diff options
Diffstat (limited to 'src/validation.cpp')
| -rw-r--r-- | src/validation.cpp | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/src/validation.cpp b/src/validation.cpp index 2813b62462..86d0022947 100644 --- a/src/validation.cpp +++ b/src/validation.cpp @@ -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))) { |