aboutsummaryrefslogtreecommitdiff
path: root/test/functional/mempool_limit.py
blob: d46924f4ce683dfd3fda3d146490231d7519b355 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
#!/usr/bin/env python3
# Copyright (c) 2014-2022 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
"""Test mempool limiting together/eviction with the wallet."""

from decimal import Decimal

from test_framework.mempool_util import (
    fill_mempool,
)
from test_framework.p2p import P2PTxInvStore
from test_framework.test_framework import BitcoinTestFramework
from test_framework.util import (
    assert_equal,
    assert_fee_amount,
    assert_greater_than,
    assert_raises_rpc_error,
)
from test_framework.wallet import (
    COIN,
    DEFAULT_FEE,
    MiniWallet,
)


class MempoolLimitTest(BitcoinTestFramework):
    def set_test_params(self):
        self.setup_clean_chain = True
        self.num_nodes = 1
        self.extra_args = [[
            "-datacarriersize=100000",
            "-maxmempool=5",
        ]]
        self.supports_cli = False

    def test_rbf_carveout_disallowed(self):
        node = self.nodes[0]

        self.log.info("Check that individually-evaluated transactions in a package don't increase package limits for other subpackage parts")

        # We set chain limits to 2 ancestors, 1 descendant, then try to get a parents-and-child chain of 2 in mempool
        #
        # A: Solo transaction to be RBF'd (to bump descendant limit for package later)
        # B: First transaction in package, RBFs A by itself under individual evaluation, which would give it +1 descendant limit
        # C: Second transaction in package, spends B. If the +1 descendant limit persisted, would make it into mempool

        self.restart_node(0, extra_args=self.extra_args[0] + ["-limitancestorcount=2", "-limitdescendantcount=1"])

        # Generate a confirmed utxo we will double-spend
        rbf_utxo = self.wallet.send_self_transfer(
            from_node=node,
            confirmed_only=True
        )["new_utxo"]
        self.generate(node, 1)

        # tx_A needs to be RBF'd, set minfee at set size
        A_weight = 1000
        mempoolmin_feerate = node.getmempoolinfo()["mempoolminfee"]
        tx_A = self.wallet.send_self_transfer(
            from_node=node,
            fee=(mempoolmin_feerate / 1000) * (A_weight // 4) + Decimal('0.000001'),
            target_weight=A_weight,
            utxo_to_spend=rbf_utxo,
            confirmed_only=True
        )

        # RBF's tx_A, is not yet submitted
        tx_B = self.wallet.create_self_transfer(
            fee=tx_A["fee"] * 4,
            target_weight=A_weight,
            utxo_to_spend=rbf_utxo,
            confirmed_only=True
        )

        # Spends tx_B's output, too big for cpfp carveout (because that would also increase the descendant limit by 1)
        non_cpfp_carveout_weight = 40001 # EXTRA_DESCENDANT_TX_SIZE_LIMIT + 1
        tx_C = self.wallet.create_self_transfer(
            target_weight=non_cpfp_carveout_weight,
            fee = (mempoolmin_feerate / 1000) * (non_cpfp_carveout_weight // 4) + Decimal('0.000001'),
            utxo_to_spend=tx_B["new_utxo"],
            confirmed_only=True
        )
        res = node.submitpackage([tx_B["hex"], tx_C["hex"]])
        assert_equal(res["package_msg"], "transaction failed")
        assert "too-long-mempool-chain" in res["tx-results"][tx_C["wtxid"]]["error"]

    def test_mid_package_eviction(self):
        node = self.nodes[0]
        self.log.info("Check a package where each parent passes the current mempoolminfee but would cause eviction before package submission terminates")

        self.restart_node(0, extra_args=self.extra_args[0])

        # Restarting the node resets mempool minimum feerate
        assert_equal(node.getmempoolinfo()['minrelaytxfee'], Decimal('0.00001000'))
        assert_equal(node.getmempoolinfo()['mempoolminfee'], Decimal('0.00001000'))

        fill_mempool(self, node)
        current_info = node.getmempoolinfo()
        mempoolmin_feerate = current_info["mempoolminfee"]

        package_hex = []
        # UTXOs to be spent by the ultimate child transaction
        parent_utxos = []

        evicted_weight = 8000
        # Mempool transaction which is evicted due to being at the "bottom" of the mempool when the
        # mempool overflows and evicts by descendant score. It's important that the eviction doesn't
        # happen in the middle of package evaluation, as it can invalidate the coins cache.
        mempool_evicted_tx = self.wallet.send_self_transfer(
            from_node=node,
            fee=(mempoolmin_feerate / 1000) * (evicted_weight // 4) + Decimal('0.000001'),
            target_weight=evicted_weight,
            confirmed_only=True
        )
        # Already in mempool when package is submitted.
        assert mempool_evicted_tx["txid"] in node.getrawmempool()

