Files
plm-lottery/tests/unit/test_broadcast.py
T
davide 17c557b8a3 Meet BIP125's relay minimum on every RBF bump, and cap the fee rate (B-32)
bump_fee computed fee_delta as new_fee - old_fee, falling back to a
flat 1-satoshi bump whenever that came out zero or negative - which
happened whenever old_fee (the actual fee paid, from real prevout
amounts) already exceeded the naive target, e.g. because dust change
had been folded into the original fee (psbt_builder.py's
DUST_LIMIT_SATS handling). A 1-satoshi total increase is nowhere near
BIP125 rule 4's minimum (the replacement must pay at least the
incremental relay fee rate times its own vsize more than what it
replaces), so the node rejected it every time - and since bump_fee
raised before touching `pending`, the next tick retried with identical
parameters every 30 seconds, forever. Separately, the fee rate climbed
by 1 sat/vB every bump with no ceiling.

fee_delta is now max(target_fee - old_fee, vsize * the incremental
relay rate) - always at least the relay-mandated minimum regardless of
what the naive arithmetic produces. pending.fee_rate_sat_vb is set to
the actual resulting rate rather than the naive target, so a later
bump's arithmetic starts from what's really being paid instead of
drifting from it. Once a transaction reaches MAX_FEE_RATE_SAT_VB (a
new constant, 10,000 sat/vB, shared with RoundConfig.fee_rate_sat_vb's
existing admin-facing bound so the two can't drift apart - the same
reason MIN_PASSWORD_LENGTH is shared elsewhere) bump_fee refuses to
bump further; the reconciler abandons it if it never confirms (B-27)
instead of this retrying forever.

Suite grows from 185 to 187 tests. BUGS.md moves B-32 to Previously
fixed.
2026-07-27 11:16:20 +02:00

451 lines
18 KiB
Python

from datetime import datetime, timedelta, timezone
import pytest
from embit import script
from embit.bip32 import HDKey
from embit.transaction import Transaction
from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
from app.config import settings
from app.db.base import Base
from app.db.models import PendingTransaction, User
from app.tx.broadcast import RbfError, bump_fee, should_bump
from app.wallet.plm_network import PLM_MAINNET
from app.wallet.psbt_builder import MAX_FEE_RATE_SAT_VB, Utxo, build_signed_transaction, estimate_vsize
def _key(seed_byte: int) -> HDKey:
root = HDKey.from_seed(bytes([seed_byte]) * 32, version=PLM_MAINNET["xprv"])
return root.derive("m/84h/746h/0h/0/0")
def test_should_bump_false_before_timeout():
pending = PendingTransaction(
kind="bet", current_txid="x", fee_rate_sat_vb=1, raw_tx_hex="00", status="pending",
broadcast_at=datetime.now(timezone.utc), last_broadcast_at=datetime.now(timezone.utc),
)
assert should_bump(pending, datetime.now(timezone.utc), timeout_seconds=900) is False
def test_should_bump_true_after_timeout():
pending = PendingTransaction(
kind="bet", current_txid="x", fee_rate_sat_vb=1, raw_tx_hex="00", status="pending",
broadcast_at=datetime.now(timezone.utc) - timedelta(seconds=1000),
last_broadcast_at=datetime.now(timezone.utc) - timedelta(seconds=1000),
)
assert should_bump(pending, datetime.now(timezone.utc), timeout_seconds=900) is True
def test_should_bump_false_when_not_pending():
pending = PendingTransaction(
kind="bet", current_txid="x", fee_rate_sat_vb=1, raw_tx_hex="00", status="confirmed",
broadcast_at=datetime.now(timezone.utc) - timedelta(seconds=1000),
last_broadcast_at=datetime.now(timezone.utc) - timedelta(seconds=1000),
)
assert should_bump(pending, datetime.now(timezone.utc), timeout_seconds=900) is False
def test_should_bump_measures_from_last_broadcast_not_first(monkeypatch):
"""B-27 regression: a tx first broadcast long ago, but bumped recently, must not
be due for another bump yet — should_bump has to look at last_broadcast_at, not
the original broadcast_at, or every tick would try to re-bump it."""
