wallet/rpc: add maxfeerate parameter to testmempoolaccept

Author: kallewoof

src/rpc/client.cpp

@@ -95,6 +95,7 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "sendrawtransaction", 1, "maxfeerate" },
     { "testmempoolaccept", 0, "rawtxs" },
     { "testmempoolaccept", 1, "allowhighfees" },
+    { "testmempoolaccept", 1, "maxfeerate" },
     { "combinerawtransaction", 0, "txs" },
     { "fundrawtransaction", 1, "options" },
     { "fundrawtransaction", 2, "iswitness" },

src/rpc/rawtransaction.cpp

@@ -1108,7 +1108,7 @@ static UniValue testmempoolaccept(const JSONRPCRequest& request)
                             {"rawtx", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED, ""},
                         },
                         },
-                    {"allowhighfees", RPCArg::Type::BOOL, /* default */ "false", "Allow high fees"},
+                    {"maxfeerate", RPCArg::Type::AMOUNT, /* default */ FormatMoney(maxTxFee), "Reject transactions whose fee rate is higher than the specified value, expressed in " + CURRENCY_UNIT + "/kB\n"},
                 },
                 RPCResult{
             "[                   (array) The result of the mempool acceptance test for each raw transaction in the input array.\n"
@@ -1133,7 +1133,11 @@ static UniValue testmempoolaccept(const JSONRPCRequest& request)
             }.ToString());
     }
 
-    RPCTypeCheck(request.params, {UniValue::VARR, UniValue::VBOOL});
+    RPCTypeCheck(request.params, {
+        UniValue::VARR,
+        UniValueType(), // NUM or BOOL, checked later
+    });
+
     if (request.params[0].get_array().size() != 1) {
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Array must contain exactly one raw transaction for now");
     }
@@ -1145,9 +1149,19 @@ static UniValue testmempoolaccept(const JSONRPCRequest& request)
     CTransactionRef tx(MakeTransactionRef(std::move(mtx)));
     const uint256& tx_hash = tx->GetHash();
 
-    CAmount max_raw_tx_fee = ::maxTxFee;
-    if (!request.params[1].isNull() && request.params[1].get_bool()) {
-        max_raw_tx_fee = 0;
+    CAmount max_raw_tx_fee = maxTxFee;
+    // TODO: temporary migration code for old clients. Remove in v0.20
+    if (request.params[1].isBool()) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Second argument must be numeric (maxfeerate) and no longer supports a boolean. To allow a transaction with high fees, set maxfeerate to 0.");
+    } else if (request.params[1].isNum()) {
+        size_t weight = GetTransactionWeight(*tx);
+        CFeeRate fr(AmountFromValue(request.params[1]));
+        // the +3/4 part rounds the value up, and is the same formula used when
+        // calculating the fee for a transaction
+        // (see GetVirtualTransactionSize)
+        max_raw_tx_fee = fr.GetFee((weight+3)/4);
+    } else if (!request.params[1].isNull()) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "second argument (maxfeerate) must be numeric");
     }
 
     UniValue result(UniValue::VARR);
@@ -2068,7 +2082,7 @@ static const CRPCCommand commands[] =
     { "rawtransactions",    "combinerawtransaction",        &combinerawtransaction,     {"txs"} },
     { "hidden",             "signrawtransaction",           &signrawtransaction,        {"hexstring","prevtxs","privkeys","sighashtype"} },
     { "rawtransactions",    "signrawtransactionwithkey",    &signrawtransactionwithkey, {"hexstring","privkeys","prevtxs","sighashtype"} },
-    { "rawtransactions",    "testmempoolaccept",            &testmempoolaccept,         {"rawtxs","allowhighfees"} },
+    { "rawtransactions",    "testmempoolaccept",            &testmempoolaccept,         {"rawtxs","allowhighfees|maxfeerate"} },
     { "rawtransactions",    "decodepsbt",                   &decodepsbt,                {"psbt"} },
     { "rawtransactions",    "combinepsbt",                  &combinepsbt,               {"txs"} },
     { "rawtransactions",    "finalizepsbt",                 &finalizepsbt,              {"psbt", "extract"} },

test/functional/feature_cltv.py

@@ -113,7 +113,7 @@ def run_test(self):
         # rejected from the mempool for exactly that reason.
         assert_equal(
             [{'txid': spendtx.hash, 'allowed': False, 'reject-reason': '64: non-mandatory-script-verify-flag (Negative locktime)'}],
-            self.nodes[0].testmempoolaccept(rawtxs=[spendtx.serialize().hex()], allowhighfees=True)
+            self.nodes[0].testmempoolaccept(rawtxs=[spendtx.serialize().hex()], maxfeerate=0)
         )
 
         # Now we verify that a block with this transaction is also invalid.

test/functional/feature_dersig.py

@@ -102,7 +102,7 @@ def run_test(self):
         # rejected from the mempool for exactly that reason.
         assert_equal(
             [{'txid': spendtx.hash, 'allowed': False, 'reject-reason': '64: non-mandatory-script-verify-flag (Non-canonical DER signature)'}],
-            self.nodes[0].testmempoolaccept(rawtxs=[spendtx.serialize().hex()], allowhighfees=True)
+            self.nodes[0].testmempoolaccept(rawtxs=[spendtx.serialize().hex()], maxfeerate=0)
         )
 
         # Now we verify that a block with this transaction is also invalid.

test/functional/rpc_rawtransaction.py

@@ -426,7 +426,7 @@ def run_test(self):
         decrawtx = self.nodes[0].decoderawtransaction(rawtx)
         assert_equal(decrawtx['version'], 0x7fffffff)
 
-        self.log.info('sendrawtransaction with maxfeerate')
+        self.log.info('sendrawtransaction/testmempoolaccept with maxfeerate')
 
         txId = self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(), 1.0)
         rawTx = self.nodes[0].getrawtransaction(txId, True)
@@ -439,9 +439,15 @@ def run_test(self):
         rawTxSigned = self.nodes[2].signrawtransactionwithwallet(rawTx)
         assert_equal(rawTxSigned['complete'], True)
         # 1000 sat fee, ~200 b transaction, fee rate should land around 5 sat/b = 0.00005000 BTC/kB
-        # Thus, below call should fail
+        # Thus, testmempoolaccept should reject
+        testres = self.nodes[2].testmempoolaccept([rawTxSigned['hex']], 0.00001000)[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'], 0.00001000)
-        # And below call should succeed
+        # And below calls should both succeed
+        testres = self.nodes[2].testmempoolaccept(rawtxs=[rawTxSigned['hex']], maxfeerate=0.00007000)[0]
+        assert_equal(testres['allowed'], True)
         self.nodes[2].sendrawtransaction(hexstring=rawTxSigned['hex'], maxfeerate=0.00007000)