The poller and the reconciler matched current_txid only. If an earlier version of a bumped transaction confirmed it was never seen, and after 6h the row was abandoned: a confirmed bet's participant deleted, a sent withdrawal marked failed, a paid payout rebuilt. bump_fee also broadcast in phase 2 and persisted in phase 3 unconditionally, so a crash or a `database is locked` in between left a transaction on the network that the DB did not know, and an abandon or a confirmation in the meantime was overwritten. - New table pending_transaction_txids (migration a3f5c2d9b7e1; txid unique, index on the owning row; existing rows backfilled with current_txid + raw and the txid their last bump replaced, raw_hex empty). Written with the row by place_bet, request_withdrawal and _trigger_payout; removed with a bet row that a verified refusal deletes (DAT-38). - bump_fee in four phases: read, build and sign, commit the replacement as a candidate version, broadcast (verdict of B-76, fanned out when accepted; an explicit refusal raises RbfError and leaves the row), then switch the row over with `UPDATE ... WHERE status='pending' AND current_txid=<replaced>`. Zero rows matched is a logged conflict: nothing is overwritten and the candidate stays recorded. An uncertain broadcast adopts the replacement. A retry rebuilds the same candidate without tripping the unique txid. - poll_once and reconcile_once look for every txid of a row. When the version found is not the current one, broadcast.adopt_version makes it current (raw tx included) and retargets spent_txid, bet_txid, withdrawals.txid and payout_txid as a bump does, before the confirmation handler runs. _release_inputs frees inputs claimed by any version of the row. - RbfBumper takes the listener as `network`. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
373 lines
19 KiB
Python
373 lines
19 KiB
Python
import asyncio
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import logging
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from datetime import datetime, timedelta, timezone
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from embit import script
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from embit.psbt import PSBT
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from embit.transaction import Transaction, TransactionInput, TransactionOutput
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from embit.finalizer import finalize_psbt
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from sqlalchemy import select, update
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from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
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from app.db.base import begin_immediate
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from app.db.models import (
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PendingTransaction,
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PendingTransactionTxid,
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Round,
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RoundParticipant,
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User,
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UtxoEvent,
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Withdrawal,
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)
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from app.electrum.client import ElectrumClient
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from app.rounds.config import get_round_config
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from app.tx.outcome import BroadcastOutcome, TransactionNetwork, broadcast_with_verdict
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from app.tx.versions import record_version
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from app.wallet.hd import derive_round_pool_key, derive_user_key
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from app.wallet.plm_network import PLM_MAINNET
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from app.wallet.psbt_builder import MAX_FEE_RATE_SAT_VB, RBF_SEQUENCE, estimate_vsize
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logger = logging.getLogger(__name__)
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_POLL_INTERVAL_SECONDS = 30
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_FEE_RATE_INCREMENT = 1 # how much pending.fee_rate_sat_vb's *target* rises by per bump
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# BIP125 rule 4: a replacement transaction must pay at least this much more, in
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# total, per vbyte of its own size, than the transaction it replaces — Bitcoin
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# Core's default incremental relay fee. bump_fee's delta must never fall below
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# this regardless of what the target-rate arithmetic comes out to (B-32).
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_INCREMENTAL_RELAY_FEE_RATE_SAT_VB = 1
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class RbfError(Exception):
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pass
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def should_bump(pending: PendingTransaction, now: datetime, timeout_seconds: int) -> bool:
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"""Pure decision: has this pending tx gone unconfirmed for longer than the
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configured timeout (RoundConfig.rbf_timeout_seconds) *since it was last
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broadcast*? Kept separate from the I/O-heavy bump_fee() so it's trivially
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unit-testable.
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Deliberately measured from last_broadcast_at, not broadcast_at: this decides
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whether *another* bump is due, which should reset after every bump (a tx just
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rebroadcast at a higher fee deserves the same grace period again) — unlike
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reconcile.py's abandon check, which must measure from the *first* broadcast so
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repeated bumping can't indefinitely postpone ever giving up on a tx (B-27)."""
