Merge bitcoin/bitcoin#25344: New outputs argument for bumpfee/psbtbumpfee

4c8eccc test: add tests for `outputs` argument to `bumpfee`/`psbtbumpfee` (Seibart Nedor)
c0ebb98 wallet: add `outputs` arguments to `bumpfee` and `psbtbumpfee` (Seibart Nedor)
a804f3c wallet: extract and reuse RPC argument format definition for outputs (Seibart Nedor)

Pull request description:

  This implements a modification of the proposal in #22007: instead of **adding** outputs to the set of outputs in the original transaction, the outputs given by `outputs` argument **completely replace** the outputs in the original transaction.

  As noted below, this makes it easier to "cancel" a transaction or to reduce the amounts in the outputs, which is not the case with the original proposal in #22007, but it seems from the discussion in this PR that the **replace** behavior is more desirable than **add** one.

ACKs for top commit:
  achow101:
    ACK 4c8eccc
  1440000bytes:
    Code Review ACK bitcoin/bitcoin@4c8eccc
  ishaanam:
    reACK 4c8eccc

Tree-SHA512: 31361f4a9b79c162bda7929583b0a3fd200e09f4c1a5378b12007576d6b14e02e9e4f0bab8aa209f08f75ac25a1f4805ad16ebff4a0334b07ad2378cc0090103

Author: achow101

src/rpc/rawtransaction_util.cpp

@@ -21,31 +21,15 @@
 #include <util/strencodings.h>
 #include <util/translation.h>
 
-CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, std::optional<bool> rbf)
+void AddInputs(CMutableTransaction& rawTx, const UniValue& inputs_in, std::optional<bool> rbf)
 {
-    if (outputs_in.isNull()) {
-        throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, output argument must be non-null");
-    }
-
     UniValue inputs;
     if (inputs_in.isNull()) {
         inputs = UniValue::VARR;
     } else {
         inputs = inputs_in.get_array();
     }
 
-    const bool outputs_is_obj = outputs_in.isObject();
-    UniValue outputs = outputs_is_obj ? outputs_in.get_obj() : outputs_in.get_array();
-
-    CMutableTransaction rawTx;
-
-    if (!locktime.isNull()) {
-        int64_t nLockTime = locktime.getInt<int64_t>();
-        if (nLockTime < 0 || nLockTime > LOCKTIME_MAX)
-            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, locktime out of range");
-        rawTx.nLockTime = nLockTime;
-    }
-
     for (unsigned int idx = 0; idx < inputs.size(); idx++) {
         const UniValue& input = inputs[idx];
         const UniValue& o = input.get_obj();
@@ -84,6 +68,16 @@ CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniVal
 
         rawTx.vin.push_back(in);
     }
+}
+
+void AddOutputs(CMutableTransaction& rawTx, const UniValue& outputs_in)
+{
+    if (outputs_in.isNull()) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, output argument must be non-null");
+    }
+
+    const bool outputs_is_obj = outputs_in.isObject();
+    UniValue outputs = outputs_is_obj ? outputs_in.get_obj() : outputs_in.get_array();
 
     if (!outputs_is_obj) {
         // Translate array of key-value pairs into dict
@@ -132,6 +126,21 @@ CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniVal
             rawTx.vout.push_back(out);
         }
     }
+}
+
+CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, std::optional<bool> rbf)
+{
+    CMutableTransaction rawTx;
+
+    if (!locktime.isNull()) {
+        int64_t nLockTime = locktime.getInt<int64_t>();
+        if (nLockTime < 0 || nLockTime > LOCKTIME_MAX)
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, locktime out of range");
+        rawTx.nLockTime = nLockTime;
+    }
+
+    AddInputs(rawTx, inputs_in, rbf);
+    AddOutputs(rawTx, outputs_in);
 
     if (rbf.has_value() && rbf.value() && rawTx.vin.size() > 0 && !SignalsOptInRBF(CTransaction(rawTx))) {
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter combination: Sequence number(s) contradict replaceable option");

src/rpc/rawtransaction_util.h

@@ -38,6 +38,13 @@ void SignTransactionResultToJSON(CMutableTransaction& mtx, bool complete, const
   */
 void ParsePrevouts(const UniValue& prevTxsUnival, FillableSigningProvider* keystore, std::map<COutPoint, Coin>& coins);
 
