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wallet: Replace max descendant count with cluster_count
Public commit record
73/100 · Adequate
What the developer wrote
Authored by Suhas Daftuar
wallet: Replace max descendant count with cluster_count
With the descendant size limits removed, replace the concept of "max number of
descendants of any ancestor of a given tx" with the cluster count of the cluster
that the transaction belongs to.
✓ Specific, descriptive subject✓ Names a concrete action or component✓ Provides detailed explanatory context
What changed, and why it matters
This commit is a code cleanup in Bitcoin Core's transaction memory pool (mempool). It swaps one internal measurement—'maximum descendants'—for a newer equivalent called 'cluster count' after an older size limit was removed. The change is mostly renaming and updating tests to match; it does not appear to fix a security bug or introduce an obvious vulnerability.
Recommended action
No immediate action required. Treat as a normal refactor. If deploying, verify that wallet bump-fee/replace-by-fee logic relying on `getTransactionAncestry` tolerates the new cluster_count semantics, especially for diamond-shaped or merged transaction groups where cluster size can differ from the old per-ancestor descendant maximum.
Security signals we found
01
No security framing in commit message or diff
02
No bounds checks, memory allocations, or cryptographic operations changed
03
Behavioral change is limited to a single numeric return value used by wallet fee estimation
04
Unit tests updated to expect cluster size instead of per-transaction descendant maximum
Evidence from the diff
The patch renames the descendants output of CTxMemPool::GetTransactionAncestry() to cluster_count and changes its computation from CalculateDescendantMaximum(it) to m_txgraph->GetCluster(*it, TxGraph::Level::MAIN).size(). The wallet-facing Chain::getTransactionAncestry interface and unit tests are updated accordingly. The commit message frames this as a follow-up to the removal of descendant size limits, replacing a now-obsolete metric with the cluster count of the transaction’s connected component in the mempool graph.
Changed components
src/txmempool.cppsrc/txmempool.hsrc/node/interfaces.cppsrc/test/mempool_tests.cppInspect captured patch +70 / −70
diff --git a/src/node/interfaces.cpp b/src/node/interfaces.cpp
index c3e57291..65997267 100644
--- a/src/node/interfaces.cpp
+++ b/src/node/interfaces.cpp
@@ -678,11 +678,11 @@ public:
// that Chain clients do not need to know about.
return TransactionError::OK == err;
}
- void getTransactionAncestry(const Txid& txid, size_t& ancestors, size_t& descendants, size_t* ancestorsize, CAmount* ancestorfees) override
+ void getTransactionAncestry(const Txid& txid, size_t& ancestors, size_t& cluster_count, size_t* ancestorsize, CAmount* ancestorfees) override
{
- ancestors = descendants = 0;
+ ancestors = cluster_count = 0;
if (!m_node.mempool) return;
- m_node.mempool->GetTransactionAncestry(txid, ancestors, descendants, ancestorsize, ancestorfees);
+ m_node.mempool->GetTransactionAncestry(txid, ancestors, cluster_count, ancestorsize, ancestorfees);
}
std::map<COutPoint, CAmount> calculateIndividualBumpFees(const std::vector<COutPoint>& outpoints, const CFeeRate& target_feerate) override
diff --git a/src/test/mempool_tests.cpp b/src/test/mempool_tests.cpp
index 2271e7b8..d0cbdea7 100644
--- a/src/test/mempool_tests.cpp
+++ b/src/test/mempool_tests.cpp
