wallet: add outputs arguments to bumpfee and psbtbumpfee

Author: rodentrabies

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

@@ -958,7 +958,7 @@ RPCHelpMan signrawtransactionwithwallet()
 }
 
 // Definition of allowed formats of specifying transaction outputs in
-// `send` and `walletcreatefundedpsbt` RPCs.
+// `bumpfee`, `psbtbumpfee`, `send` and `walletcreatefundedpsbt` RPCs.
 static std::vector<RPCArg> OutputsDoc()
 {
     return
@@ -1013,7 +1013,12 @@ 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"}},
         },
@@ -1050,6 +1055,7 @@ 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];
@@ -1060,6 +1066,7 @@ 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);
 
@@ -1073,6 +1080,16 @@ 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
@@ -1090,7 +1107,7 @@ 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: