From 23fbbb100f63cb621b4b901dac0c0f16d7d74bc7 Mon Sep 17 00:00:00 2001
From: Karl-Johan Alm <kalle.alm@gmail.com>
Date: Tue, 31 Jul 2018 04:42:41 +0900
Subject: [PATCH] wallet: sum ancestors rather than taking max in output groups
---
src/wallet/coinselection.cpp | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/src/wallet/coinselection.cpp b/src/wallet/coinselection.cpp
index 1a810e763..710146ef9 100644
--- a/src/wallet/coinselection.cpp
+++ b/src/wallet/coinselection.cpp
@@ -299,12 +299,12 @@ void OutputGroup::Insert(const CInputCoin& output, int depth, bool from_me, size
m_from_me &= from_me;
m_value += output.effective_value;
m_depth = std::min(m_depth, depth);
- // m_ancestors is currently the max ancestor count for all coins in the group; however, this is
- // not ideal, as a wallet will consider e.g. thirty 2-ancestor coins as having two ancestors,
- // when in reality it has 60 ancestors.
- m_ancestors = std::max(m_ancestors, ancestors);
- // m_descendants is the count as seen from the top ancestor, not the descendants as seen from the
- // coin itself; thus, this value is accurate
+ // ancestors here express the number of ancestors the new coin will end up having, which is
+ // the sum, rather than the max; this will overestimate in the cases where multiple inputs
+ // have common ancestors
+ m_ancestors += ancestors;
+ // descendants is the count as seen from the top ancestor, not the descendants as seen from the
+ // coin itself; thus, this value is counted as the max, not the sum
m_descendants = std::max(m_descendants, descendants);
effective_value = m_value;
}