        # This parent spends the above mempool transaction that exists when its inputs are first
        # looked up, but disappears later. It is rejected for being too low fee (but eligible for
        # reconsideration), and its inputs are cached. When the mempool transaction is evicted, its
        # coin is no longer available, but the cache could still contains the tx.
        cpfp_parent = self.wallet.create_self_transfer(
            utxo_to_spend=mempool_evicted_tx["new_utxo"],
            fee_rate=mempoolmin_feerate - Decimal('0.00001'),
            confirmed_only=True)
        package_hex.append(cpfp_parent["hex"])
        parent_utxos.append(cpfp_parent["new_utxo"])
        assert_equal(node.testmempoolaccept([cpfp_parent["hex"]])[0]["reject-reason"], "mempool min fee not met")

        self.wallet.rescan_utxos()

        # Series of parents that don't need CPFP and are submitted individually. Each one is large and
        # high feerate, which means they should trigger eviction but not be evicted.
        parent_weight = 100000
        num_big_parents = 3
        assert_greater_than(parent_weight * num_big_parents, current_info["maxmempool"] - current_info["bytes"])
        parent_fee = (100 * mempoolmin_feerate / 1000) * (parent_weight // 4)

        big_parent_txids = []
        for i in range(num_big_parents):
            parent = self.wallet.create_self_transfer(fee=parent_fee, target_weight=parent_weight, confirmed_only=True)
            parent_utxos.append(parent["new_utxo"])
            package_hex.append(parent["hex"])
            big_parent_txids.append(parent["txid"])
            # There is room for each of these transactions independently
            assert node.testmempoolaccept([parent["hex"]])[0]["allowed"]

        # Create a child spending everything, bumping cpfp_parent just above mempool minimum
        # feerate. It's important not to bump too much as otherwise mempool_evicted_tx would not be
        # evicted, making this test much less meaningful.
        approx_child_vsize = self.wallet.create_self_transfer_multi(utxos_to_spend=parent_utxos)["tx"].get_vsize()
        cpfp_fee = (mempoolmin_feerate / 1000) * (cpfp_parent["tx"].get_vsize() + approx_child_vsize) - cpfp_parent["fee"]
        # Specific number of satoshis to fit within a small window. The parent_cpfp + child package needs to be
        # - When there is mid-package eviction, high enough feerate to meet the new mempoolminfee
        # - When there is no mid-package eviction, low enough feerate to be evicted immediately after submission.
        magic_satoshis = 1200
        cpfp_satoshis = int(cpfp_fee * COIN) + magic_satoshis

        child = self.wallet.create_self_transfer_multi(utxos_to_spend=parent_utxos, fee_per_output=cpfp_satoshis)
        package_hex.append(child["hex"])

        # Package should be submitted, temporarily exceeding maxmempool, and then evicted.
        with node.assert_debug_log(expected_msgs=["rolling minimum fee bumped"]):
            assert_equal(node.submitpackage(package_hex)["package_msg"], "transaction failed")

        # Maximum size must never be exceeded.
        assert_greater_than(node.getmempoolinfo()["maxmempool"], node.getmempoolinfo()["bytes"])

        # Evicted transaction and its descendants must not be in mempool.
        resulting_mempool_txids = node.getrawmempool()
        assert mempool_evicted_tx["txid"] not in resulting_mempool_txids
        assert cpfp_parent["txid"] not in resulting_mempool_txids
        assert child["txid"] not in resulting_mempool_txids
        for txid in big_parent_txids:
            assert txid in resulting_mempool_txids

    def test_mid_package_replacement(self):
        node = self.nodes[0]
        self.log.info("Check a package where an early tx depends on a later-replaced mempool tx")

        self.restart_node(0, extra_args=self.extra_args[0])

        # Restarting the node resets mempool minimum feerate
        assert_equal(node.getmempoolinfo()['minrelaytxfee'], Decimal('0.00001000'))
        assert_equal(node.getmempoolinfo()['mempoolminfee'], Decimal('0.00001000'))

        fill_mempool(self, node)
        current_info = node.getmempoolinfo()
        mempoolmin_feerate = current_info["mempoolminfee"]

        # Mempool transaction which is evicted due to being at the "bottom" of the mempool when the
        # mempool overflows and evicts by descendant score. It's important that the eviction doesn't
        # happen in the middle of package evaluation, as it can invalidate the coins cache.
        double_spent_utxo = self.wallet.get_utxo(confirmed_only=True)
        replaced_tx = self.wallet.send_self_transfer(
            from_node=node,
            utxo_to_spend=double_spent_utxo,
            fee_rate=mempoolmin_feerate,
            confirmed_only=True
        )
        # Already in mempool when package is submitted.
        assert replaced_tx["txid"] in node.getrawmempool()

