Merge bitcoin/bitcoin#24310: docs / fixups from RBF and packages

77202f0554 [doc] package deduplication (glozow)
d35a3cb396 [doc] clarify inaccurate comment about replacements paying higher feerate (glozow)
5ae187f876 [validation] look up transaction by txid (glozow)

Pull request description:

  - Use txid, not wtxid, for `mempool.GetIter()`: https://github.com/bitcoin/bitcoin/pull/22674#discussion_r772934994
  - Fix a historically inaccurate comment about RBF during the refactors: https://github.com/bitcoin/bitcoin/pull/22855#discussion_r777130441
  - Add a section about package deduplication to policy/packages.md: https://github.com/bitcoin/bitcoin/pull/24152#discussion_r802955759 and https://github.com/bitcoin/bitcoin/pull/24152#discussion_r802723149

  (I'm intending for this to be in v23 since it's fixups for things that are already merged, which is why I split it from #24152)

ACKs for top commit:
  t-bast:
    LGTM, ACK 77202f0554
  darosior:
    ACK 77202f0554
  LarryRuane:
    ACK 77202f0554

Tree-SHA512: a428e791dfa59c359d3ccc67e8d3a4c1239815d2f6b29898e129700079271c00b3a45f091f70b65a6e54aa00a3d5b678b6da29d2a76b6cd6f946eaa7082ea696
This commit is contained in:
fanquake
2022-02-22 09:16:04 +00:00
3 changed files with 36 additions and 7 deletions

View File

@@ -915,12 +915,15 @@ bool MemPoolAccept::ReplacementChecks(Workspace& ws)
TxValidationState& state = ws.m_state;
CFeeRate newFeeRate(ws.m_modified_fees, ws.m_vsize);
// It's possible that the replacement pays more fees than its direct conflicts but not more
// than all conflicts (i.e. the direct conflicts have high-fee descendants). However, if the
// replacement doesn't pay more fees than its direct conflicts, then we can be sure it's not
// more economically rational to mine. Before we go digging through the mempool for all
// transactions that would need to be removed (direct conflicts and all descendants), check
// that the replacement transaction pays more than its direct conflicts.
// The replacement transaction must have a higher feerate than its direct conflicts.
// - The motivation for this check is to ensure that the replacement transaction is preferable for
// block-inclusion, compared to what would be removed from the mempool.
// - This logic predates ancestor feerate-based transaction selection, which is why it doesn't
// consider feerates of descendants.
// - Note: Ancestor feerate-based transaction selection has made this comparison insufficient to
// guarantee that this is incentive-compatible for miners, because it is possible for a
// descendant transaction of a direct conflict to pay a higher feerate than the transaction that
// might replace them, under these rules.
if (const auto err_string{PaysMoreThanConflicts(ws.m_iters_conflicting, newFeeRate, hash)}) {
return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "insufficient fee", *err_string);
}
@@ -1318,7 +1321,7 @@ PackageMempoolAcceptResult MemPoolAccept::AcceptPackage(const Package& package,
// we know is that the inputs aren't available.
if (m_pool.exists(GenTxid::Wtxid(wtxid))) {
// Exact transaction already exists in the mempool.
auto iter = m_pool.GetIter(wtxid);
auto iter = m_pool.GetIter(txid);
assert(iter != std::nullopt);
results.emplace(wtxid, MempoolAcceptResult::MempoolTx(iter.value()->GetTxSize(), iter.value()->GetFee()));
} else if (m_pool.exists(GenTxid::Txid(txid))) {