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policy: Remove CPFP carveout rule

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The addition of a cluster size limit makes the CPFP carveout rule useless,
because carveout cannot be used to bypass the cluster size limit. Remove this
policy rule and update tests to no longer rely on the behavior.
This commit is contained in:
Suhas Daftuar
2023-10-03 10:54:30 -04:00
parent c3f1afc934
commit ff8f115dec
4 changed files with 7 additions and 118 deletions
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35
src/validation.cpp
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@@ -1014,40 +1014,7 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
if (auto ancestors{m_subpackage.m_changeset->CalculateMemPoolAncestors(ws.m_tx_handle, maybe_rbf_limits)}) {
ws.m_ancestors = std::move(*ancestors);
} else {
// If CalculateMemPoolAncestors fails second time, we want the original error string.
const auto error_message{util::ErrorString(ancestors).original};
// Carve-out is not allowed in this context; fail
if (!args.m_allow_carveouts) {
return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "too-long-mempool-chain", error_message);
}
// Contracting/payment channels CPFP carve-out:
// If the new transaction is relatively small (up to 40k weight)
// and has at most one ancestor (ie ancestor limit of 2, including
// the new transaction), allow it if its parent has exactly the
// descendant limit descendants. The transaction also cannot be TRUC,
// as its topology restrictions do not allow a second child.
//
// This allows protocols which rely on distrusting counterparties
// being able to broadcast descendants of an unconfirmed transaction
// to be secure by simply only having two immediately-spendable
// outputs - one for each counterparty. For more info on the uses for
// this, see https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-November/016518.html
CTxMemPool::Limits cpfp_carve_out_limits{
.ancestor_count = 2,
.ancestor_size_vbytes = maybe_rbf_limits.ancestor_size_vbytes,
.descendant_count = maybe_rbf_limits.descendant_count + 1,
.descendant_size_vbytes = maybe_rbf_limits.descendant_size_vbytes + EXTRA_DESCENDANT_TX_SIZE_LIMIT,
};
if (ws.m_vsize > EXTRA_DESCENDANT_TX_SIZE_LIMIT || ws.m_ptx->version == TRUC_VERSION) {
return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "too-long-mempool-chain", error_message);
}
if (auto ancestors_retry{m_subpackage.m_changeset->CalculateMemPoolAncestors(ws.m_tx_handle, cpfp_carve_out_limits)}) {
ws.m_ancestors = std::move(*ancestors_retry);
} else {
return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "too-long-mempool-chain", error_message);
}
return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY, "too-long-mempool-chain", util::ErrorString(ancestors).original);
}
// Even though just checking direct mempool parents for inheritance would be sufficient, we