From b2b361926215eadd6bf43ed1d7110b925fc7cae5 Mon Sep 17 00:00:00 2001
From: Tom Harding <tomh@thinlink.com>
Date: Wed, 11 Mar 2015 16:48:53 -0700
Subject: [PATCH] Implement CTransaction::IsEquivalentTo(...)

Define CTransaction::IsEquivalentTo(const CTransaction& tx)

True if only scriptSigs are different.  In other words, true if
the two transactions are malleability clones.  In other words,
true if the two transactions have the same effect on the
outside universe.

In the wallet, only SyncMetaData for equivalent transactions.
---
 src/primitives/transaction.cpp | 9 +++++++++
 src/primitives/transaction.h   | 3 +++
 src/wallet/wallet.cpp          | 1 +
 3 files changed, 13 insertions(+)

diff --git a/src/primitives/transaction.cpp b/src/primitives/transaction.cpp
index 606dbea79..d864a9b6d 100644
--- a/src/primitives/transaction.cpp
+++ b/src/primitives/transaction.cpp
@@ -87,6 +87,15 @@ CTransaction& CTransaction::operator=(const CTransaction &tx) {
     return *this;
 }
 
+bool CTransaction::IsEquivalentTo(const CTransaction& tx) const
+{
+	CMutableTransaction tx1 = *this;
+	CMutableTransaction tx2 = tx;
+	for (unsigned int i = 0; i < tx1.vin.size(); i++) tx1.vin[i].scriptSig = CScript();
+	for (unsigned int i = 0; i < tx2.vin.size(); i++) tx2.vin[i].scriptSig = CScript();
+	return CTransaction(tx1) == CTransaction(tx2);
+}
+
 CAmount CTransaction::GetValueOut() const
 {
     CAmount nValueOut = 0;
diff --git a/src/primitives/transaction.h b/src/primitives/transaction.h
index 6cfd93a9a..0c9ebb7b8 100644
--- a/src/primitives/transaction.h
+++ b/src/primitives/transaction.h
@@ -222,6 +222,9 @@ public:
         return hash;
     }
 
+    // True if only scriptSigs are different
+    bool IsEquivalentTo(const CTransaction& tx) const;
+
     // Return sum of txouts.
     CAmount GetValueOut() const;
     // GetValueIn() is a method on CCoinsViewCache, because
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 2566b2712..92bb972cf 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -417,6 +417,7 @@ void CWallet::SyncMetaData(pair<TxSpends::iterator, TxSpends::iterator> range)
         const uint256& hash = it->second;
         CWalletTx* copyTo = &mapWallet[hash];
         if (copyFrom == copyTo) continue;
+        if (!copyFrom->IsEquivalentTo(*copyTo)) continue;
         copyTo->mapValue = copyFrom->mapValue;
         copyTo->vOrderForm = copyFrom->vOrderForm;
         // fTimeReceivedIsTxTime not copied on purpose