Merge #19969: Send RPC bug fix and touch-ups

f7b331ea85d45c7337e527b6e77a45da7a689b7d rpc: add brackets to ConstructTransaction (Sjors Provoost)
d813d26f06248aaa7be3c698c87939cc777fafd0 [rpc] send: various touch-ups (Sjors Provoost)
0fc1c685e1ca68ca8ed2b35f623bbe6a9fc36d66 [rpc] send: fix parsing replaceable option (Sjors Provoost)
efc9b85e6f4aa431d308089874a18f0bbdcdd0fd Mark send RPC experimental (Sjors Provoost)

Pull request description:

  Followup based on #16378 nits. It also fixes an argument parsing error (uncaught because the test wasn't sufficiently thorough).

  I marked the RPC as experimental so we can tweak it a bit over the next release cycle.

ACKs for top commit:
  meshcollider:
    utACK f7b331ea85d45c7337e527b6e77a45da7a689b7d
  fjahr:
    utACK f7b331ea85d45c7337e527b6e77a45da7a689b7d
  kallewoof:
    ACK f7b331ea85d45c7337e527b6e77a45da7a689b7d

Tree-SHA512: 82dd8ac76a6558872db3f5249d4d6440469400aaa339153bc627d1ee673a91ecfadecb486bc1939ba87ebbd80e26ff29698e93e358599f3d26fde0e526892afe

4 files changed, 39 insertions, 32 deletions

diff --git a/doc/release-notes-16378.md b/doc/release-notes-16378.md
index b006ea1a56..958633e780 100644
--- a/doc/release-notes-16378.md
+++ b/doc/release-notes-16378.md
@@ -1,5 +1,6 @@
 RPC
 ---
 - A new `send` RPC with similar syntax to `walletcreatefundedpsbt`, including
-  support for coin selection and a custom fee rate. Using the new `send` method
-  is encouraged: `sendmany` and `sendtoaddress` may be deprecated in a future release.
+  support for coin selection and a custom fee rate. The `send` RPC is experimental
+  and may change in subsequent releases. Using it is encouraged once it's no
+  longer experimental: `sendmany` and `sendtoaddress` may be deprecated in a future release.
diff --git a/src/rpc/rawtransaction_util.cpp b/src/rpc/rawtransaction_util.cpp
index cfe4575090..8dfbead0e4 100644
--- a/src/rpc/rawtransaction_util.cpp
+++ b/src/rpc/rawtransaction_util.cpp
@@ -21,14 +21,16 @@
 
 CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, bool rbf)
 {
-    if (outputs_in.isNull())
+    if (outputs_in.isNull()) {
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, output argument must be non-null");
+    }
 
