Merge #16521: rpc: Use the default maxfeerate value as BTC/kB

2dfd6834ef8737e16e4b96df0c459f30a0721d6c test: Add test for default maxfeerate in sendrawtransaction (Joonmo Yang)
261843e4bef96ab296a9775819a99bfa60cad743 wallet/rpc: Use the default maxfeerate value as BTC/kB (Joonmo Yang)

Pull request description:

  Fixes https://github.com/bitcoin/bitcoin/issues/16382

  This patch tries to treat `maxfeerate` in sendrawtransaction/testmempoolaccept RPC as a rate(BTC/kB) instead of an absolute value(BTC).
  The included test case checks if the new behavior works correctly, by using the transaction with an absolute fee of ~0.02BTC, where the fee rate is ~0.2BTC/kB.
  This test should be failing if the default `maxfeerate` is 0.1BTC, but pass if the default value is 0.1BTC/kB

ACKs for top commit:
  laanwj:
    ACK 2dfd6834ef8737e16e4b96df0c459f30a0721d6c (ACKs by Sjors and MarcoFalke above for trivially different code)

Tree-SHA512: a1795bffe8a182acef8844797955db1f60bb0c0ded97148f3572dc265234d5219271a3a7aa0b6418a43f73b2b2720ef7412ba169c99bb1cdcac52051f537d6af

4 files changed, 31 insertions, 6 deletions

diff --git a/test/functional/feature_segwit.py b/test/functional/feature_segwit.py
index b9db618575..d2826dd1b7 100755
--- a/test/functional/feature_segwit.py
+++ b/test/functional/feature_segwit.py
@@ -257,7 +257,7 @@ class SegWitTest(BitcoinTestFramework):
         tx.vin.append(CTxIn(COutPoint(int(txid2, 16), 0), b""))
         tx.vout.append(CTxOut(int(49.95 * COIN), CScript([OP_TRUE, OP_DROP] * 15 + [OP_TRUE])))  # Huge fee
         tx.calc_sha256()
-        txid3 = self.nodes[0].sendrawtransaction(ToHex(tx))
+        txid3 = self.nodes[0].sendrawtransaction(ToHex(tx), 0)
         assert tx.wit.is_null()
         assert txid3 in self.nodes[0].getrawmempool()
 
diff --git a/test/functional/mempool_accept.py b/test/functional/mempool_accept.py
index e19e249f21..dee7a04516 100755
--- a/test/functional/mempool_accept.py
+++ b/test/functional/mempool_accept.py
@@ -183,6 +183,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': True}],
             rawtxs=[tx.serialize().hex()],
+            maxfeerate=0,
         )
 
         self.log.info('A transaction with no outputs')
diff --git a/test/functional/rpc_rawtransaction.py b/test/functional/rpc_rawtransaction.py
index 4338675270..d1ce97efff 100755
--- a/test/functional/rpc_rawtransaction.py
+++ b/test/functional/rpc_rawtransaction.py
@@ -432,17 +432,18 @@ class RawTransactionsTest(BitcoinTestFramework):
 
         self.log.info('sendrawtransaction/testmempoolaccept with maxfeerate')
 
+        # Test a transaction with small fee
         txId = self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(), 1.0)
         rawTx = self.nodes[0].getrawtransaction(txId, True)
         vout = next(o for o in rawTx['vout'] if o['value'] == Decimal('1.00000000'))
 
