+        raw_tx = alice.createrawtransaction(inputs=[unspents[0], unspents[1]], outputs=[{bob.getnewaddress() : 49.9999}])
+        tx1 = alice.signrawtransactionwithwallet(raw_tx)['hex']
+
+        # tx2 spends unspent[1] and unspent[2], conflicts with tx1
+        raw_tx = alice.createrawtransaction(inputs=[unspents[1], unspents[2]], outputs=[{bob.getnewaddress() : 49.99}])
+        tx2 = alice.signrawtransactionwithwallet(raw_tx)['hex']
+
+        # tx3 spends unspent[2], conflicts with tx2
+        raw_tx = alice.createrawtransaction(inputs=[unspents[2]], outputs=[{bob.getnewaddress() : 24.9899}])
+        tx3 = alice.signrawtransactionwithwallet(raw_tx)['hex']
+
+        # broadcast tx1
+        tx1_txid = alice.sendrawtransaction(tx1)
+
+        assert_equal(alice.listunspent(), [unspents[2]])
+        assert_equal(alice.getbalance(), 25)
+
+        # broadcast tx2, replaces tx1 in mempool
+        tx2_txid = alice.sendrawtransaction(tx2)
+
+        # Check that unspent[0] is still not available because the wallet does not know that the tx spending it has a mempool conflicted
+        assert_equal(alice.listunspent(), [])
+        assert_equal(alice.getbalance(), 0)
+
+        self.log.info("Test scenario where a mempool conflict is removed")
+
+        # broadcast tx3, replaces tx2 in mempool
+        # Now that tx1's conflict has been removed, tx1 is now
+        # not conflicted, and instead is inactive until it is
+        # rebroadcasted. Now unspent[0] is not available, because
+        # tx1 is no longer conflicted.
+        alice.sendrawtransaction(tx3)
+
+        assert tx1_txid not in self.nodes[0].getrawmempool()
+
+        # now all of alice's outputs should be considered spent
+        # unspent[0]: spent by inactive tx1
+        # unspent[1]: spent by inactive tx1
+        # unspent[2]: spent by active tx3
+        assert_equal(alice.listunspent(), [])
+        assert_equal(alice.getbalance(), 0)
+
+        # Clean up for next test
+        bob.sendall([self.nodes[2].getnewaddress()])
+        self.generate(self.nodes[2], 1)
+
+        alice.unloadwallet()
+
+    def test_mempool_and_block_conflicts(self):
+        self.nodes[0].createwallet("alice_2")
+        alice = self.nodes[0].get_wallet_rpc("alice_2")
+        bob = self.nodes[1]
+
+        self.nodes[2].send(outputs=[{alice.getnewaddress() : 25} for _ in range(3)])
+        self.generate(self.nodes[2], 1)
+
+        self.log.info("Test a scenario where a transaction has both a block conflict and a mempool conflict")
+        unspents = [{"txid" : element["txid"], "vout" : element["vout"]} for element in alice.listunspent()]
+
+        assert_equal(bob.getbalances()["mine"]["untrusted_pending"], 0)
+
+        # alice and bob nodes are disconnected so that transactions can be
+        # created by alice, but broadcasted from bob so that alice's wallet
+        # doesn't know about them
+        self.disconnect_nodes(0, 1)
+
+        # Sends funds to bob
+        raw_tx = alice.createrawtransaction(inputs=[unspents[0]], outputs=[{bob.getnewaddress() : 24.99999}])
+        raw_tx1 = alice.signrawtransactionwithwallet(raw_tx)['hex']
+        tx1_txid = bob.sendrawtransaction(raw_tx1) # broadcast original tx spending unspents[0] only to bob
+
+        # create a conflict to previous tx (also spends unspents[0]), but don't broadcast, sends funds back to alice
+        raw_tx = alice.createrawtransaction(inputs=[unspents[0], unspents[2]], outputs=[{alice.getnewaddress() : 49.999}])
+        tx1_conflict = alice.signrawtransactionwithwallet(raw_tx)['hex']
+
+        # Sends funds to bob
+        raw_tx = alice.createrawtransaction(inputs=[unspents[1]], outputs=[{bob.getnewaddress() : 24.9999}])
+        raw_tx2 = alice.signrawtransactionwithwallet(raw_tx)['hex']
+        tx2_txid = bob.sendrawtransaction(raw_tx2) # broadcast another original tx spending unspents[1] only to bob
+
+        # create a conflict to previous tx (also spends unspents[1]), but don't broadcast, sends funds to alice
+        raw_tx = alice.createrawtransaction(inputs=[unspents[1]], outputs=[{alice.getnewaddress() : 24.9999}])
+        tx2_conflict = alice.signrawtransactionwithwallet(raw_tx)['hex']
