Bugfix: Use pre-BIP141 sigops until segwit activates

qa/rpc-tests/segwit: Test GBT sigops before and after activation

Github-Pull: #8489
Rebased-From: 160f895a80 239cbd2e5c

qa/rpc-tests/segwit.py

@@ -69,6 +69,11 @@ def getutxo(txid):
     utxo["txid"] = txid
     return utxo
 
+def find_unspent(node, min_value):
+    for utxo in node.listunspent():
+        if utxo['amount'] >= min_value:
+            return utxo
+
 class SegWitTest(BitcoinTestFramework):
 
     def setup_chain(self):
@@ -117,8 +122,21 @@ class SegWitTest(BitcoinTestFramework):
         sync_blocks(self.nodes)
 
     def run_test(self):
-        self.nodes[0].generate(160) #block 160
-
+        self.nodes[0].generate(161) #block 161
+
+        print("Verify sigops are counted in GBT with pre-BIP141 rules before the fork")
+        txid = self.nodes[0].sendtoaddress(self.nodes[0].getnewaddress(), 1)
+        tmpl = self.nodes[0].getblocktemplate({})
+        assert(tmpl['sigoplimit'] == 20000)
+        assert(tmpl['transactions'][0]['hash'] == txid)
+        assert(tmpl['transactions'][0]['sigops'] == 2)
+        tmpl = self.nodes[0].getblocktemplate({'rules':['segwit']})
+        assert(tmpl['sigoplimit'] == 20000)
+        assert(tmpl['transactions'][0]['hash'] == txid)
+        assert(tmpl['transactions'][0]['sigops'] == 2)
+        self.nodes[0].generate(1) #block 162
+
+        balance_presetup = self.nodes[0].getbalance()
         self.pubkey = []
         p2sh_ids = [] # p2sh_ids[NODE][VER] is an array of txids that spend to a witness version VER pkscript to an address for NODE embedded in p2sh
         wit_ids = [] # wit_ids[NODE][VER] is an array of txids that spend to a witness version VER pkscript to an address for NODE via bare witness
@@ -137,18 +155,18 @@ class SegWitTest(BitcoinTestFramework):
         for i in range(5):
             for n in range(3):
                 for v in range(2):
-                    wit_ids[n][v].append(send_to_witness(v, self.nodes[0], self.nodes[0].listunspent()[0], self.pubkey[n], False, Decimal("49.999")))
-                    p2sh_ids[n][v].append(send_to_witness(v, self.nodes[0], self.nodes[0].listunspent()[0], self.pubkey[n], True, Decimal("49.999")))
+                    wit_ids[n][v].append(send_to_witness(v, self.nodes[0], find_unspent(self.nodes[0], 50), self.pubkey[n], False, Decimal("49.999")))
+                    p2sh_ids[n][v].append(send_to_witness(v, self.nodes[0], find_unspent(self.nodes[0], 50), self.pubkey[n], True, Decimal("49.999")))
 
-        self.nodes[0].generate(1) #block 161
+        self.nodes[0].generate(1) #block 163
         sync_blocks(self.nodes)
 
         # Make sure all nodes recognize the transactions as theirs
-        assert_equal(self.nodes[0].getbalance(), 60*50 - 60*50 + 20*Decimal("49.999") + 50)
+        assert_equal(self.nodes[0].getbalance(), balance_presetup - 60*50 + 20*Decimal("49.999") + 50)
         assert_equal(self.nodes[1].getbalance(), 20*Decimal("49.999"))
         assert_equal(self.nodes[2].getbalance(), 20*Decimal("49.999"))
 
-        self.nodes[0].generate(262) #block 423
+        self.nodes[0].generate(260) #block 423
         sync_blocks(self.nodes)
 
         print("Verify default node can't accept any witness format txs before fork")
@@ -205,5 +223,25 @@ class SegWitTest(BitcoinTestFramework):
         self.success_mine(self.nodes[0], p2sh_ids[NODE_0][WIT_V0][0], True) #block 434
         self.success_mine(self.nodes[0], p2sh_ids[NODE_0][WIT_V1][0], True) #block 435
 
