Update replace-by-fee logic to use fee deltas

qa/rpc-tests/replace-by-fee.py

@@ -63,8 +63,14 @@ def make_utxo(node, amount, confirmed=True, scriptPubKey=CScript([1])):
 
     # If requested, ensure txouts are confirmed.
     if confirmed:
-        while len(node.getrawmempool()):
+        mempool_size = len(node.getrawmempool())
+        while mempool_size > 0:
             node.generate(1)
+            new_size = len(node.getrawmempool())
+            # Error out if we have something stuck in the mempool, as this
+            # would likely be a bug.
+            assert(new_size < mempool_size)
+            mempool_size = new_size
 
     return COutPoint(int(txid, 16), 0)
 
@@ -72,7 +78,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
     def setup_network(self):
         self.nodes = []
-        self.nodes.append(start_node(0, self.options.tmpdir, ["-maxorphantx=1000",
+        self.nodes.append(start_node(0, self.options.tmpdir, ["-maxorphantx=1000", "-debug",
                                                               "-relaypriority=0", "-whitelist=127.0.0.1",
                                                               "-limitancestorcount=50",
                                                               "-limitancestorsize=101",
@@ -108,6 +114,9 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         print "Running test opt-in..."
         self.test_opt_in()
 
+        print "Running test prioritised transactions..."
+        self.test_prioritised_transactions()
+
         print "Passed\n"
 
     def test_simple_doublespend(self):
@@ -513,5 +522,72 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # but make sure it is accepted anyway
         self.nodes[0].sendrawtransaction(tx3c_hex, True)
 
+    def test_prioritised_transactions(self):
+        # Ensure that fee deltas used via prioritisetransaction are
+        # correctly used by replacement logic
+
+        # 1. Check that feeperkb uses modified fees
+        tx0_outpoint = make_utxo(self.nodes[0], 1.1*COIN)
+
+        tx1a = CTransaction()
+        tx1a.vin = [CTxIn(tx0_outpoint, nSequence=0)]
+        tx1a.vout = [CTxOut(1*COIN, CScript([b'a']))]
+        tx1a_hex = txToHex(tx1a)
+        tx1a_txid = self.nodes[0].sendrawtransaction(tx1a_hex, True)
+
+        # Higher fee, but the actual fee per KB is much lower.
+        tx1b = CTransaction()
+        tx1b.vin = [CTxIn(tx0_outpoint, nSequence=0)]
+        tx1b.vout = [CTxOut(0.001*COIN, CScript([b'a'*740000]))]
+        tx1b_hex = txToHex(tx1b)
+
+        # Verify tx1b cannot replace tx1a.
+        try:
+            tx1b_txid = self.nodes[0].sendrawtransaction(tx1b_hex, True)
+        except JSONRPCException as exp:
+            assert_equal(exp.error['code'], -26)
+        else:
+            assert(False)
+
+        # Use prioritisetransaction to set tx1a's fee to 0.
+        self.nodes[0].prioritisetransaction(tx1a_txid, 0, int(-0.1*COIN))
+
+        # Now tx1b should be able to replace tx1a
+        tx1b_txid = self.nodes[0].sendrawtransaction(tx1b_hex, True)
+
+        assert(tx1b_txid in self.nodes[0].getrawmempool())
+
+        # 2. Check that absolute fee checks use modified fee.
+        tx1_outpoint = make_utxo(self.nodes[0], 1.1*COIN)
+
+        tx2a = CTransaction()
+        tx2a.vin = [CTxIn(tx1_outpoint, nSequence=0)]
+        tx2a.vout = [CTxOut(1*COIN, CScript([b'a']))]
+        tx2a_hex = txToHex(tx2a)
+        tx2a_txid = self.nodes[0].sendrawtransaction(tx2a_hex, True)
+
+        # Lower fee, but we'll prioritise it
+        tx2b = CTransaction()
+        tx2b.vin = [CTxIn(tx1_outpoint, nSequence=0)]
+        tx2b.vout = [CTxOut(1.01*COIN, CScript([b'a']))]
+        tx2b.rehash()
+        tx2b_hex = txToHex(tx2b)
+
+        # Verify tx2b cannot replace tx2a.
+        try:
+            tx2b_txid = self.nodes[0].sendrawtransaction(tx2b_hex, True)
+        except JSONRPCException as exp:
+            assert_equal(exp.error['code'], -26)
+        else:
+            assert(False)
+
+        # Now prioritise tx2b to have a higher modified fee
+        self.nodes[0].prioritisetransaction(tx2b.hash, 0, int(0.1*COIN))
+
+        # tx2b should now be accepted
+        tx2b_txid = self.nodes[0].sendrawtransaction(tx2b_hex, True)
+
+        assert(tx2b_txid in self.nodes[0].getrawmempool())
+
 if __name__ == '__main__':
     ReplaceByFeeTest().main()

