1  #!/usr/bin/env python3
  2  # Copyright (c) 2021 The Bitcoin Core developers
  3  # Distributed under the MIT software license, see the accompanying
  4  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  5  """
  6  Test mempool acceptance in case of an already known transaction
  7  with identical non-witness data but different witness.
  8  """
  9  
 10  from copy import deepcopy
 11  from test_framework.messages import (
 12      COIN,
 13      COutPoint,
 14      CTransaction,
 15      CTxIn,
 16      CTxInWitness,
 17      CTxOut,
 18      sha256,
 19  )
 20  from test_framework.p2p import P2PTxInvStore
 21  from test_framework.script import (
 22      CScript,
 23      OP_0,
 24      OP_ELSE,
 25      OP_ENDIF,
 26      OP_EQUAL,
 27      OP_HASH160,
 28      OP_IF,
 29      OP_TRUE,
 30      hash160,
 31  )
 32  from test_framework.test_framework import BitcoinTestFramework
 33  from test_framework.util import (
 34      assert_equal,
 35  )
 36  
 37  class MempoolWtxidTest(BitcoinTestFramework):
 38      def set_test_params(self):
 39          self.num_nodes = 1
 40          self.setup_clean_chain = True
 41  
 42      def run_test(self):
 43          node = self.nodes[0]
 44  
 45          self.log.info('Start with empty mempool and 101 blocks')
 46          # The last 100 coinbase transactions are premature
 47          blockhash = self.generate(node, 101)[0]
 48          txid = node.getblock(blockhash=blockhash, verbosity=2)["tx"][0]["txid"]
 49          assert_equal(node.getmempoolinfo()['size'], 0)
 50  
 51          self.log.info("Submit parent with multiple script branches to mempool")
 52          hashlock = hash160(b'Preimage')
 53          witness_script = CScript([OP_IF, OP_HASH160, hashlock, OP_EQUAL, OP_ELSE, OP_TRUE, OP_ENDIF])
 54          witness_program = sha256(witness_script)
 55          script_pubkey = CScript([OP_0, witness_program])
 56  
 57          parent = CTransaction()
 58          parent.vin.append(CTxIn(COutPoint(int(txid, 16), 0), b""))
 59          parent.vout.append(CTxOut(int(9.99998 * COIN), script_pubkey))
 60          parent.rehash()
 61  
 62          privkeys = [node.get_deterministic_priv_key().key]
 63          raw_parent = node.signrawtransactionwithkey(hexstring=parent.serialize().hex(), privkeys=privkeys)['hex']
 64          parent_txid = node.sendrawtransaction(hexstring=raw_parent, maxfeerate=0)
 65          self.generate(node, 1)
 66  
 67          peer_wtxid_relay = node.add_p2p_connection(P2PTxInvStore())
 68  
 69          # Create a new transaction with witness solving first branch
 70          child_witness_script = CScript([OP_TRUE])
 71          child_witness_program = sha256(child_witness_script)
 72          child_script_pubkey = CScript([OP_0, child_witness_program])
 73  
 74          child_one = CTransaction()
 75          child_one.vin.append(CTxIn(COutPoint(int(parent_txid, 16), 0), b""))
 76          child_one.vout.append(CTxOut(int(9.99996 * COIN), child_script_pubkey))
 77          child_one.wit.vtxinwit.append(CTxInWitness())
 78          child_one.wit.vtxinwit[0].scriptWitness.stack = [b'Preimage', b'\x01', witness_script]
 79          child_one_wtxid = child_one.getwtxid()
 80          child_one_txid = child_one.rehash()
 81  
 82          # Create another identical transaction with witness solving second branch
 83          child_two = deepcopy(child_one)
 84          child_two.wit.vtxinwit[0].scriptWitness.stack = [b'', witness_script]
 85          child_two_wtxid = child_two.getwtxid()
 86          child_two_txid = child_two.rehash()
 87  
 88          assert_equal(child_one_txid, child_two_txid)
 89          assert child_one_wtxid != child_two_wtxid
 90  
 91          self.log.info("Submit child_one to the mempool")
 92          txid_submitted = node.sendrawtransaction(child_one.serialize().hex())
 93          assert_equal(node.getmempoolentry(txid_submitted)['wtxid'], child_one_wtxid)
 94  
 95          peer_wtxid_relay.wait_for_broadcast([child_one_wtxid])
 96          assert_equal(node.getmempoolinfo()["unbroadcastcount"], 0)
 97  
 98          # testmempoolaccept reports the "already in mempool" error
 99          assert_equal(node.testmempoolaccept([child_one.serialize().hex()]), [{
100              "txid": child_one_txid,
101              "wtxid": child_one_wtxid,
102              "allowed": False,
103              "reject-reason": "txn-already-in-mempool"
104          }])
105          assert_equal(node.testmempoolaccept([child_two.serialize().hex()])[0], {
106              "txid": child_two_txid,
107              "wtxid": child_two_wtxid,
108              "allowed": False,
109              "reject-reason": "txn-same-nonwitness-data-in-mempool"
110          })
111  
112          # sendrawtransaction will not throw but quits early when the exact same transaction is already in mempool
113          node.sendrawtransaction(child_one.serialize().hex())
114  
115          self.log.info("Connect another peer that hasn't seen child_one before")
116          peer_wtxid_relay_2 = node.add_p2p_connection(P2PTxInvStore())
117  
118          self.log.info("Submit child_two to the mempool")
119          # sendrawtransaction will not throw but quits early when a transaction with the same non-witness data is already in mempool
120          node.sendrawtransaction(child_two.serialize().hex())
121  
122          # The node should rebroadcast the transaction using the wtxid of the correct transaction
123          # (child_one, which is in its mempool).
124          peer_wtxid_relay_2.wait_for_broadcast([child_one_wtxid])
125          assert_equal(node.getmempoolinfo()["unbroadcastcount"], 0)
126  
127  if __name__ == '__main__':
128      MempoolWtxidTest().main()