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if pending.status != "pending":
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return False
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return now >= pending.last_broadcast_at.replace(tzinfo=timezone.utc) + timedelta(seconds=timeout_seconds)
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async def _signing_context(
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session: AsyncSession, kind: str, user_id: int | None, round_id: int | None = None
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) -> tuple:
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"""Returns (signing_key, own_script, own_address) for the single sender that
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controls every input of this tx — a user for bet/withdrawal, the pool for
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payout (the round's own pool key, B-80). All our builders only ever spend one
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address's UTXOs per tx."""
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if kind == "payout":
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round_ = await session.get(Round, round_id) if round_id is not None else None
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if round_ is None or not round_.pool_address:
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raise RbfError(f"payout of round {round_id}: the round has no pool address")
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key = derive_round_pool_key(round_.id, round_.pool_address)
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else:
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user = await session.get(User, user_id)
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key = derive_user_key(user.derivation_index)
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own_script = script.p2wpkh(key.to_public())
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own_address = own_script.address(network=PLM_MAINNET)
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return key, own_script, own_address
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async def _prevout_amount(client: ElectrumClient, vin: TransactionInput) -> int:
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"""The exact integer satoshi value of the output this input spends.
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Parsed directly from the raw transaction via embit rather than asking the
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server for its own float, whole-coin-denominated "value" field (verbose=True)
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and converting with `* 100_000_000` — embit's TransactionOutput.value is
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already an integer number of satoshis straight from the tx's binary
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encoding, so this never touches floating point in a codebase that is
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otherwise strictly integer-satoshi (B-40).
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"""
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txid_hex = vin.txid.hex()
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raw_hex = await client.get_transaction(txid_hex, verbose=False)
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prevout_tx = Transaction.parse(bytes.fromhex(raw_hex))
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return prevout_tx.vout[vin.vout].value
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def _find_change_output(tx: Transaction, change_address: str) -> int | None:
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for i, out in enumerate(tx.vout):
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if out.script_pubkey.address(network=PLM_MAINNET) == change_address:
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return i
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return None
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async def bump_fee(
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session_factory: async_sessionmaker,
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client: ElectrumClient,
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pending_id: int,
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network: TransactionNetwork | None = None,
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) -> str | None:
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"""Rebuild pending_transaction `pending_id`'s transaction with a higher fee
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(same inputs, same recipient outputs, the extra fee taken from the change
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output) and rebroadcast. Returns the new txid, or None if there was nothing
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to do (the row is gone or already left "pending" — a normal race with
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confirmation, not an error, or a conflict recorded below).
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Four phases, so no DB session is held across the network calls this needs
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(one get_transaction per input, then a broadcast) — the same shape used
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elsewhere for exactly this reason (B-18, rounds/scheduler.py:_trigger_payout;
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B-31, electrum/listener.py:refresh_user) and now here too (B-40): read what's
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needed and close the session, do the chain work, then reopen to persist.
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B-77 (TX-12, TX-13, DAT-34): the replacement is **written before it is broadcast**.
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It used to be sent in the chain phase and recorded afterwards, unconditionally, so
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a crash or a `database is locked` in between left a transaction on the network
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that the database did not know, and an abandon or a confirmation that happened in
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the meantime was silently overwritten. Now the signed replacement is committed as
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a *candidate* version (pending_transaction_txids) first; a candidate that is never
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broadcast is harmless, and one that is — and then confirms — is recognised like any
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other version. After the broadcast the row is switched over with a conditional
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UPDATE (status still pending, current_txid still the one replaced); zero rows
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matched is a conflict: the row is left alone, the candidate stays recorded, and
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the reconciler resolves it.