@@ -296,7 +296,7 @@ inline CTransactionRef make_tx(std::vector<CAmount>&& output_values, std::vector
BOOST_AUTO_TEST_CASE(MempoolAncestryTests)
{
- size_t ancestors, descendants;
+ size_t ancestors, clustersize;
CTxMemPool& pool = *Assert(m_node.mempool);
LOCK2(cs_main, pool.cs);
@@ -309,10 +309,10 @@ BOOST_AUTO_TEST_CASE(MempoolAncestryTests)
CTransactionRef tx1 = make_tx(/*output_values=*/{10 * COIN});
AddToMempool(pool, entry.Fee(10000LL).FromTx(tx1));
- // Ancestors / descendants should be 1 / 1 (itself / itself)
- pool.GetTransactionAncestry(tx1->GetHash(), ancestors, descendants);
+ // Ancestors / clustersize should be 1 / 1 (itself / itself)
+ pool.GetTransactionAncestry(tx1->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 1ULL);
- BOOST_CHECK_EQUAL(descendants, 1ULL);
+ BOOST_CHECK_EQUAL(clustersize, 1ULL);
/* Child transaction */
//
@@ -321,17 +321,17 @@ BOOST_AUTO_TEST_CASE(MempoolAncestryTests)
CTransactionRef tx2 = make_tx(/*output_values=*/{495 * CENT, 5 * COIN}, /*inputs=*/{tx1});
AddToMempool(pool, entry.Fee(10000LL).FromTx(tx2));
- // Ancestors / descendants should be:
- // transaction ancestors descendants
+ // Ancestors / clustersize should be:
+ // transaction ancestors clustersize
// ============ =========== ===========
// tx1 1 (tx1) 2 (tx1,2)
// tx2 2 (tx1,2) 2 (tx1,2)
- pool.GetTransactionAncestry(tx1->GetHash(), ancestors, descendants);
+ pool.GetTransactionAncestry(tx1->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 1ULL);
- BOOST_CHECK_EQUAL(descendants, 2ULL);
- pool.GetTransactionAncestry(tx2->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 2ULL);
+ pool.GetTransactionAncestry(tx2->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 2ULL);
- BOOST_CHECK_EQUAL(descendants, 2ULL);
+ BOOST_CHECK_EQUAL(clustersize, 2ULL);
/* Grand-child 1 */
//
@@ -340,21 +340,21 @@ BOOST_AUTO_TEST_CASE(MempoolAncestryTests)
CTransactionRef tx3 = make_tx(/*output_values=*/{290 * CENT, 200 * CENT}, /*inputs=*/{tx2});
AddToMempool(pool, entry.Fee(10000LL).FromTx(tx3));
- // Ancestors / descendants should be:
- // transaction ancestors descendants
+ // Ancestors / clustersize should be:
+ // transaction ancestors clustersize
// ============ =========== ===========
// tx1 1 (tx1) 3 (tx1,2,3)
// tx2 2 (tx1,2) 3 (tx1,2,3)
// tx3 3 (tx1,2,3) 3 (tx1,2,3)
- pool.GetTransactionAncestry(tx1->GetHash(), ancestors, descendants);
+ pool.GetTransactionAncestry(tx1->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 1ULL);
- BOOST_CHECK_EQUAL(descendants, 3ULL);
- pool.GetTransactionAncestry(tx2->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 3ULL);
+ pool.GetTransactionAncestry(tx2->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 2ULL);
- BOOST_CHECK_EQUAL(descendants, 3ULL);
- pool.GetTransactionAncestry(tx3->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 3ULL);
+ pool.GetTransactionAncestry(tx3->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 3ULL);
- BOOST_CHECK_EQUAL(descendants, 3ULL);
+ BOOST_CHECK_EQUAL(clustersize, 3ULL);
/* Grand-child 2 */
//
@@ -365,25 +365,25 @@ BOOST_AUTO_TEST_CASE(MempoolAncestryTests)
CTransactionRef tx4 = make_tx(/*output_values=*/{290 * CENT, 250 * CENT}, /*inputs=*/{tx2}, /*input_indices=*/{1});
AddToMempool(pool, entry.Fee(10000LL).FromTx(tx4));
- // Ancestors / descendants should be:
- // transaction ancestors descendants
+ // Ancestors / clustersize should be:
+ // transaction ancestors clustersize
// ============ =========== ===========
// tx1 1 (tx1) 4 (tx1,2,3,4)
// tx2 2 (tx1,2) 4 (tx1,2,3,4)
// tx3 3 (tx1,2,3) 4 (tx1,2,3,4)