         self.sync_all()
         inputs = [{ "txid" : txId, "vout" : vout['n'] }]
-        outputs = { self.nodes[0].getnewaddress() : Decimal("0.99999000") } # 1000 sat fee
+        outputs = { self.nodes[0].getnewaddress() : Decimal("0.999990000") } # 10000 sat fee
         rawTx = self.nodes[2].createrawtransaction(inputs, outputs)
         rawTxSigned = self.nodes[2].signrawtransactionwithwallet(rawTx)
         assert_equal(rawTxSigned['complete'], True)
-        # 1000 sat fee, ~100 b transaction, fee rate should land around 10 sat/b = 0.00010000 BTC/kB
+        # 10000 sat fee, ~100 b transaction, fee rate should land around 100 sat/b = 0.00100000 BTC/kB
         # Thus, testmempoolaccept should reject
         testres = self.nodes[2].testmempoolaccept([rawTxSigned['hex']], 0.00001000)[0]
         assert_equal(testres['allowed'], False)
@@ -450,9 +451,32 @@ class RawTransactionsTest(BitcoinTestFramework):
         # and sendrawtransaction should throw
         assert_raises_rpc_error(-26, "absurdly-high-fee", self.nodes[2].sendrawtransaction, rawTxSigned['hex'], 0.00001000)
         # And below calls should both succeed
-        testres = self.nodes[2].testmempoolaccept(rawtxs=[rawTxSigned['hex']], maxfeerate='0.00070000')[0]
+        testres = self.nodes[2].testmempoolaccept(rawtxs=[rawTxSigned['hex']])[0]
         assert_equal(testres['allowed'], True)
-        self.nodes[2].sendrawtransaction(hexstring=rawTxSigned['hex'], maxfeerate='0.00070000')
+        self.nodes[2].sendrawtransaction(hexstring=rawTxSigned['hex'])
+
+        # Test a transaction with large fee
+        txId = self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(), 1.0)
+        rawTx = self.nodes[0].getrawtransaction(txId, True)
+        vout = next(o for o in rawTx['vout'] if o['value'] == Decimal('1.00000000'))
+
+        self.sync_all()
+        inputs = [{ "txid" : txId, "vout" : vout['n'] }]
+        outputs = { self.nodes[0].getnewaddress() : Decimal("0.98000000") } # 2000000 sat fee
+        rawTx = self.nodes[2].createrawtransaction(inputs, outputs)
+        rawTxSigned = self.nodes[2].signrawtransactionwithwallet(rawTx)
+        assert_equal(rawTxSigned['complete'], True)
+        # 2000000 sat fee, ~100 b transaction, fee rate should land around 20000 sat/b = 0.20000000 BTC/kB
+        # Thus, testmempoolaccept should reject
+        testres = self.nodes[2].testmempoolaccept([rawTxSigned['hex']])[0]
+        assert_equal(testres['allowed'], False)
+        assert_equal(testres['reject-reason'], '256: absurdly-high-fee')
+        # and sendrawtransaction should throw
+        assert_raises_rpc_error(-26, "absurdly-high-fee", self.nodes[2].sendrawtransaction, rawTxSigned['hex'])
+        # And below calls should both succeed
+        testres = self.nodes[2].testmempoolaccept(rawtxs=[rawTxSigned['hex']], maxfeerate='0.20000000')[0]
+        assert_equal(testres['allowed'], True)
+        self.nodes[2].sendrawtransaction(hexstring=rawTxSigned['hex'], maxfeerate='0.20000000')
 
 
 if __name__ == '__main__':
diff --git a/test/functional/wallet_basic.py b/test/functional/wallet_basic.py
index ce04110240..2283bff2e6 100755
--- a/test/functional/wallet_basic.py
+++ b/test/functional/wallet_basic.py
@@ -433,7 +433,7 @@ class WalletTest(BitcoinTestFramework):
         # Split into two chains
         rawtx = self.nodes[0].createrawtransaction([{"txid": singletxid, "vout": 0}], {chain_addrs[0]: node0_balance / 2 - Decimal('0.01'), chain_addrs[1]: node0_balance / 2 - Decimal('0.01')})
         signedtx = self.nodes[0].signrawtransactionwithwallet(rawtx)
-        singletxid = self.nodes[0].sendrawtransaction(signedtx["hex"])
+        singletxid = self.nodes[0].sendrawtransaction(signedtx["hex"], 0)
         self.nodes[0].generate(1)
 
         # Make a long chain of unconfirmed payments without hitting mempool limit