pending = PendingTransaction(
kind="bet", current_txid="x", fee_rate_sat_vb=1, raw_tx_hex="00", status="pending",
broadcast_at=datetime.now(timezone.utc) - timedelta(seconds=10_000),
last_broadcast_at=datetime.now(timezone.utc),
)
assert should_bump(pending, datetime.now(timezone.utc), timeout_seconds=900) is False
class FakeClient:
def __init__(self, prevout_values: dict[str, int]):
self._prevout_values = prevout_values
self.broadcasted: list[str] = []
async def get_transaction(self, txid: str, verbose: bool = False) -> dict:
return {"vout": {0: {"value": self._prevout_values[txid] / 100_000_000}}}
async def broadcast(self, raw_tx_hex: str) -> str:
self.broadcasted.append(raw_tx_hex)
return "network-txid"
@pytest.fixture
async def session_factory(tmp_path, monkeypatch):
monkeypatch.setattr(settings, "master_key_path", str(tmp_path / "master.xprv.enc"))
monkeypatch.setattr(
settings,
"xprv_encryption_key",
__import__("cryptography.fernet", fromlist=["Fernet"]).Fernet.generate_key().decode(),
)
from app.wallet import hd
hd._account_key = None
hd.generate_master_key()
engine = create_async_engine("sqlite+aiosqlite:///:memory:")
async with engine.begin() as conn:
await conn.run_sync(Base.metadata.create_all)
yield async_sessionmaker(engine, expire_on_commit=False)
await engine.dispose()
hd._account_key = None
async def test_bump_fee_shrinks_change_and_rebroadcasts(session_factory):
from app.wallet.hd import derive_user_address, derive_user_key
signer = derive_user_key(0)
my_address = derive_user_address(0)
from_script = script.p2wpkh(signer.to_public())
to_address = script.p2wpkh(_key(99).to_public()).address(network=PLM_MAINNET)
utxo_amount = 150_000_000
utxo_txid = "11" * 32
built = build_signed_transaction(
signing_key=signer,
from_script=from_script,
utxos=[Utxo(utxo_txid, 0, utxo_amount)],
to_address=to_address,
amount_sats=10_000_000,
change_address=my_address,
fee_rate_sat_vb=1,
)
async with session_factory() as session:
user = User(username="alice", password_hash="x", derivation_index=0, address=my_address)
session.add(user)
await session.commit()
pending = PendingTransaction(
kind="bet",
user_id=user.id,
current_txid=built.txid,
fee_rate_sat_vb=1,
raw_tx_hex=built.raw_hex,
status="pending",
broadcast_at=datetime.now(timezone.utc) - timedelta(seconds=1000),
)
session.add(pending)
await session.commit()
pending_id = pending.id
client = FakeClient({utxo_txid: utxo_amount})
async with session_factory() as session:
row = await session.get(PendingTransaction, pending_id)
new_txid = await bump_fee(session, client, row)
assert client.broadcasted
assert new_txid != built.txid
new_tx = Transaction.parse(bytes.fromhex(client.broadcasted[0]))
old_tx = Transaction.parse(bytes.fromhex(built.raw_hex))
old_change = next(o.value for o in old_tx.vout if o.script_pubkey.address(network=PLM_MAINNET) == my_address)
new_change = next(o.value for o in new_tx.vout if o.script_pubkey.address(network=PLM_MAINNET) == my_address)
assert new_change < old_change # fee bump came out of the change output
async with session_factory() as session:
row = await session.get(PendingTransaction, pending_id)
assert row.current_txid == new_txid
assert row.fee_rate_sat_vb == 2
assert row.attempt_count == 2
async def test_bump_fee_leaves_broadcast_at_untouched(session_factory):
"""B-27 regression: bump_fee must only ever update last_broadcast_at. Before
this, it overwrote broadcast_at on every bump — the same field
tx/reconcile.py's abandon-after-N-hours grace period measures from — so a
repeatedly-bumped-but-never-mined tx reset that clock forever and was never
abandoned."""