+
+/** Normalize univalue-represented inputs and add them to the transaction */
+void AddInputs(CMutableTransaction& rawTx, const UniValue& inputs_in, bool rbf);
+
+/** Normalize univalue-represented outputs and add them to the transaction */
+void AddOutputs(CMutableTransaction& rawTx, const UniValue& outputs_in);
+
 /** Create a transaction from univalue parameters */
 CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, std::optional<bool> rbf);
 

src/wallet/feebumper.cpp

@@ -155,7 +155,7 @@ bool TransactionCanBeBumped(const CWallet& wallet, const uint256& txid)
 }
 
 Result CreateRateBumpTransaction(CWallet& wallet, const uint256& txid, const CCoinControl& coin_control, std::vector<bilingual_str>& errors,
-                                 CAmount& old_fee, CAmount& new_fee, CMutableTransaction& mtx, bool require_mine)
+                                 CAmount& old_fee, CAmount& new_fee, CMutableTransaction& mtx, bool require_mine, const std::vector<CTxOut>& outputs)
 {
     // We are going to modify coin control later, copy to re-use
     CCoinControl new_coin_control(coin_control);
@@ -222,11 +222,19 @@ Result CreateRateBumpTransaction(CWallet& wallet, const uint256& txid, const CCo
         return result;
     }
 
-    // Fill in recipients(and preserve a single change key if there is one)
-    // While we're here, calculate the output amount
-    std::vector<CRecipient> recipients;
+    // Calculate the old output amount.
     CAmount output_value = 0;
-    for (const auto& output : wtx.tx->vout) {
+    for (const auto& old_output : wtx.tx->vout) {
+        output_value += old_output.nValue;
+    }
+
+    old_fee = input_value - output_value;
+
+    // Fill in recipients (and preserve a single change key if there
+    // is one). If outputs vector is non-empty, replace original
+    // outputs with its contents, otherwise use original outputs.
+    std::vector<CRecipient> recipients;
+    for (const auto& output : outputs.empty() ? wtx.tx->vout : outputs) {
         if (!OutputIsChange(wallet, output)) {
             CRecipient recipient = {output.scriptPubKey, output.nValue, false};
             recipients.push_back(recipient);
@@ -235,11 +243,8 @@ Result CreateRateBumpTransaction(CWallet& wallet, const uint256& txid, const CCo
             ExtractDestination(output.scriptPubKey, change_dest);
             new_coin_control.destChange = change_dest;
         }
-        output_value += output.nValue;
     }
 
-    old_fee = input_value - output_value;
-
     if (coin_control.m_feerate) {
         // The user provided a feeRate argument.
         // We calculate this here to avoid compiler warning on the cs_wallet lock

src/wallet/feebumper.h

@@ -51,7 +51,8 @@ Result CreateRateBumpTransaction(CWallet& wallet,
     CAmount& old_fee,
     CAmount& new_fee,
     CMutableTransaction& mtx,
-    bool require_mine);
+    bool require_mine,
+    const std::vector<CTxOut>& outputs);
 