// tx4 3 (tx1,2,4) 4 (tx1,2,3,4)
- pool.GetTransactionAncestry(tx1->GetHash(), ancestors, descendants);
+ pool.GetTransactionAncestry(tx1->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 1ULL);
- BOOST_CHECK_EQUAL(descendants, 4ULL);
- pool.GetTransactionAncestry(tx2->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 4ULL);
+ pool.GetTransactionAncestry(tx2->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 2ULL);
- BOOST_CHECK_EQUAL(descendants, 4ULL);
- pool.GetTransactionAncestry(tx3->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 4ULL);
+ pool.GetTransactionAncestry(tx3->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 3ULL);
- BOOST_CHECK_EQUAL(descendants, 4ULL);
- pool.GetTransactionAncestry(tx4->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 4ULL);
+ pool.GetTransactionAncestry(tx4->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 3ULL);
- BOOST_CHECK_EQUAL(descendants, 4ULL);
+ BOOST_CHECK_EQUAL(clustersize, 4ULL);
/* Make an alternate branch that is longer and connect it to tx3 */
//
@@ -401,56 +401,56 @@ BOOST_AUTO_TEST_CASE(MempoolAncestryTests)
tyi = make_tx(/*output_values=*/{v}, /*inputs=*/i > 0 ? std::vector<CTransactionRef>{*ty[i - 1]} : std::vector<CTransactionRef>{});
v -= 50 * CENT;
AddToMempool(pool, entry.Fee(10000LL).FromTx(tyi));
- pool.GetTransactionAncestry(tyi->GetHash(), ancestors, descendants);
+ pool.GetTransactionAncestry(tyi->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, i+1);
- BOOST_CHECK_EQUAL(descendants, i+1);
+ BOOST_CHECK_EQUAL(clustersize, i+1);
}
CTransactionRef ty6 = make_tx(/*output_values=*/{5 * COIN}, /*inputs=*/{tx3, ty5});
AddToMempool(pool, entry.Fee(10000LL).FromTx(ty6));
- // Ancestors / descendants should be:
- // transaction ancestors descendants
+ // Ancestors / clustersize should be:
+ // transaction ancestors clustersize
// ============ =================== ===========
- // tx1 1 (tx1) 5 (tx1,2,3,4, ty6)
- // tx2 2 (tx1,2) 5 (tx1,2,3,4, ty6)
- // tx3 3 (tx1,2,3) 5 (tx1,2,3,4, ty6)
- // tx4 3 (tx1,2,4) 5 (tx1,2,3,4, ty6)
- // ty1 1 (ty1) 6 (ty1,2,3,4,5,6)
- // ty2 2 (ty1,2) 6 (ty1,2,3,4,5,6)
- // ty3 3 (ty1,2,3) 6 (ty1,2,3,4,5,6)
- // ty4 4 (y1234) 6 (ty1,2,3,4,5,6)
- // ty5 5 (y12345) 6 (ty1,2,3,4,5,6)
- // ty6 9 (tx123, ty123456) 6 (ty1,2,3,4,5,6)
- pool.GetTransactionAncestry(tx1->GetHash(), ancestors, descendants);
+ // tx1 1 (tx1) 10 (tx1-5, ty1-5)
+ // tx2 2 (tx1,2) 10
+ // tx3 3 (tx1,2,3) 10
+ // tx4 3 (tx1,2,4) 10
+ // ty1 1 (ty1) 10
+ // ty2 2 (ty1,2) 10
+ // ty3 3 (ty1,2,3) 10
+ // ty4 4 (y1234) 10
+ // ty5 5 (y12345) 10
+ // ty6 9 (tx123, ty123456) 10
+ pool.GetTransactionAncestry(tx1->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 1ULL);
- BOOST_CHECK_EQUAL(descendants, 5ULL);
- pool.GetTransactionAncestry(tx2->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 10ULL);
+ pool.GetTransactionAncestry(tx2->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 2ULL);
- BOOST_CHECK_EQUAL(descendants, 5ULL);
- pool.GetTransactionAncestry(tx3->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 10ULL);
+ pool.GetTransactionAncestry(tx3->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 3ULL);
- BOOST_CHECK_EQUAL(descendants, 5ULL);
- pool.GetTransactionAncestry(tx4->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 10ULL);
+ pool.GetTransactionAncestry(tx4->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 3ULL);
- BOOST_CHECK_EQUAL(descendants, 5ULL);
- pool.GetTransactionAncestry(ty1->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 10ULL);