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Only handles the common case: exactly one change output paying back to the
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tx's own sender address, large enough to absorb the increase. If there's no
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such output (e.g. an exact-amount bet with no change), this raises RbfError —
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bumping such a tx would require selecting additional inputs, which isn't
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implemented for the MVP; it needs manual operator intervention. Also raises
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RbfError, rather than bumping, once the row is already at MAX_FEE_RATE_SAT_VB
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(B-32), and when the network explicitly refuses the replacement (TX-24).
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"""
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# --- Phase 1: read what's needed, close the session before any network call ---
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async with session_factory() as session:
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pending = await session.get(PendingTransaction, pending_id)
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if pending is None or pending.status != "pending":
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logger.info("pending_transaction %s no longer pending; skipping bump", pending_id)
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return None
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if pending.fee_rate_sat_vb >= MAX_FEE_RATE_SAT_VB:
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raise RbfError(
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f"pending_transaction {pending_id}: already at the maximum fee rate "
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f"({MAX_FEE_RATE_SAT_VB} sat/vB) — refusing to bump further"
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)
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kind = pending.kind
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current_fee_rate = pending.fee_rate_sat_vb
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raw_tx_hex = pending.raw_tx_hex
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old_txid = pending.current_txid
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signing_key, own_script, own_address = await _signing_context(session, kind, pending.user_id, pending.round_id)
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# --- Phase 2: chain reads and signing — no DB session open, nothing sent yet ---
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old_tx = Transaction.parse(bytes.fromhex(raw_tx_hex))
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input_amounts = [await _prevout_amount(client, vin) for vin in old_tx.vin]
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total_in = sum(input_amounts)
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old_fee = total_in - sum(o.value for o in old_tx.vout)
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vsize = estimate_vsize(len(old_tx.vin), len(old_tx.vout))
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target_fee_rate = min(current_fee_rate + _FEE_RATE_INCREMENT, MAX_FEE_RATE_SAT_VB)
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target_fee = vsize * target_fee_rate
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# BIP125 rule 4's minimum, in absolute sats for this tx's size — the floor
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# `fee_delta` must never go below, no matter what `target_fee - old_fee` comes
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# out to. That naive difference used to go to zero or negative whenever
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# old_fee already exceeded target_fee (e.g. a dust change amount folded into
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# the original fee — wallet/psbt_builder.py's DUST_LIMIT_SATS handling), and
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# the previous fallback — a flat 1-satoshi total bump — was nowhere near this
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# relay-mandated minimum, so the node rejected it every time. Because bump_fee
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# raised before touching `pending`, the next tick retried with identical
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# parameters every 30 seconds, forever (B-32).
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min_valid_delta = vsize * _INCREMENTAL_RELAY_FEE_RATE_SAT_VB
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fee_delta = max(target_fee - old_fee, min_valid_delta)
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change_index = _find_change_output(old_tx, own_address)
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if change_index is None or old_tx.vout[change_index].value <= fee_delta:
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raise RbfError(f"pending_transaction {pending_id}: no change output large enough to absorb a fee bump")
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new_vout = list(old_tx.vout)
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bumped_change = new_vout[change_index].value - fee_delta
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new_vout[change_index] = TransactionOutput(bumped_change, new_vout[change_index].script_pubkey)
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new_vin = [TransactionInput(v.txid, v.vout, sequence=RBF_SEQUENCE) for v in old_tx.vin]
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new_tx = Transaction(vin=new_vin, vout=new_vout)
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psbt = PSBT(new_tx)
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for i, amount in enumerate(input_amounts):
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psbt.inputs[i].witness_utxo = TransactionOutput(amount, own_script)
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signed = psbt.sign_with(signing_key)
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if signed != len(new_vin):
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raise RuntimeError(f"expected {len(new_vin)} signatures, got {signed}")
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final_tx = finalize_psbt(psbt)
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if final_tx is None:
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raise RuntimeError("failed to finalize bumped PSBT")
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raw_hex = final_tx.serialize().hex()
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new_txid = final_tx.txid().hex()
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# --- Phase 3: record the replacement as a candidate, *then* broadcast ----------
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async with session_factory() as session:
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await begin_immediate(session) # B-88
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pending = await session.get(PendingTransaction, pending_id)
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if pending is None or pending.status != "pending" or pending.current_txid != old_txid:
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logger.info("pending_transaction %s changed while its bump was being built; skipping", pending_id)
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return None
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await record_version(session, pending, new_txid, raw_hex) # B-77 (TX-12, DAT-71)
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await session.commit()
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verdict = await broadcast_with_verdict(client, network, raw_hex, new_txid) # B-76: also fans out
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if verdict.outcome is BroadcastOutcome.REFUSED:
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# The network explicitly refused the replacement and no server knows it: the row
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# is unchanged and keeps the version that is on the network (TX-24). The
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# candidate stays recorded — it was never relayed, so nobody will confirm it.