from app.wallet.hd import derive_user_address, derive_user_key
signer = derive_user_key(0)
my_address = derive_user_address(0)
from_script = script.p2wpkh(signer.to_public())
to_address = script.p2wpkh(_key(97).to_public()).address(network=PLM_MAINNET)
utxo_amount = 150_000_000
utxo_txid = "33" * 32
built = build_signed_transaction(
signing_key=signer,
from_script=from_script,
utxos=[Utxo(utxo_txid, 0, utxo_amount)],
to_address=to_address,
amount_sats=10_000_000,
change_address=my_address,
fee_rate_sat_vb=1,
)
original_broadcast_at = datetime.now(timezone.utc) - timedelta(days=1)
async with session_factory() as session:
user = User(username="carol", password_hash="x", derivation_index=0, address=my_address)
session.add(user)
await session.commit()
pending = PendingTransaction(
kind="bet",
user_id=user.id,
current_txid=built.txid,
fee_rate_sat_vb=1,
raw_tx_hex=built.raw_hex,
status="pending",
broadcast_at=original_broadcast_at,
last_broadcast_at=original_broadcast_at,
)
session.add(pending)
await session.commit()
pending_id = pending.id
client = FakeClient({utxo_txid: utxo_amount})
before_bump = datetime.now(timezone.utc)
async with session_factory() as session:
row = await session.get(PendingTransaction, pending_id)
await bump_fee(session, client, row)
async with session_factory() as session:
row = await session.get(PendingTransaction, pending_id)
assert row.broadcast_at.replace(tzinfo=timezone.utc) == original_broadcast_at
assert row.last_broadcast_at.replace(tzinfo=timezone.utc) >= before_bump
async def test_bump_fee_raises_when_no_change_output(session_factory):
from app.wallet.hd import derive_user_address, derive_user_key
signer = derive_user_key(0)
my_address = derive_user_address(0)
from_script = script.p2wpkh(signer.to_public())
to_address = script.p2wpkh(_key(98).to_public()).address(network=PLM_MAINNET)
utxo_amount = 10_000_000 # exact amount, no change output
utxo_txid = "22" * 32
built = build_signed_transaction(
signing_key=signer,
from_script=from_script,
utxos=[Utxo(utxo_txid, 0, utxo_amount)],
to_address=to_address,
amount_sats=10_000_000,
change_address=my_address,
fee_rate_sat_vb=1,
)
async with session_factory() as session:
user = User(username="bob", password_hash="x", derivation_index=0, address=my_address)
session.add(user)
await session.commit()
pending = PendingTransaction(
kind="bet",
user_id=user.id,
current_txid=built.txid,
fee_rate_sat_vb=1,
raw_tx_hex=built.raw_hex,
status="pending",
broadcast_at=datetime.now(timezone.utc) - timedelta(seconds=1000),
)
session.add(pending)
await session.commit()
pending_id = pending.id
client = FakeClient({utxo_txid: utxo_amount})
async with session_factory() as session:
row = await session.get(PendingTransaction, pending_id)
with pytest.raises(RbfError):
await bump_fee(session, client, row)
async def test_bump_fee_retargets_every_stored_txid(session_factory):
"""B-02/B-20: a bump changes the txid, and everything that recorded the old one
has to follow — the participant's bet_txid (whose staleness used to wedge the
round forever), the UTXO's spent_txid (which the reconciler matches on), and
replaced_by_txid, which was never written at all."""
from app.db.models import Round, RoundParticipant, UtxoEvent
from app.wallet.hd import derive_user_address, derive_user_key
signer = derive_user_key(0)
my_address = derive_user_address(0)
from_script = script.p2wpkh(signer.to_public())
to_address = script.p2wpkh(_key(98).to_public()).address(network=PLM_MAINNET)
utxo_amount = 150_000_000
utxo_txid = "22" * 32
built = build_signed_transaction(
signing_key=signer,
from_script=from_script,
utxos=[Utxo(utxo_txid, 0, utxo_amount)],
to_address=to_address,
amount_sats=10_000_000,
change_address=my_address,
fee_rate_sat_vb=1,
)
async with session_factory() as session:
user = User(username="bob", password_hash="x", derivation_index=0, address=my_address)
session.add(user)
session.add(Round(id=1, status="open"))
await session.flush()
session.add(
UtxoEvent(
user_id=user.id, txid=utxo_txid, vout=0, amount_sats=utxo_amount,
confirmed_height=5, spent_txid=built.txid,
)
)
session.add(
RoundParticipant(
round_id=1, user_id=user.id, bet_amount_sats=built.recipient_sats,
bet_txid=built.txid, status="broadcast",
)
)
pending = PendingTransaction(
kind="bet", round_id=1, user_id=user.id, current_txid=built.txid, fee_rate_sat_vb=1,
raw_tx_hex=built.raw_hex, status="pending",
broadcast_at=datetime.now(timezone.utc) - timedelta(seconds=1000),
)
session.add(pending)
await session.commit()
pending_id = pending.id
async with session_factory() as session:
row = await session.get(PendingTransaction, pending_id)
new_txid = await bump_fee(session, FakeClient({utxo_txid: utxo_amount}), row)
async with session_factory() as session:
from sqlalchemy import select
row = await session.get(PendingTransaction, pending_id)
assert row.current_txid == new_txid
assert row.replaced_by_txid == built.txid # points backwards at what it replaced
participant = (await session.scalars(select(RoundParticipant))).one()
assert participant.bet_txid == new_txid
utxo = (await session.scalars(select(UtxoEvent))).one()
assert utxo.spent_txid == new_txid
# --- B-32: the bump delta must always meet BIP125's relay-mandated minimum, and
# escalation must stop at a ceiling instead of retrying forever. ------------------
async def test_bump_fee_meets_bip125_minimum_when_old_fee_already_exceeds_target(session_factory):
"""old_fee (as bump_fee computes it from the actual prevout amounts) can end
up higher than vsize * target_fee_rate — e.g. because dust change was folded
into the original fee (wallet/psbt_builder.py's DUST_LIMIT_SATS handling).