 //! Sign the new transaction,
 //! @return false if the tx couldn't be found or if it was

src/wallet/interfaces.cpp

@@ -291,7 +291,8 @@ class WalletImpl : public Wallet
         CAmount& new_fee,
         CMutableTransaction& mtx) override
     {
-        return feebumper::CreateRateBumpTransaction(*m_wallet.get(), txid, coin_control, errors, old_fee, new_fee, mtx, /* require_mine= */ true) == feebumper::Result::OK;
+        std::vector<CTxOut> outputs; // just an empty list of new recipients for now
+        return feebumper::CreateRateBumpTransaction(*m_wallet.get(), txid, coin_control, errors, old_fee, new_fee, mtx, /* require_mine= */ true, outputs) == feebumper::Result::OK;
     }
     bool signBumpTransaction(CMutableTransaction& mtx) override { return feebumper::SignTransaction(*m_wallet.get(), mtx); }
     bool commitBumpTransaction(const uint256& txid,

src/wallet/rpc/spend.cpp

@@ -956,6 +956,26 @@ RPCHelpMan signrawtransactionwithwallet()
     };
 }
 
+// Definition of allowed formats of specifying transaction outputs in
+// `bumpfee`, `psbtbumpfee`, `send` and `walletcreatefundedpsbt` RPCs.
+static std::vector<RPCArg> OutputsDoc()
+{
+    return
+    {
+        {"", RPCArg::Type::OBJ_USER_KEYS, RPCArg::Optional::OMITTED, "",
+            {
+                {"address", RPCArg::Type::AMOUNT, RPCArg::Optional::NO, "A key-value pair. The key (string) is the bitcoin address,\n"
+                         "the value (float or string) is the amount in " + CURRENCY_UNIT + ""},
+            },
+        },
+        {"", RPCArg::Type::OBJ, RPCArg::Optional::OMITTED, "",
+            {
+                {"data", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "A key-value pair. The key must be \"data\", the value is hex-encoded data"},
+            },
+        },
+    };
+}
+
 static RPCHelpMan bumpfee_helper(std::string method_name)
 {
     const bool want_psbt = method_name == "psbtbumpfee";
@@ -992,7 +1012,12 @@ static RPCHelpMan bumpfee_helper(std::string method_name)
                              "still be replaceable in practice, for example if it has unconfirmed ancestors which\n"
                              "are replaceable).\n"},
                     {"estimate_mode", RPCArg::Type::STR, RPCArg::Default{"unset"}, "The fee estimate mode, must be one of (case insensitive):\n"
-                     "\"" + FeeModes("\"\n\"") + "\""},
+                             "\"" + FeeModes("\"\n\"") + "\""},
+                    {"outputs", RPCArg::Type::ARR, RPCArg::Default{UniValue::VARR}, "New outputs (key-value pairs) which will replace\n"
+                             "the original ones, if provided. Each address can only appear once and there can\n"
+                             "only be one \"data\" object.\n",
+                        OutputsDoc(),
+                        RPCArgOptions{.skip_type_check = true}},
                 },
                 RPCArgOptions{.oneline_description="options"}},
         },
@@ -1029,6 +1054,7 @@ static RPCHelpMan bumpfee_helper(std::string method_name)
     coin_control.fAllowWatchOnly = pwallet->IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS);
     // optional parameters
     coin_control.m_signal_bip125_rbf = true;
+    std::vector<CTxOut> outputs;
 
     if (!request.params[1].isNull()) {
         UniValue options = request.params[1];
@@ -1039,6 +1065,7 @@ static RPCHelpMan bumpfee_helper(std::string method_name)
                 {"fee_rate", UniValueType()}, // will be checked by AmountFromValue() in SetFeeEstimateMode()
                 {"replaceable", UniValueType(UniValue::VBOOL)},
                 {"estimate_mode", UniValueType(UniValue::VSTR)},
+                {"outputs", UniValueType()}, // will be checked by AddOutputs()
             },
             true, true);
 
@@ -1052,6 +1079,16 @@ static RPCHelpMan bumpfee_helper(std::string method_name)
             coin_control.m_signal_bip125_rbf = options["replaceable"].get_bool();
         }
         SetFeeEstimateMode(*pwallet, coin_control, conf_target, options["estimate_mode"], options["fee_rate"], /*override_min_fee=*/false);
+
+        // Prepare new outputs by creating a temporary tx and calling AddOutputs().
+        if (!options["outputs"].isNull()) {
+            if (options["outputs"].isArray() && options["outputs"].empty()) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, output argument cannot be an empty array");
+            }
+            CMutableTransaction tempTx;
+            AddOutputs(tempTx, options["outputs"]);
+            outputs = tempTx.vout;
+        }
     }
 