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raise RbfError(f"pending_transaction {pending_id}: the network refused the replacement: {verdict.reason}")
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# ACCEPTED, or UNCERTAIN: the replacement may well be on the network, so the row
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# follows it (TX-12); the old version stays recorded and is still recognised should
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# it be the one that confirms.
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# --- Phase 4: switch the row over, conditionally --------------------------------
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async with session_factory() as session:
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await begin_immediate(session) # B-88
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# The *actual* resulting rate, not target_fee_rate: when the BIP125-minimum
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# floor above raised fee_delta past the naive target, the tx now pays more
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# than target_fee_rate implied. Recording the true rate keeps the next bump's
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# arithmetic honest instead of drifting from what's really being paid.
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# last_broadcast_at, not broadcast_at (B-27): broadcast_at must stay the *first*
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# broadcast, since reconcile.py's abandon-after-N-hours grace period is measured
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# from it — overwriting it here used to reset that clock on every bump, so a
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# repeatedly-bumped-but-never-mined tx was never abandoned.
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result = await session.execute(
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update(PendingTransaction)
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.where(
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PendingTransaction.id == pending_id,
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PendingTransaction.status == "pending",
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PendingTransaction.current_txid == old_txid,
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)
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.values(
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replaced_by_txid=old_txid, # points backwards: what current_txid replaced
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current_txid=new_txid,
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raw_tx_hex=raw_hex,
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fee_rate_sat_vb=(old_fee + fee_delta) // vsize,
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attempt_count=PendingTransaction.attempt_count + 1,
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last_broadcast_at=datetime.now(timezone.utc),
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)
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.execution_options(synchronize_session=False)
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)
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if result.rowcount != 1:
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# Confirmed, abandoned or already re-bumped while we were broadcasting. The
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# row is not overwritten; the candidate is still recorded, and confirmation
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# and reconciliation look for it like any other version (TX-13).
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await session.rollback()
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logger.warning(
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"bump of pending_transaction %s: the row changed during the broadcast (replaced %s by %s); "
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"left to the reconciler",
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pending_id,
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old_txid,
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new_txid,
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)
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return None
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pending = await session.get(PendingTransaction, pending_id)
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await _retarget_txid_references(session, pending, old_txid, new_txid)
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await session.commit()
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logger.info("bumped %s pending_transaction %s: %s -> %s", kind, pending_id, old_txid, new_txid)
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return new_txid
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async def adopt_version(session: AsyncSession, pending: PendingTransaction, txid: str) -> None:
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"""The network confirmed (or holds) a version of this row other than the current one
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— an earlier version of a bumped transaction, or a candidate whose switch-over never
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happened (B-77, TX-19, DAT-14). `current_txid` and `raw_tx_hex` become that
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version's, and the txid is propagated everywhere it is recorded, exactly as after a
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bump; without it the inputs of a replaced transaction would no longer be
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recognised as the row's (DAT-13)."""