+        print("Verify sigops are counted in GBT with BIP141 rules after the fork")
+        txid = self.nodes[0].sendtoaddress(self.nodes[0].getnewaddress(), 1)
+        tmpl = self.nodes[0].getblocktemplate({'rules':['segwit']})
+        assert(tmpl['sigoplimit'] == 80000)
+        assert(tmpl['transactions'][0]['txid'] == txid)
+        assert(tmpl['transactions'][0]['sigops'] == 8)
+
+        print("Verify non-segwit miners get a valid GBT response after the fork")
+        send_to_witness(1, self.nodes[0], find_unspent(self.nodes[0], 50), self.pubkey[0], False, Decimal("49.998"))
+        try:
+            tmpl = self.nodes[0].getblocktemplate({})
+            assert(len(tmpl['transactions']) == 1)  # Doesn't include witness tx
+            assert(tmpl['sigoplimit'] == 20000)
+            assert(tmpl['transactions'][0]['hash'] == txid)
+            assert(tmpl['transactions'][0]['sigops'] == 2)
+            assert(('!segwit' in tmpl['rules']) or ('segwit' not in tmpl['rules']))
+        except JSONRPCException:
+            # This is an acceptable outcome
+            pass
+
 if __name__ == '__main__':
     SegWitTest().main()

src/rpc/mining.cpp

@@ -546,6 +546,9 @@ UniValue getblocktemplate(const UniValue& params, bool fHelp)
     UpdateTime(pblock, consensusParams, pindexPrev);
     pblock->nNonce = 0;
 
+    // NOTE: If at some point we support pre-segwit miners post-segwit-activation, this needs to take segwit support into consideration
+    const bool fPreSegWit = (THRESHOLD_ACTIVE != VersionBitsState(pindexPrev, consensusParams, Consensus::DEPLOYMENT_SEGWIT, versionbitscache));
+
     UniValue aCaps(UniValue::VARR); aCaps.push_back("proposal");
 
     UniValue transactions(UniValue::VARR);
@@ -574,7 +577,12 @@ UniValue getblocktemplate(const UniValue& params, bool fHelp)
 
         int index_in_template = i - 1;
         entry.push_back(Pair("fee", pblocktemplate->vTxFees[index_in_template]));
-        entry.push_back(Pair("sigops", pblocktemplate->vTxSigOpsCost[index_in_template]));
+        int64_t nTxSigOps = pblocktemplate->vTxSigOpsCost[index_in_template];
+        if (fPreSegWit) {
+            assert(nTxSigOps % WITNESS_SCALE_FACTOR == 0);
+            nTxSigOps /= WITNESS_SCALE_FACTOR;
+        }
+        entry.push_back(Pair("sigops", nTxSigOps));
         entry.push_back(Pair("weight", GetTransactionWeight(tx)));
 
         transactions.push_back(entry);
@@ -657,7 +665,12 @@ UniValue getblocktemplate(const UniValue& params, bool fHelp)
     result.push_back(Pair("mintime", (int64_t)pindexPrev->GetMedianTimePast()+1));
     result.push_back(Pair("mutable", aMutable));
     result.push_back(Pair("noncerange", "00000000ffffffff"));
-    result.push_back(Pair("sigoplimit", (int64_t)MAX_BLOCK_SIGOPS_COST));
+    int64_t nSigOpLimit = MAX_BLOCK_SIGOPS_COST;
+    if (fPreSegWit) {
+        assert(nSigOpLimit % WITNESS_SCALE_FACTOR == 0);
+        nSigOpLimit /= WITNESS_SCALE_FACTOR;
+    }
+    result.push_back(Pair("sigoplimit", nSigOpLimit));
     result.push_back(Pair("sizelimit", (int64_t)MAX_BLOCK_SERIALIZED_SIZE));
     result.push_back(Pair("weightlimit", (int64_t)MAX_BLOCK_WEIGHT));
     result.push_back(Pair("curtime", pblock->GetBlockTime()));