Merge bitcoin/bitcoin#25610: wallet, rpc: Opt in to RBF by default

ab3c06db1aed979847158505f3df1dcea9fd6c2b doc: Release notes for default RBF (Andrew Chow)
61d9149e7804e2cec8fecf4150837344322eb301 rpc: Default rbf enabled (Andrew Chow)
e3c33637bac7db8ae56ab497df10911fad773981 wallet: Enable -walletrbf by default (Andrew Chow)

Pull request description:

  The GUI currently opts in to RBF by default, but RPCs do not, and `-walletrbf` is default disabled. This PR makes the default in those two places to also opt in.

  The last time this was proposed (#9527), the primary objections were the novelty at the time, the inability to bump transactions, and the gui not having the option to disable rbf. In the 5 years since, RBF usage has steadily grown, with ~27% of txs opting in. The GUI has the option to enable/disable RBF, and is also defaulted to having it enabled. And we have the ability to bump RBF'd transactions in both the RPC and the GUI. So I think it makes sense to finally change the default to always opt in to RBF.

ACKs for top commit:
  darosior:
    reACK ab3c06db1aed979847158505f3df1dcea9fd6c2b
  aureleoules:
    ACK ab3c06db1aed979847158505f3df1dcea9fd6c2b.
  glozow:
    utACK ab3c06db1a

Tree-SHA512: 81b012c5033e270f86a87a6a196ccc549eb54b158eebf88e917cc6621d40d7bdcd1566b602688907dd5d364b95a557b29f97dce869cea512e339588262c027b6

4 files changed, 10 insertions, 8 deletions

diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 9ec506b0fb..7ffb499330 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -157,7 +157,7 @@ static std::vector<RPCArg> CreateTxDoc()
             },
         },
         {"locktime", RPCArg::Type::NUM, RPCArg::Default{0}, "Raw locktime. Non-0 value also locktime-activates inputs"},
-        {"replaceable", RPCArg::Type::BOOL, RPCArg::Default{false}, "Marks this transaction as BIP125-replaceable.\n"
+        {"replaceable", RPCArg::Type::BOOL, RPCArg::Default{true}, "Marks this transaction as BIP125-replaceable.\n"
                 "Allows this transaction to be replaced by a transaction with higher fees. If provided, it is an error if explicit sequence numbers are incompatible."},
     };
 }
@@ -302,7 +302,7 @@ static RPCHelpMan createrawtransaction()
         }, true
     );
 
-    bool rbf = false;
+    std::optional<bool> rbf;
     if (!request.params[3].isNull()) {
         rbf = request.params[3].isTrue();
     }
@@ -1451,7 +1451,7 @@ static RPCHelpMan createpsbt()
         }, true
     );
 
-    bool rbf = false;
+    std::optional<bool> rbf;
     if (!request.params[3].isNull()) {
         rbf = request.params[3].isTrue();
     }
diff --git a/src/rpc/rawtransaction_util.cpp b/src/rpc/rawtransaction_util.cpp
index 86b5b7e960..b06e9f6e4b 100644
--- a/src/rpc/rawtransaction_util.cpp
+++ b/src/rpc/rawtransaction_util.cpp
@@ -21,7 +21,7 @@
 #include <util/strencodings.h>
 #include <util/translation.h>
 
-CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, bool rbf)
+CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, std::optional<bool> rbf)
 {
     if (outputs_in.isNull()) {
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, output argument must be non-null");
@@ -60,7 +60,8 @@ CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniVal
             throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, vout cannot be negative");
 
         uint32_t nSequence;
-        if (rbf) {
+
+        if (rbf.value_or(true)) {
             nSequence = MAX_BIP125_RBF_SEQUENCE; /* CTxIn::SEQUENCE_FINAL - 2 */
         } else if (rawTx.nLockTime) {
             nSequence = CTxIn::MAX_SEQUENCE_NONFINAL; /* CTxIn::SEQUENCE_FINAL - 1 */
@@ -132,7 +133,7 @@ CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniVal
         }
     }
 
-    if (rbf && rawTx.vin.size() > 0 && !SignalsOptInRBF(CTransaction(rawTx))) {
+    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");
     }
 
diff --git a/src/rpc/rawtransaction_util.h b/src/rpc/rawtransaction_util.h
index c3eb1417f8..9b5c9f08d4 100644
--- a/src/rpc/rawtransaction_util.h
+++ b/src/rpc/rawtransaction_util.h
@@ -7,6 +7,7 @@
 
 #include <map>
 #include <string>
+#include <optional>
 
 struct bilingual_str;
 class FillableSigningProvider;
@@ -38,6 +39,6 @@ void SignTransactionResultToJSON(CMutableTransaction& mtx, bool complete, const
 void ParsePrevouts(const UniValue& prevTxsUnival, FillableSigningProvider* keystore, std::map<COutPoint, Coin>& coins);
 
 /** Create a transaction from univalue parameters */
-CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, bool rbf);
+CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, std::optional<bool> rbf);
 
 #endif // BITCOIN_RPC_RAWTRANSACTION_UTIL_H
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 15f5917040..abab4a2a9b 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -99,7 +99,7 @@ static const bool DEFAULT_WALLET_REJECT_LONG_CHAINS{true};
 //! -txconfirmtarget default
 static const unsigned int DEFAULT_TX_CONFIRM_TARGET = 6;
 //! -walletrbf default
-static const bool DEFAULT_WALLET_RBF = false;
+static const bool DEFAULT_WALLET_RBF = true;
 static const bool DEFAULT_WALLETBROADCAST = true;
 static const bool DEFAULT_DISABLE_WALLET = false;
 static const bool DEFAULT_WALLETCROSSCHAIN = false;