        # This parent spends the above mempool transaction that exists when its inputs are first
        # looked up, but disappears later. It is rejected for being too low fee (but eligible for
        # reconsideration), and its inputs are cached. When the mempool transaction is evicted, its
        # coin is no longer available, but the cache could still contain the tx.
        cpfp_parent = self.wallet.create_self_transfer(
            utxo_to_spend=replaced_tx["new_utxo"],
            fee_rate=mempoolmin_feerate - Decimal('0.00001'),
            confirmed_only=True)

        self.wallet.rescan_utxos()

        # Parent that replaces the parent of cpfp_parent.
        replacement_tx = self.wallet.create_self_transfer(
            utxo_to_spend=double_spent_utxo,
            fee_rate=10*mempoolmin_feerate,
            confirmed_only=True
        )
        parent_utxos = [cpfp_parent["new_utxo"], replacement_tx["new_utxo"]]

        # Create a child spending everything, CPFPing the low-feerate parent.
        approx_child_vsize = self.wallet.create_self_transfer_multi(utxos_to_spend=parent_utxos)["tx"].get_vsize()
        cpfp_fee = (2 * mempoolmin_feerate / 1000) * (cpfp_parent["tx"].get_vsize() + approx_child_vsize) - cpfp_parent["fee"]
        child = self.wallet.create_self_transfer_multi(utxos_to_spend=parent_utxos, fee_per_output=int(cpfp_fee * COIN))
        # It's very important that the cpfp_parent is before replacement_tx so that its input (from
        # replaced_tx) is first looked up *before* replacement_tx is submitted.
        package_hex = [cpfp_parent["hex"], replacement_tx["hex"], child["hex"]]

        # Package should be submitted, temporarily exceeding maxmempool, and then evicted.
        res = node.submitpackage(package_hex)
        assert_equal(res["package_msg"], "transaction failed")
        assert len([tx_res for _, tx_res in res["tx-results"].items() if "error" in tx_res and tx_res["error"] == "bad-txns-inputs-missingorspent"])

        # Maximum size must never be exceeded.
        assert_greater_than(node.getmempoolinfo()["maxmempool"], node.getmempoolinfo()["bytes"])

        resulting_mempool_txids = node.getrawmempool()
        # The replacement should be successful.
        assert replacement_tx["txid"] in resulting_mempool_txids
        # The replaced tx and all of its descendants must not be in mempool.
        assert replaced_tx["txid"] not in resulting_mempool_txids
        assert cpfp_parent["txid"] not in resulting_mempool_txids
        assert child["txid"] not in resulting_mempool_txids


    def run_test(self):
        node = self.nodes[0]
        self.wallet = MiniWallet(node)
        miniwallet = self.wallet

        # Generate coins needed to create transactions in the subtests (excluding coins used in fill_mempool).
        self.generate(miniwallet, 20)

        relayfee = node.getnetworkinfo()['relayfee']
        self.log.info('Check that mempoolminfee is minrelaytxfee')
        assert_equal(node.getmempoolinfo()['minrelaytxfee'], Decimal('0.00001000'))
        assert_equal(node.getmempoolinfo()['mempoolminfee'], Decimal('0.00001000'))

        fill_mempool(self, node)

        # Deliberately try to create a tx with a fee less than the minimum mempool fee to assert that it does not get added to the mempool
        self.log.info('Create a mempool tx that will not pass mempoolminfee')
        assert_raises_rpc_error(-26, "mempool min fee not met", miniwallet.send_self_transfer, from_node=node, fee_rate=relayfee)

        self.log.info("Check that submitpackage allows cpfp of a parent below mempool min feerate")
        node = self.nodes[0]
        peer = node.add_p2p_connection(P2PTxInvStore())

        # Package with 2 parents and 1 child. One parent has a high feerate due to modified fees,
        # another is below the mempool minimum feerate but bumped by the child.
        tx_poor = miniwallet.create_self_transfer(fee_rate=relayfee)
        tx_rich = miniwallet.create_self_transfer(fee=0, fee_rate=0)
        node.prioritisetransaction(tx_rich["txid"], 0, int(DEFAULT_FEE * COIN))
        package_txns = [tx_rich, tx_poor]
        coins = [tx["new_utxo"] for tx in package_txns]
        tx_child = miniwallet.create_self_transfer_multi(utxos_to_spend=coins, fee_per_output=10000) #DEFAULT_FEE
        package_txns.append(tx_child)

        submitpackage_result = node.submitpackage([tx["hex"] for tx in package_txns])
        assert_equal(submitpackage_result["package_msg"], "success")