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if txid == pending.current_txid:
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return
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version = await session.scalar(
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select(PendingTransactionTxid).where(
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PendingTransactionTxid.txid == txid, PendingTransactionTxid.pending_transaction_id == pending.id
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)
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)
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old_txid = pending.current_txid
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pending.replaced_by_txid = old_txid
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pending.current_txid = txid
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if version is not None and version.raw_hex:
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pending.raw_tx_hex = version.raw_hex # empty only for a migration-reconstructed txid
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await _retarget_txid_references(session, pending, old_txid, txid)
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logger.warning("pending_transaction %s: version %s found on the network, replacing %s", pending.id, txid, old_txid)
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async def _retarget_txid_references(
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session: AsyncSession, pending: PendingTransaction, old_txid: str, new_txid: str
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) -> None:
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"""A bump changes the txid, and everything that recorded the old one has to
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follow — otherwise the bumped tx confirms and nothing recognizes it (B-02).
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The worst case was the bet path: _on_bet_confirmed used to look the participant
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up by bet_txid, so after a bump it found nothing, the participant stayed
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"broadcast" forever, and the scheduler waited on it forever — the round could
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never close and the lottery stopped. The handlers now key off immutable ids
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(round_id/user_id, withdrawal_id) as well, so this update is about keeping the
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stored txids *true* — for the admin UI, for the audit trail, and for
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reconcile.py, which matches UtxoEvent.spent_txid against current_txid.
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"""
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if pending.kind == "bet":
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participant = await session.scalar(
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select(RoundParticipant).where(
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RoundParticipant.round_id == pending.round_id,
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RoundParticipant.user_id == pending.user_id,
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)
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)
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if participant is not None:
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participant.bet_txid = new_txid
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elif pending.kind == "withdrawal" and pending.withdrawal_id is not None:
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withdrawal = await session.get(Withdrawal, pending.withdrawal_id)
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if withdrawal is not None:
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withdrawal.txid = new_txid
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elif pending.kind == "payout" and pending.round_id is not None:
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round_ = await session.get(Round, pending.round_id)
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if round_ is not None and round_.payout_txid == old_txid:
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round_.payout_txid = new_txid
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# The UTXOs this tx spends are still the same UTXOs — only the id of the tx
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# spending them changed. Keeping this in step is what lets reconcile.py tell
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# "reserved by this pending tx" from "spent by something else".
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spent = (await session.scalars(select(UtxoEvent).where(UtxoEvent.spent_txid == old_txid))).all()
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for utxo in spent:
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utxo.spent_txid = new_txid
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class RbfBumper:
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def __init__(self, session_factory: async_sessionmaker, get_client, network: TransactionNetwork | None = None):
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self._session_factory = session_factory
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self._get_client = get_client
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self._network = network # B-76/B-77: verifies and fans out a replacement
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async def run(self) -> None:
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while True:
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client = self._get_client()
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if client is not None:
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try:
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await self._tick(client)
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except asyncio.CancelledError:
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raise
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except Exception:
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logger.exception("RBF bump tick failed")
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await asyncio.sleep(_POLL_INTERVAL_SECONDS)
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async def _tick(self, client: ElectrumClient) -> None:
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now = datetime.now(timezone.utc)
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async with self._session_factory() as session:
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timeout_seconds = (await get_round_config(session)).rbf_timeout_seconds
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candidates = (
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await session.scalars(select(PendingTransaction).where(PendingTransaction.status == "pending"))
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).all()
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due_ids = [p.id for p in candidates if should_bump(p, now, timeout_seconds=timeout_seconds)]
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for pending_id in due_ids:
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try:
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await bump_fee(self._session_factory, client, pending_id, network=self._network)
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except RbfError:
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logger.exception("could not bump pending_transaction %s", pending_id)
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except Exception:
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logger.exception("unexpected error bumping pending_transaction %s", pending_id)
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