+
+        bob_unspents = [{"txid" : element, "vout" : 0} for element in [tx1_txid, tx2_txid]]
+
+        # tx1 and tx2 are now in bob's mempool, and they are unconflicted, so bob has these funds
+        assert_equal(bob.getbalances()["mine"]["untrusted_pending"], Decimal("49.99989000"))
+
+        # spend both of bob's unspents, child tx of tx1 and tx2
+        raw_tx = bob.createrawtransaction(inputs=[bob_unspents[0], bob_unspents[1]], outputs=[{bob.getnewaddress() : 49.999}])
+        raw_tx3 = bob.signrawtransactionwithwallet(raw_tx)['hex']
+        tx3_txid = bob.sendrawtransaction(raw_tx3) # broadcast tx only to bob
+
+        # alice knows about 0 txs, bob knows about 3
+        assert_equal(len(alice.getrawmempool()), 0)
+        assert_equal(len(bob.getrawmempool()), 3)
+
+        assert_equal(bob.getbalances()["mine"]["untrusted_pending"], Decimal("49.99900000"))
+
+        # bob broadcasts tx_1 conflict
+        tx1_conflict_txid = bob.sendrawtransaction(tx1_conflict)
+        assert_equal(len(alice.getrawmempool()), 0)
+        assert_equal(len(bob.getrawmempool()), 2) # tx1_conflict kicks out both tx1, and its child tx3
+
+        assert tx2_txid in bob.getrawmempool()
+        assert tx1_conflict_txid in bob.getrawmempool()
+
+        # check that the tx2 unspent is still not available because the wallet does not know that the tx spending it has a mempool conflict
+        assert_equal(bob.getbalances()["mine"]["untrusted_pending"], 0)
+
+        # we will be disconnecting this block in the future
+        alice.sendrawtransaction(tx2_conflict)
+        assert_equal(len(alice.getrawmempool()), 1) # currently alice's mempool is only aware of tx2_conflict
+        # 11 blocks are mined so that when they are invalidated, tx_2
+        # does not get put back into the mempool
+        blk = self.generate(self.nodes[0], 11, sync_fun=self.no_op)[0]
+        assert_equal(len(alice.getrawmempool()), 0) # tx2_conflict is now mined
+
+        self.connect_nodes(0, 1)
+        self.sync_blocks()
+        assert_equal(alice.getbestblockhash(), bob.getbestblockhash())
+
+        # now that tx2 has a block conflict, tx1_conflict should be the only tx in bob's mempool
+        assert tx1_conflict_txid in bob.getrawmempool()
+        assert_equal(len(bob.getrawmempool()), 1)
+
+        # tx3 should now also be block-conflicted by tx2_conflict
+        assert_equal(bob.gettransaction(tx3_txid)["confirmations"], -11)
+        # bob has no pending funds, since tx1, tx2, and tx3 are all conflicted
+        assert_equal(bob.getbalances()["mine"]["untrusted_pending"], 0)
+        bob.invalidateblock(blk) # remove tx2_conflict
+        # bob should still have no pending funds because tx1 and tx3 are still conflicted, and tx2 has not been re-broadcast
+        assert_equal(bob.getbalances()["mine"]["untrusted_pending"], 0)
+        assert_equal(len(bob.getrawmempool()), 1)
+        # check that tx3 is no longer block-conflicted
+        assert_equal(bob.gettransaction(tx3_txid)["confirmations"], 0)
+
+        bob.sendrawtransaction(raw_tx2)
+        assert_equal(bob.getbalances()["mine"]["untrusted_pending"], 0)
+
+        # create a conflict to previous tx (also spends unspents[2]), but don't broadcast, sends funds back to alice
+        raw_tx = alice.createrawtransaction(inputs=[unspents[2]], outputs=[{alice.getnewaddress() : 24.99}])
+        tx1_conflict_conflict = alice.signrawtransactionwithwallet(raw_tx)['hex']
+
+        bob.sendrawtransaction(tx1_conflict_conflict) # kick tx1_conflict out of the mempool
+        bob.sendrawtransaction(raw_tx1) #re-broadcast tx1 because it is no longer conflicted
+
+        # Now bob has no pending funds because tx1 and tx2 are spent by tx3, which hasn't been re-broadcast yet
+        assert_equal(bob.getbalances()["mine"]["untrusted_pending"], 0)
+
+        bob.sendrawtransaction(raw_tx3)
+        assert_equal(len(bob.getrawmempool()), 4) # The mempool contains: tx1, tx2, tx1_conflict_conflict, tx3
+        assert_equal(bob.getbalances()["mine"]["untrusted_pending"], Decimal("49.99900000"))
+
+        # Clean up for next test
+        bob.reconsiderblock(blk)