+ pool.GetTransactionAncestry(ty1->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 1ULL);
- BOOST_CHECK_EQUAL(descendants, 6ULL);
- pool.GetTransactionAncestry(ty2->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 10ULL);
+ pool.GetTransactionAncestry(ty2->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 2ULL);
- BOOST_CHECK_EQUAL(descendants, 6ULL);
- pool.GetTransactionAncestry(ty3->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 10ULL);
+ pool.GetTransactionAncestry(ty3->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 3ULL);
- BOOST_CHECK_EQUAL(descendants, 6ULL);
- pool.GetTransactionAncestry(ty4->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 10ULL);
+ pool.GetTransactionAncestry(ty4->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 4ULL);
- BOOST_CHECK_EQUAL(descendants, 6ULL);
- pool.GetTransactionAncestry(ty5->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 10ULL);
+ pool.GetTransactionAncestry(ty5->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 5ULL);
- BOOST_CHECK_EQUAL(descendants, 6ULL);
- pool.GetTransactionAncestry(ty6->GetHash(), ancestors, descendants);
+ BOOST_CHECK_EQUAL(clustersize, 10ULL);
+ pool.GetTransactionAncestry(ty6->GetHash(), ancestors, clustersize);
BOOST_CHECK_EQUAL(ancestors, 9ULL);
- BOOST_CHECK_EQUAL(descendants, 6ULL);
+ BOOST_CHECK_EQUAL(clustersize, 10ULL);
}
BOOST_AUTO_TEST_CASE(MempoolAncestryTestsDiamond)
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index ab6d3ed2..e268fd61 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -1217,16 +1217,16 @@ std::tuple<size_t, size_t, CAmount> CTxMemPool::CalculateDescendantData(const CT
return {descendant_count, descendant_size, descendant_fees};
}
-void CTxMemPool::GetTransactionAncestry(const Txid& txid, size_t& ancestors, size_t& descendants, size_t* const ancestorsize, CAmount* const ancestorfees) const {
+void CTxMemPool::GetTransactionAncestry(const Txid& txid, size_t& ancestors, size_t& cluster_count, size_t* const ancestorsize, CAmount* const ancestorfees) const {
LOCK(cs);
auto it = mapTx.find(txid);
- ancestors = descendants = 0;
+ ancestors = cluster_count = 0;
if (it != mapTx.end()) {
auto [ancestor_count, ancestor_size, ancestor_fees] = CalculateAncestorData(*it);
- descendants = CalculateDescendantMaximum(it);
ancestors = ancestor_count;
if (ancestorsize) *ancestorsize = ancestor_size;
if (ancestorfees) *ancestorfees = ancestor_fees;
+ cluster_count = m_txgraph->GetCluster(*it, TxGraph::Level::MAIN).size();
}
}
diff --git a/src/txmempool.h b/src/txmempool.h
index 49ee510a..520410b6 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -516,12 +516,12 @@ public:
int Expire(std::chrono::seconds time) EXCLUSIVE_LOCKS_REQUIRED(cs);
/**
- * Calculate the ancestor and descendant count for the given transaction.
+ * Calculate the ancestor and cluster count for the given transaction.
* The counts include the transaction itself.
* When ancestors is non-zero (ie, the transaction itself is in the mempool),
* ancestorsize and ancestorfees will also be set to the appropriate values.
*/
- void GetTransactionAncestry(const Txid& txid, size_t& ancestors, size_t& descendants, size_t* ancestorsize = nullptr, CAmount* ancestorfees = nullptr) const;
+ void GetTransactionAncestry(const Txid& txid, size_t& ancestors, size_t& cluster_count, size_t* ancestorsize = nullptr, CAmount* ancestorfees = nullptr) const;
/**
* @returns true if an initial attempt to load the persisted mempool was made, regardless of
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