Inside Bitcoin

1#!/usr/bin/env python3
2# Copyright (c) 2024-present 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"""Helpful routines for mempool testing."""
6import random
7
8from .blocktools import (
9    COINBASE_MATURITY,
10)
11from .messages import (
12    COutPoint,
13    CTransaction,
14    CTxIn,
15    CTxInWitness,
16    CTxOut,
17)
18from .script import (
19    CScript,
20    OP_RETURN,
21)
22from .util import (
23    assert_equal,
24    assert_greater_than,
25    create_lots_of_big_transactions,
26    gen_return_txouts,
27)
28from .wallet import (
29    MiniWallet,
30)
31
32# Default for -minrelaytxfee in sat/kvB
33DEFAULT_MIN_RELAY_TX_FEE = 100
34# Default for -incrementalrelayfee in sat/kvB
35DEFAULT_INCREMENTAL_RELAY_FEE = 100
36DEFAULT_CLUSTER_LIMIT = 64
37DEFAULT_CLUSTER_SIZE_LIMIT_KVB = 101
38
39TRUC_MAX_VSIZE = 10000
40TRUC_CHILD_MAX_VSIZE = 1000
41
42def assert_mempool_contents(test_framework, node, expected=None, sync=True):
43    """Assert that all transactions in expected are in the mempool,
44    and no additional ones exist. 'expected' is an array of
45    CTransaction objects
46    """
47    if sync:
48        test_framework.sync_mempools()
49    if not expected:
50        expected = []
51    assert_equal(len(expected), len(set(expected)))
52    mempool = node.getrawmempool(verbose=False)
53    assert_equal(len(mempool), len(expected))
54    for tx in expected:
55        assert tx.txid_hex in mempool
56
57
58def fill_mempool(test_framework, node, *, tx_sync_fun=None):
59    """Fill mempool until eviction.
60
61    Allows for simpler testing of scenarios with floating mempoolminfee > minrelay
62    Requires -maxmempool=5.
63    To avoid unintentional tx dependencies, the mempool filling txs are created with a
64    tagged ephemeral miniwallet instance.
65    """
66    test_framework.log.info("Fill the mempool until eviction is triggered and the mempoolminfee rises")
67    txouts = gen_return_txouts()
68    minrelayfee = node.getnetworkinfo()['relayfee']
69
70    tx_batch_size = 1
71    num_of_batches = 75
72    # Generate UTXOs to flood the mempool
73    # 1 to create a tx initially that will be evicted from the mempool later
74    # 75 transactions each with a fee rate higher than the previous one
75    ephemeral_miniwallet = MiniWallet(node, tag_name="fill_mempool_ephemeral_wallet")
76    test_framework.generate(ephemeral_miniwallet, 1 + num_of_batches * tx_batch_size)
77
78    # Mine enough blocks so that the UTXOs are allowed to be spent
79    test_framework.generate(node, COINBASE_MATURITY - 1)
80
81    # Get all UTXOs up front to ensure none of the transactions spend from each other, as that may
82    # change their effective feerate and thus the order in which they are selected for eviction.
83    confirmed_utxos = [ephemeral_miniwallet.get_utxo(confirmed_only=True) for _ in range(num_of_batches * tx_batch_size + 1)]
84    assert_equal(len(confirmed_utxos), num_of_batches * tx_batch_size + 1)
85
86    test_framework.log.debug("Create a mempool tx that will be evicted")
87    tx_to_be_evicted_id = ephemeral_miniwallet.send_self_transfer(
88        from_node=node, utxo_to_spend=confirmed_utxos.pop(0), fee_rate=minrelayfee)["txid"]
89
90    def send_batch(fee):
91        utxos = confirmed_utxos[:tx_batch_size]
92        create_lots_of_big_transactions(ephemeral_miniwallet, node, fee, tx_batch_size, txouts, utxos)
93        del confirmed_utxos[:tx_batch_size]
94
95    # Increase the tx fee rate to give the subsequent transactions a higher priority in the mempool
96    # The tx has an approx. vsize of 65k, i.e. multiplying the previous fee rate (in sats/kvB)
97    # by 130 should result in a fee that corresponds to 2x of that fee rate
98    base_fee = minrelayfee * 130
99    batch_fees = [(i + 1) * base_fee for i in range(num_of_batches)]
100
101    test_framework.log.debug("Fill up the mempool with txs with higher fee rate")
102    for fee in batch_fees[:-3]:
103        send_batch(fee)
104    tx_sync_fun() if tx_sync_fun else test_framework.sync_mempools()  # sync before any eviction
105    assert_equal(node.getmempoolinfo()["mempoolminfee"], minrelayfee)
106    for fee in batch_fees[-3:]:
107        send_batch(fee)
108    tx_sync_fun() if tx_sync_fun else test_framework.sync_mempools()  # sync after all evictions
109
110    test_framework.log.debug("The tx should be evicted by now")
111    # The number of transactions created should be greater than the ones present in the mempool
112    assert_greater_than(tx_batch_size * num_of_batches, len(node.getrawmempool()))
113    # Initial tx created should not be present in the mempool anymore as it had a lower fee rate
114    assert tx_to_be_evicted_id not in node.getrawmempool()
115
116    test_framework.log.debug("Check that mempoolminfee is larger than minrelaytxfee")
117    assert_equal(node.getmempoolinfo()['minrelaytxfee'], minrelayfee)
118    assert_greater_than(node.getmempoolinfo()['mempoolminfee'], minrelayfee)
119
120def tx_in_orphanage(node, tx: CTransaction) -> bool:
121    """Returns true if the transaction is in the orphanage."""
122    found = [o for o in node.getorphantxs(verbosity=1) if o["txid"] == tx.txid_hex and o["wtxid"] == tx.wtxid_hex]
123    return len(found) == 1
124
125def create_large_orphan():
126    """Create huge orphan transaction"""
127    tx = CTransaction()
128    # Nonexistent UTXO
129    tx.vin = [CTxIn(COutPoint(random.randrange(1 << 256), random.randrange(1, 100)))]
130    tx.wit.vtxinwit = [CTxInWitness()]
131    tx.wit.vtxinwit[0].scriptWitness.stack = [CScript(b'X' * 390000)]
132    tx.vout = [CTxOut(100, CScript([OP_RETURN, b'a' * 20]))]
133    return tx
134