+        assert_equal(alice.getbestblockhash(), bob.getbestblockhash())
+        self.sync_mempools()
+        self.generate(self.nodes[2], 1)
+
+        alice.unloadwallet()
+
+    def test_descendants_with_mempool_conflicts(self):
+        self.nodes[0].createwallet("alice_3")
+        alice = self.nodes[0].get_wallet_rpc("alice_3")
+
+        self.nodes[2].send(outputs=[{alice.getnewaddress() : 25} for _ in range(2)])
+        self.generate(self.nodes[2], 1)
+
+        self.nodes[1].createwallet("bob_1")
+        bob = self.nodes[1].get_wallet_rpc("bob_1")
+
+        self.nodes[2].createwallet("carol")
+        carol = self.nodes[2].get_wallet_rpc("carol")
+
+        self.log.info("Test a scenario where a transaction's parent has a mempool conflict")
+
+        unspents = alice.listunspent()
+        assert_equal(len(unspents), 2)
+        assert all([tx["amount"] == 25 for tx in unspents])
+
+        assert_equal(alice.getrawmempool(), [])
+
+        # Alice spends first utxo to bob in tx1
+        raw_tx = alice.createrawtransaction(inputs=[unspents[0]], outputs=[{bob.getnewaddress() : 24.9999}])
+        tx1 = alice.signrawtransactionwithwallet(raw_tx)['hex']
+        tx1_txid = alice.sendrawtransaction(tx1)
+
+        self.sync_mempools()
+
+        assert_equal(alice.getbalance(), 25)
+        assert_equal(bob.getbalances()["mine"]["untrusted_pending"], Decimal("24.99990000"))
+
+        raw_tx = bob.createrawtransaction(inputs=[bob.listunspent(minconf=0)[0]], outputs=[{carol.getnewaddress() : 24.999}])
+        # Bob creates a child to tx1
+        tx1_child = bob.signrawtransactionwithwallet(raw_tx)['hex']
+        tx1_child_txid = bob.sendrawtransaction(tx1_child)
+
+        self.sync_mempools()
+
+        # Currently neither tx1 nor tx1_child should have any conflicts
+        assert tx1_txid in bob.getrawmempool()
+        assert tx1_child_txid in bob.getrawmempool()
+        assert_equal(len(bob.getrawmempool()), 2)
+
+        assert_equal(bob.getbalances()["mine"]["untrusted_pending"], 0)
+        assert_equal(carol.getbalances()["mine"]["untrusted_pending"], Decimal("24.99900000"))
+
+        # Alice spends first unspent again, conflicting with tx1
+        raw_tx = alice.createrawtransaction(inputs=[unspents[0], unspents[1]], outputs=[{carol.getnewaddress() : 49.99}])
+        tx1_conflict = alice.signrawtransactionwithwallet(raw_tx)['hex']
+        tx1_conflict_txid = alice.sendrawtransaction(tx1_conflict)
+
+        self.sync_mempools()
+
+        assert_equal(bob.getbalances()["mine"]["untrusted_pending"], 0)
+        assert_equal(carol.getbalances()["mine"]["untrusted_pending"], Decimal("49.99000000"))
+
+        assert tx1_txid not in bob.getrawmempool()
+        assert tx1_child_txid not in bob.getrawmempool()
+        assert tx1_conflict_txid in bob.getrawmempool()
+        assert_equal(len(bob.getrawmempool()), 1)
+
+        # Now create a conflict to tx1_conflict, so that it gets kicked out of the mempool
+        raw_tx = alice.createrawtransaction(inputs=[unspents[1]], outputs=[{carol.getnewaddress() : 24.9895}])
+        tx1_conflict_conflict = alice.signrawtransactionwithwallet(raw_tx)['hex']
+        tx1_conflict_conflict_txid = alice.sendrawtransaction(tx1_conflict_conflict)
+
+        self.sync_mempools()
+
+        # Both tx1 and tx1_child are still not in the mempool because they have not be re-broadcasted
+        assert tx1_txid not in bob.getrawmempool()
+        assert tx1_child_txid not in bob.getrawmempool()
+        assert tx1_conflict_txid not in bob.getrawmempool()
+        assert tx1_conflict_conflict_txid in bob.getrawmempool()
+        assert_equal(len(bob.getrawmempool()), 1)
+
+        assert_equal(alice.getbalance(), 0)
+        assert_equal(bob.getbalances()["mine"]["untrusted_pending"], 0)
+        assert_equal(carol.getbalances()["mine"]["untrusted_pending"], Decimal("24.98950000"))
+
+        # Both tx1 and tx1_child can now be re-broadcasted
+        bob.sendrawtransaction(tx1)
+        bob.sendrawtransaction(tx1_child)
+        assert_equal(len(bob.getrawmempool()), 3)
+
+        alice.unloadwallet()
+        bob.unloadwallet()
+        carol.unloadwallet()
+
 if __name__ == '__main__':
     TxConflicts().main()