        rich_parent_result = submitpackage_result["tx-results"][tx_rich["wtxid"]]
        poor_parent_result = submitpackage_result["tx-results"][tx_poor["wtxid"]]
        child_result = submitpackage_result["tx-results"][tx_child["tx"].getwtxid()]
        assert_fee_amount(poor_parent_result["fees"]["base"], tx_poor["tx"].get_vsize(), relayfee)
        assert_equal(rich_parent_result["fees"]["base"], 0)
        assert_equal(child_result["fees"]["base"], DEFAULT_FEE)
        # The "rich" parent does not require CPFP so its effective feerate is just its individual feerate.
        assert_fee_amount(DEFAULT_FEE, tx_rich["tx"].get_vsize(), rich_parent_result["fees"]["effective-feerate"])
        assert_equal(rich_parent_result["fees"]["effective-includes"], [tx_rich["wtxid"]])
        # The "poor" parent and child's effective feerates are the same, composed of their total
        # fees divided by their combined vsize.
        package_fees = poor_parent_result["fees"]["base"] + child_result["fees"]["base"]
        package_vsize = tx_poor["tx"].get_vsize() + tx_child["tx"].get_vsize()
        assert_fee_amount(package_fees, package_vsize, poor_parent_result["fees"]["effective-feerate"])
        assert_fee_amount(package_fees, package_vsize, child_result["fees"]["effective-feerate"])
        assert_equal([tx_poor["wtxid"], tx_child["tx"].getwtxid()], poor_parent_result["fees"]["effective-includes"])
        assert_equal([tx_poor["wtxid"], tx_child["tx"].getwtxid()], child_result["fees"]["effective-includes"])

        # The node will broadcast each transaction, still abiding by its peer's fee filter
        peer.wait_for_broadcast([tx["tx"].getwtxid() for tx in package_txns])

        self.log.info("Check a package that passes mempoolminfee but is evicted immediately after submission")
        mempoolmin_feerate = node.getmempoolinfo()["mempoolminfee"]
        current_mempool = node.getrawmempool(verbose=False)
        worst_feerate_btcvb = Decimal("21000000")
        for txid in current_mempool:
            entry = node.getmempoolentry(txid)
            worst_feerate_btcvb = min(worst_feerate_btcvb, entry["fees"]["descendant"] / entry["descendantsize"])
        # Needs to be large enough to trigger eviction
        target_weight_each = 200000
        assert_greater_than(target_weight_each * 2, node.getmempoolinfo()["maxmempool"] - node.getmempoolinfo()["bytes"])
        # Should be a true CPFP: parent's feerate is just below mempool min feerate
        parent_fee = (mempoolmin_feerate / 1000) * (target_weight_each // 4) - Decimal("0.00001")
        # Parent + child is above mempool minimum feerate
        child_fee = (worst_feerate_btcvb) * (target_weight_each // 4) - Decimal("0.00001")
        # However, when eviction is triggered, these transactions should be at the bottom.
        # This assertion assumes parent and child are the same size.
        miniwallet.rescan_utxos()
        tx_parent_just_below = miniwallet.create_self_transfer(fee=parent_fee, target_weight=target_weight_each)
        tx_child_just_above = miniwallet.create_self_transfer(utxo_to_spend=tx_parent_just_below["new_utxo"], fee=child_fee, target_weight=target_weight_each)
        # This package ranks below the lowest descendant package in the mempool
        assert_greater_than(worst_feerate_btcvb, (parent_fee + child_fee) / (tx_parent_just_below["tx"].get_vsize() + tx_child_just_above["tx"].get_vsize()))
        assert_greater_than(mempoolmin_feerate, (parent_fee) / (tx_parent_just_below["tx"].get_vsize()))
        assert_greater_than((parent_fee + child_fee) / (tx_parent_just_below["tx"].get_vsize() + tx_child_just_above["tx"].get_vsize()), mempoolmin_feerate / 1000)
        res = node.submitpackage([tx_parent_just_below["hex"], tx_child_just_above["hex"]])
        for wtxid in [tx_parent_just_below["wtxid"], tx_child_just_above["wtxid"]]:
            assert_equal(res["tx-results"][wtxid]["error"], "mempool full")

        self.log.info('Test passing a value below the minimum (5 MB) to -maxmempool throws an error')
        self.stop_node(0)
        self.nodes[0].assert_start_raises_init_error(["-maxmempool=4"], "Error: -maxmempool must be at least 5 MB")

        self.test_mid_package_replacement()
        self.test_mid_package_eviction()
        self.test_rbf_carveout_disallowed()


if __name__ == '__main__':
    MempoolLimitTest().main()