The naive `target_fee - old_fee` goes negative in that case; the previous
fallback was a flat 1-satoshi total bump, nowhere near BIP125 rule 4's
required minimum, so the node rejected it every time and — since bump_fee
raised before touching `pending` — the next tick retried identically every
30 seconds, forever. Simulated here by reporting a prevout inflated beyond
what was actually spent, which has the same effect on old_fee as dust
absorption would."""
from app.wallet.hd import derive_user_address, derive_user_key
signer = derive_user_key(0)
my_address = derive_user_address(0)
from_script = script.p2wpkh(signer.to_public())
to_address = script.p2wpkh(_key(96).to_public()).address(network=PLM_MAINNET)
utxo_amount = 150_000_000
utxo_txid = "55" * 32
built = build_signed_transaction(
signing_key=signer,
from_script=from_script,
utxos=[Utxo(utxo_txid, 0, utxo_amount)],
to_address=to_address,
amount_sats=10_000_000,
change_address=my_address,
fee_rate_sat_vb=1,
)
async with session_factory() as session:
user = User(username="dave", password_hash="x", derivation_index=0, address=my_address)
session.add(user)
await session.commit()
pending = PendingTransaction(
kind="bet",
user_id=user.id,
current_txid=built.txid,
fee_rate_sat_vb=1,
raw_tx_hex=built.raw_hex,
status="pending",
broadcast_at=datetime.now(timezone.utc) - timedelta(seconds=1000),
)
session.add(pending)
await session.commit()
pending_id = pending.id
# Reports a prevout inflated well beyond what was actually spent — has the
# same effect on old_fee as dust absorption would have: old_fee ends up far
# above vsize * target_fee_rate (target_fee_rate = 2 here).
inflated_excess = 50_000
client = FakeClient({utxo_txid: utxo_amount + inflated_excess})
async with session_factory() as session:
row = await session.get(PendingTransaction, pending_id)
new_txid = await bump_fee(session, client, row)
assert client.broadcasted
new_tx = Transaction.parse(bytes.fromhex(client.broadcasted[0]))
old_tx = Transaction.parse(bytes.fromhex(built.raw_hex))
old_change = next(o.value for o in old_tx.vout if o.script_pubkey.address(network=PLM_MAINNET) == my_address)
new_change = next(o.value for o in new_tx.vout if o.script_pubkey.address(network=PLM_MAINNET) == my_address)
vsize = estimate_vsize(len(old_tx.vin), len(old_tx.vout))
min_valid_delta = vsize * 1 # BIP125 rule 4's floor at a 1 sat/vB incremental relay fee
assert min_valid_delta > 1 # meaningfully more than the old flat "1 satoshi" fallback
assert old_change - new_change == min_valid_delta
async with session_factory() as session:
row = await session.get(PendingTransaction, pending_id)
old_fee_as_bump_fee_computed_it = built.fee_sats + inflated_excess
expected_rate = (old_fee_as_bump_fee_computed_it + min_valid_delta) // vsize
assert row.fee_rate_sat_vb == expected_rate
assert row.fee_rate_sat_vb > 2 # the actual rate, not the naive (and too-low) target
async def test_bump_fee_refuses_once_at_the_max_fee_rate(session_factory):
"""Without a ceiling, a stuck transaction's fee rate climbed by 1 sat/vB every
30 seconds forever, eating further and further into the user's change."""
from app.wallet.hd import derive_user_address, derive_user_key
signer = derive_user_key(0)
my_address = derive_user_address(0)
from_script = script.p2wpkh(signer.to_public())
to_address = script.p2wpkh(_key(95).to_public()).address(network=PLM_MAINNET)
utxo_amount = 150_000_000
utxo_txid = "66" * 32
built = build_signed_transaction(
signing_key=signer,
from_script=from_script,
utxos=[Utxo(utxo_txid, 0, utxo_amount)],
to_address=to_address,
amount_sats=10_000_000,
change_address=my_address,
fee_rate_sat_vb=1,
)
async with session_factory() as session:
user = User(username="erin", password_hash="x", derivation_index=0, address=my_address)
session.add(user)
await session.commit()
pending = PendingTransaction(
kind="bet",
user_id=user.id,
current_txid=built.txid,
fee_rate_sat_vb=MAX_FEE_RATE_SAT_VB,
raw_tx_hex=built.raw_hex,
status="pending",
broadcast_at=datetime.now(timezone.utc) - timedelta(seconds=1000),
)
session.add(pending)
await session.commit()
pending_id = pending.id
client = FakeClient({utxo_txid: utxo_amount})
async with session_factory() as session:
row = await session.get(PendingTransaction, pending_id)
with pytest.raises(RbfError):
await bump_fee(session, client, row)
assert not client.broadcasted