     UniValue inputs;
-    if (inputs_in.isNull())
+    if (inputs_in.isNull()) {
         inputs = UniValue::VARR;
-    else
+    } 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();
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 2217bc2875..70e99a308e 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -3041,7 +3041,7 @@ void FundTransaction(CWallet* const pwallet, CMutableTransaction& tx, CAmount& f
                 {"lockUnspents", UniValueType(UniValue::VBOOL)},
                 {"lock_unspents", UniValueType(UniValue::VBOOL)},
                 {"locktime", UniValueType(UniValue::VNUM)},
-                {"feeRate", UniValueType()}, // will be checked below,
+                {"feeRate", UniValueType()}, // will be checked below
                 {"psbt", UniValueType(UniValue::VBOOL)},
                 {"subtractFeeFromOutputs", UniValueType(UniValue::VARR)},
                 {"subtract_fee_from_outputs", UniValueType(UniValue::VARR)},
@@ -3959,9 +3959,10 @@ static RPCHelpMan listlabels()
 static RPCHelpMan send()
 {
     return RPCHelpMan{"send",
+        "\nEXPERIMENTAL warning: this call may be changed in future releases.\n"
         "\nSend a transaction.\n",
         {
-            {"outputs", RPCArg::Type::ARR, RPCArg::Optional::NO, "a json array with outputs (key-value pairs), where none of the keys are duplicated.\n"
+            {"outputs", RPCArg::Type::ARR, RPCArg::Optional::NO, "A JSON array with 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.",
                 {
@@ -3993,7 +3994,7 @@ static RPCHelpMan send()
                     {"include_watching", RPCArg::Type::BOOL, /* default */ "true for watch-only wallets, otherwise false", "Also select inputs which are watch only.\n"
                                           "Only solvable inputs can be used. Watch-only destinations are solvable if the public key and/or output script was imported,\n"
                                           "e.g. with 'importpubkey' or 'importmulti' with the 'pubkeys' or 'desc' field."},
-                    {"inputs", RPCArg::Type::ARR, /* default */ "empty array", "Specify inputs instead of adding them automatically. A json array of json objects",
+                    {"inputs", RPCArg::Type::ARR, /* default */ "empty array", "Specify inputs instead of adding them automatically. A JSON array of JSON objects",
                         {
                             {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The transaction id"},
                             {"vout", RPCArg::Type::NUM, RPCArg::Optional::NO, "The output number"},
@@ -4003,7 +4004,7 @@ static RPCHelpMan send()
                     {"locktime", RPCArg::Type::NUM, /* default */ "0", "Raw locktime. Non-0 value also locktime-activates inputs"},
                     {"lock_unspents", RPCArg::Type::BOOL, /* default */ "false", "Lock selected unspent outputs"},
                     {"psbt", RPCArg::Type::BOOL,  /* default */ "automatic", "Always return a PSBT, implies add_to_wallet=false."},
-                    {"subtract_fee_from_outputs", RPCArg::Type::ARR, /* default */ "empty array", "A json array of integers.\n"
+                    {"subtract_fee_from_outputs", RPCArg::Type::ARR, /* default */ "empty array", "A JSON array of integers.\n"
                     "The fee will be equally deducted from the amount of each specified output.\n"
                     "Those recipients will receive less bitcoins than you enter in their corresponding amount field.\n"
                     "If no outputs are specified here, the sender pays the fee.",
@@ -4027,8 +4028,8 @@ static RPCHelpMan send()
         },
         RPCExamples{""
         "\nSend with a fee rate of 1 satoshi per byte\n"
-        + HelpExampleCli("send", "'{\"" + EXAMPLE_ADDRESS[0] + "\": 0.1}' 1 sat/b\n" +
-            "\nCreate a transaction that should confirm the next block, with a specific input, and return result without adding to wallet or broadcasting to the network\n")
+        + HelpExampleCli("send", "'{\"" + EXAMPLE_ADDRESS[0] + "\": 0.1}' 1 sat/b\n") +
+            "\nCreate a transaction that should confirm the next block, with a specific input, and return result without adding to wallet or broadcasting to the network\n"
         + HelpExampleCli("send", "'{\"" + EXAMPLE_ADDRESS[0] + "\": 0.1}' 1 economical '{\"add_to_wallet\": false, \"inputs\": [{\"txid\":\"a08e6907dbbd3d809776dbfc5d82e371b764ed838b5655e72f463568df1aadf0\", \"vout\":1}]}'")
         },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
@@ -4079,7 +4080,7 @@ static RPCHelpMan send()
             int change_position;
             bool rbf = pwallet->m_signal_rbf;
             if (options.exists("replaceable")) {
-                rbf = options["add_to_wallet"].get_bool();
+                rbf = options["replaceable"].get_bool();
             }
             CMutableTransaction rawTx = ConstructTransaction(options["inputs"], request.params[0], options["locktime"], rbf);
             CCoinControl coin_control;
@@ -4096,7 +4097,7 @@ static RPCHelpMan send()
             // Make a blank psbt
             PartiallySignedTransaction psbtx(rawTx);
 
-            // Fill transaction with out data and sign
+            // Fill transaction with our data and sign
             bool complete = true;
             const TransactionError err = pwallet->FillPSBT(psbtx, complete, SIGHASH_ALL, true, false);
             if (err != TransactionError::OK) {
@@ -4108,13 +4109,11 @@ static RPCHelpMan send()
 
             UniValue result(UniValue::VOBJ);
 
-            // Serialize the PSBT
-            CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
-            ssTx << psbtx;
-            const std::string result_str = EncodeBase64(ssTx.str());
-
             if (psbt_opt_in || !complete || !add_to_wallet) {
-                result.pushKV("psbt", result_str);
+                // Serialize the PSBT
+                CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
+                ssTx << psbtx;
+                result.pushKV("psbt", EncodeBase64(ssTx.str()));
             }
 
             if (complete) {
diff --git a/test/functional/wallet_send.py b/test/functional/wallet_send.py
index b64d2030a4..4fdfad01c3 100755
--- a/test/functional/wallet_send.py
+++ b/test/functional/wallet_send.py
@@ -29,9 +29,9 @@ class WalletSendTest(BitcoinTestFramework):
 
     def test_send(self, from_wallet, to_wallet=None, amount=None, data=None,
                   arg_conf_target=None, arg_estimate_mode=None,
-                  conf_target=None, estimate_mode=None, add_to_wallet=None,psbt=None,
-                  inputs=None,add_inputs=None,change_address=None,change_position=None,change_type=None,
-                  include_watching=None,locktime=None,lock_unspents=None,replaceable=None,subtract_fee_from_outputs=None,
+                  conf_target=None, estimate_mode=None, add_to_wallet=None, psbt=None,
+                  inputs=None, add_inputs=None, change_address=None, change_position=None, change_type=None,
+                  include_watching=None, locktime=None, lock_unspents=None, replaceable=None, subtract_fee_from_outputs=None,
                   expect_error=None):
         assert (amount is None) != (data is None)
 
