RPC/Wallet: Add RBF support for fundrawtransaction

Author: luke-jr

src/wallet/rpcwallet.cpp

@@ -2629,7 +2629,7 @@ UniValue fundrawtransaction(const JSONRPCRequest& request)
         return NullUniValue;
     }
 
-    if (request.fHelp || request.params.size() < 1 || request.params.size() > 2)
+    if (request.fHelp || request.params.size() < 1 || request.params.size() > 3)
         throw std::runtime_error(
                             "fundrawtransaction \"hexstring\" ( options )\n"
                             "\nAdd inputs to a transaction until it has enough in value to meet its out value.\n"
@@ -2658,6 +2658,7 @@ UniValue fundrawtransaction(const JSONRPCRequest& request)
                             "                              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.\n"
                             "                                  [vout_index,...]\n"
+                            "     \"optIntoRbf\"             (boolean, optional) Allow this transaction to be replaced by a transaction with higher fees\n"
                             "   }\n"
                             "                         for backward compatibility: passing in a true instead of an object will result in {\"includeWatching\":true}\n"
                             "\nResult:\n"
@@ -2709,6 +2710,7 @@ UniValue fundrawtransaction(const JSONRPCRequest& request)
                 {"reserveChangeKey", UniValueType(UniValue::VBOOL)},
                 {"feeRate", UniValueType()}, // will be checked below
                 {"subtractFeeFromOutputs", UniValueType(UniValue::VARR)},
+                {"optIntoRbf", UniValueType(UniValue::VBOOL)},
             },
             true, true);
 
@@ -2741,6 +2743,10 @@ UniValue fundrawtransaction(const JSONRPCRequest& request)
 
         if (options.exists("subtractFeeFromOutputs"))
             subtractFeeFromOutputs = options["subtractFeeFromOutputs"].get_array();
+
+        if (options.exists("optIntoRbf")) {
+            coinControl.signalRbf = options["optIntoRbf"].get_bool();
+        }
       }
     }