     // Make sure the results are valid at least up to the most recent block
@@ -1069,7 +1106,7 @@ static RPCHelpMan bumpfee_helper(std::string method_name)
     CMutableTransaction mtx;
     feebumper::Result res;
     // Targeting feerate bump.
-    res = feebumper::CreateRateBumpTransaction(*pwallet, hash, coin_control, errors, old_fee, new_fee, mtx, /*require_mine=*/ !want_psbt);
+    res = feebumper::CreateRateBumpTransaction(*pwallet, hash, coin_control, errors, old_fee, new_fee, mtx, /*require_mine=*/ !want_psbt, outputs);
     if (res != feebumper::Result::OK) {
         switch(res) {
             case feebumper::Result::INVALID_ADDRESS_OR_KEY:
@@ -1144,18 +1181,7 @@ RPCHelpMan send()
             {"outputs", RPCArg::Type::ARR, RPCArg::Optional::NO, "The outputs (key-value pairs), where none of the keys are duplicated.\n"
                     "That is, each address can only appear once and there can only be one 'data' object.\n"
                     "For convenience, a dictionary, which holds the key-value pairs directly, is also accepted.",
-                {
-                    {"", RPCArg::Type::OBJ_USER_KEYS, RPCArg::Optional::OMITTED, "",
-                        {
-                            {"address", RPCArg::Type::AMOUNT, RPCArg::Optional::NO, "A key-value pair. The key (string) is the bitcoin address, the value (float or string) is the amount in " + CURRENCY_UNIT + ""},
-                        },
-                        },
-                    {"", RPCArg::Type::OBJ, RPCArg::Optional::OMITTED, "",
-                        {
-                            {"data", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "A key-value pair. The key must be \"data\", the value is hex-encoded data"},
-                        },
-                    },
-                },
+                OutputsDoc(),
                 RPCArgOptions{.skip_type_check = true}},
             {"conf_target", RPCArg::Type::NUM, RPCArg::DefaultHint{"wallet -txconfirmtarget"}, "Confirmation target in blocks"},
             {"estimate_mode", RPCArg::Type::STR, RPCArg::Default{"unset"}, "The fee estimate mode, must be one of (case insensitive):\n"
@@ -1606,19 +1632,8 @@ RPCHelpMan walletcreatefundedpsbt()
                             "That is, each address can only appear once and there can only be one 'data' object.\n"
                             "For compatibility reasons, a dictionary, which holds the key-value pairs directly, is also\n"
                             "accepted as second parameter.",
-                        {
-                            {"", RPCArg::Type::OBJ_USER_KEYS, RPCArg::Optional::OMITTED, "",
-                                {
-                                    {"address", RPCArg::Type::AMOUNT, RPCArg::Optional::NO, "A key-value pair. The key (string) is the bitcoin address, the value (float or string) is the amount in " + CURRENCY_UNIT + ""},
-                                },
-                                },
-                            {"", RPCArg::Type::OBJ, RPCArg::Optional::OMITTED, "",
-                                {
-                                    {"data", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "A key-value pair. The key must be \"data\", the value is hex-encoded data"},
-                                },
-                            },
-                        },
-                     RPCArgOptions{.skip_type_check = true}},
+                        OutputsDoc(),
+                        RPCArgOptions{.skip_type_check = true}},
                     {"locktime", RPCArg::Type::NUM, RPCArg::Default{0}, "Raw locktime. Non-0 value also locktime-activates inputs"},
                     {"options", RPCArg::Type::OBJ, RPCArg::Optional::OMITTED, "",
                         Cat<std::vector<RPCArg>>(