@@ -92,13 +92,13 @@ class WalletSendTest(BitcoinTestFramework):
             res = from_wallet.send(outputs=outputs, conf_target=arg_conf_target, estimate_mode=arg_estimate_mode, options=options)
         else:
             try:
-                assert_raises_rpc_error(expect_error[0],expect_error[1],from_wallet.send,
-                                        outputs=outputs,conf_target=arg_conf_target,estimate_mode=arg_estimate_mode,options=options)
+                assert_raises_rpc_error(expect_error[0], expect_error[1], from_wallet.send,
+                                        outputs=outputs, conf_target=arg_conf_target, estimate_mode=arg_estimate_mode, options=options)
             except AssertionError:
                 # Provide debug info if the test fails
                 self.log.error("Unexpected successful result:")
                 self.log.error(options)
-                res = from_wallet.send(outputs=outputs,conf_target=arg_conf_target,estimate_mode=arg_estimate_mode,options=options)
+                res = from_wallet.send(outputs=outputs, conf_target=arg_conf_target, estimate_mode=arg_estimate_mode, options=options)
                 self.log.error(res)
                 if "txid" in res and add_to_wallet:
                     self.log.error("Transaction details:")
@@ -131,7 +131,7 @@ class WalletSendTest(BitcoinTestFramework):
             assert tx
             assert_equal(tx["bip125-replaceable"], "yes" if replaceable else "no")
             # Ensure transaction exists in the mempool:
-            tx = from_wallet.getrawtransaction(res["txid"],True)
+            tx = from_wallet.getrawtransaction(res["txid"], True)
             assert tx
             if amount:
                 if subtract_fee_from_outputs:
@@ -164,7 +164,7 @@ class WalletSendTest(BitcoinTestFramework):
         self.nodes[1].createwallet(wallet_name="w2")
         w2 = self.nodes[1].get_wallet_rpc("w2")
         # w3 is a watch-only wallet, based on w2
-        self.nodes[1].createwallet(wallet_name="w3",disable_private_keys=True)
+        self.nodes[1].createwallet(wallet_name="w3", disable_private_keys=True)
         w3 = self.nodes[1].get_wallet_rpc("w3")
         for _ in range(3):
             a2_receive = w2.getnewaddress()
@@ -188,7 +188,7 @@ class WalletSendTest(BitcoinTestFramework):
         self.sync_blocks()
 
         # w4 has private keys enabled, but only contains watch-only keys (from w2)
-        self.nodes[1].createwallet(wallet_name="w4",disable_private_keys=False)
+        self.nodes[1].createwallet(wallet_name="w4", disable_private_keys=False)
         w4 = self.nodes[1].get_wallet_rpc("w4")
         for _ in range(3):
             a2_receive = w2.getnewaddress()
@@ -253,7 +253,7 @@ class WalletSendTest(BitcoinTestFramework):
         self.test_send(from_wallet=w0, to_wallet=w1, amount=1, conf_target=-1, estimate_mode="sat/b",
                        expect_error=(-3, "Amount out of range"))
         # Fee rate of 0.1 satoshi per byte should throw an error
-        # TODO: error should say 1.000 sat/b
+        # TODO: error should use sat/b
         self.test_send(from_wallet=w0, to_wallet=w1, amount=1, conf_target=0.1, estimate_mode="sat/b",
                        expect_error=(-4, "Fee rate (0.00000100 BTC/kB) is lower than the minimum fee rate setting (0.00001000 BTC/kB)"))
 
@@ -325,11 +325,16 @@ class WalletSendTest(BitcoinTestFramework):
         locked_coins = w0.listlockunspent()
         assert_equal(len(locked_coins), 1)
         # Locked coins are automatically unlocked when manually selected
-        self.test_send(from_wallet=w0, to_wallet=w1, amount=1, inputs=[utxo1],add_to_wallet=False)
+        res = self.test_send(from_wallet=w0, to_wallet=w1, amount=1, inputs=[utxo1], add_to_wallet=False)
+        assert res["complete"]
 
         self.log.info("Replaceable...")
-        self.test_send(from_wallet=w0, to_wallet=w1, amount=1, add_to_wallet=False, replaceable=True)
-        self.test_send(from_wallet=w0, to_wallet=w1, amount=1, add_to_wallet=False, replaceable=False)
+        res = self.test_send(from_wallet=w0, to_wallet=w1, amount=1, add_to_wallet=True, replaceable=True)
+        assert res["complete"]
+        assert_equal(self.nodes[0].gettransaction(res["txid"])["bip125-replaceable"], "yes")
+        res = self.test_send(from_wallet=w0, to_wallet=w1, amount=1, add_to_wallet=True, replaceable=False)
+        assert res["complete"]
+        assert_equal(self.nodes[0].gettransaction(res["txid"])["bip125-replaceable"], "no")
 
         self.log.info("Subtract fee from output")
         self.test_send(from_wallet=w0, to_wallet=w1, amount=1, subtract_fee_from_outputs=[0])