src/main.cpp

@@ -1061,13 +1061,17 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState &state, const C
         uint64_t nConflictingCount = 0;
         CTxMemPool::setEntries allConflicting;
 
+        CAmount nModifiedFees = nFees;
+        double nPriorityDummy = 0;
+        pool.ApplyDeltas(hash, nPriorityDummy, nModifiedFees);
+
         // If we don't hold the lock allConflicting might be incomplete; the
         // subsequent RemoveStaged() and addUnchecked() calls don't guarantee
         // mempool consistency for us.
         LOCK(pool.cs);
         if (setConflicts.size())
         {
-            CFeeRate newFeeRate(nFees, nSize);
+            CFeeRate newFeeRate(nModifiedFees, nSize);
             set<uint256> setConflictsParents;
             const int maxDescendantsToVisit = 100;
             CTxMemPool::setEntries setIterConflicting;
@@ -1110,7 +1114,7 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState &state, const C
                 // ignored when deciding whether or not to replace, we do
                 // require the replacement to pay more overall fees too,
                 // mitigating most cases.
-                CFeeRate oldFeeRate(mi->GetFee(), mi->GetTxSize());
+                CFeeRate oldFeeRate(mi->GetModifiedFee(), mi->GetTxSize());
                 if (newFeeRate <= oldFeeRate)
                 {
                     return state.DoS(0,
@@ -1138,7 +1142,7 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState &state, const C
                     pool.CalculateDescendants(it, allConflicting);
                 }
                 BOOST_FOREACH(CTxMemPool::txiter it, allConflicting) {
-                    nConflictingFees += it->GetFee();
+                    nConflictingFees += it->GetModifiedFee();
                     nConflictingSize += it->GetTxSize();
                 }
             } else {
@@ -1171,16 +1175,16 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState &state, const C
             // The replacement must pay greater fees than the transactions it
             // replaces - if we did the bandwidth used by those conflicting
             // transactions would not be paid for.
-            if (nFees < nConflictingFees)
+            if (nModifiedFees < nConflictingFees)
             {
                 return state.DoS(0, error("AcceptToMemoryPool: rejecting replacement %s, less fees than conflicting txs; %s < %s",
-                                          hash.ToString(), FormatMoney(nFees), FormatMoney(nConflictingFees)),
+                                          hash.ToString(), FormatMoney(nModifiedFees), FormatMoney(nConflictingFees)),
                                  REJECT_INSUFFICIENTFEE, "insufficient fee");
             }
 
             // Finally in addition to paying more fees than the conflicts the
             // new transaction must pay for its own bandwidth.
-            CAmount nDeltaFees = nFees - nConflictingFees;
+            CAmount nDeltaFees = nModifiedFees - nConflictingFees;
             if (nDeltaFees < ::minRelayTxFee.GetFee(nSize))
             {
                 return state.DoS(0,
@@ -1218,7 +1222,7 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState &state, const C
             LogPrint("mempool", "replacing tx %s with %s for %s BTC additional fees, %d delta bytes\n",
                     it->GetTx().GetHash().ToString(),
                     hash.ToString(),
-                    FormatMoney(nFees - nConflictingFees),
+                    FormatMoney(nModifiedFees - nConflictingFees),
                     (int)nSize - (int)nConflictingSize);
         }
         pool.RemoveStaged(allConflicting);