test/functional/wallet_bumpfee.py

@@ -81,7 +81,7 @@ def run_test(self):
 
         self.log.info("Running tests")
         dest_address = peer_node.getnewaddress()
-        for mode in ["default", "fee_rate"]:
+        for mode in ["default", "fee_rate", "new_outputs"]:
             test_simple_bumpfee_succeeds(self, mode, rbf_node, peer_node, dest_address)
         self.test_invalid_parameters(rbf_node, peer_node, dest_address)
         test_segwit_bumpfee_succeeds(self, rbf_node, dest_address)
@@ -157,6 +157,14 @@ def test_invalid_parameters(self, rbf_node, peer_node, dest_address):
             assert_raises_rpc_error(-8, 'Invalid estimate_mode parameter, must be one of: "unset", "economical", "conservative"',
                 rbf_node.bumpfee, rbfid, {"estimate_mode": mode})
 
+        self.log.info("Test invalid outputs values")
+        assert_raises_rpc_error(-8, "Invalid parameter, output argument cannot be an empty array",
+                rbf_node.bumpfee, rbfid, {"outputs": []})
+        assert_raises_rpc_error(-8, "Invalid parameter, duplicated address: " + dest_address,
+                rbf_node.bumpfee, rbfid, {"outputs": [{dest_address: 0.1}, {dest_address: 0.2}]})
+        assert_raises_rpc_error(-8, "Invalid parameter, duplicate key: data",
+                rbf_node.bumpfee, rbfid, {"outputs": [{"data": "deadbeef"}, {"data": "deadbeef"}]})
+
         self.clear_mempool()
 
 
@@ -169,6 +177,10 @@ def test_simple_bumpfee_succeeds(self, mode, rbf_node, peer_node, dest_address):
     if mode == "fee_rate":
         bumped_psbt = rbf_node.psbtbumpfee(rbfid, {"fee_rate": str(NORMAL)})
         bumped_tx = rbf_node.bumpfee(rbfid, {"fee_rate": NORMAL})
+    elif mode == "new_outputs":
+        new_address = peer_node.getnewaddress()
+        bumped_psbt = rbf_node.psbtbumpfee(rbfid, {"outputs": {new_address: 0.0003}})
+        bumped_tx = rbf_node.bumpfee(rbfid, {"outputs": {new_address: 0.0003}})
     else:
         bumped_psbt = rbf_node.psbtbumpfee(rbfid)
         bumped_tx = rbf_node.bumpfee(rbfid)
@@ -192,6 +204,10 @@ def test_simple_bumpfee_succeeds(self, mode, rbf_node, peer_node, dest_address):
     bumpedwtx = rbf_node.gettransaction(bumped_tx["txid"])
     assert_equal(oldwtx["replaced_by_txid"], bumped_tx["txid"])
     assert_equal(bumpedwtx["replaces_txid"], rbfid)
+    # if this is a new_outputs test, check that outputs were indeed replaced
+    if mode == "new_outputs":
+        assert len(bumpedwtx["details"]) == 1
+        assert bumpedwtx["details"][0]["address"] == new_address
     self.clear_mempool()
 
 
@@ -628,12 +644,14 @@ def get_change_address(tx):
     self.clear_mempool()
 
 
-def spend_one_input(node, dest_address, change_size=Decimal("0.00049000")):
+def spend_one_input(node, dest_address, change_size=Decimal("0.00049000"), data=None):
     tx_input = dict(
         sequence=MAX_BIP125_RBF_SEQUENCE, **next(u for u in node.listunspent() if u["amount"] == Decimal("0.00100000")))
     destinations = {dest_address: Decimal("0.00050000")}
     if change_size > 0:
         destinations[node.getrawchangeaddress()] = change_size
+    if data:
+        destinations['data'] = data
     rawtx = node.createrawtransaction([tx_input], destinations)
     signedtx = node.signrawtransactionwithwallet(rawtx)
     txid = node.sendrawtransaction(signedtx["hex"])