RPC/Mempool: Add "rbf_policy" to getmempoolinfo result

Author: luke-jr

src/rpc/mempool.cpp

@@ -727,6 +727,11 @@ UniValue MempoolInfoToJSON(const CTxMemPool& pool, const std::optional<MempoolHi
     ret.pushKV("incrementalrelayfee", ValueFromAmount(pool.m_opts.incremental_relay_feerate.GetFeePerK()));
     ret.pushKV("unbroadcastcount", uint64_t{pool.GetUnbroadcastTxs().size()});
     ret.pushKV("fullrbf", (pool.m_opts.rbf_policy == RBFPolicy::Always));
+    switch (pool.m_opts.rbf_policy) {
+    case RBFPolicy::Never : ret.pushKV("rbf_policy", "never"); break;
+    case RBFPolicy::OptIn : ret.pushKV("rbf_policy", "optin"); break;
+    case RBFPolicy::Always: ret.pushKV("rbf_policy", "always"); break;
+    }
 
     if (histogram_floors) {
         const MempoolHistogramFeeRates& floors{histogram_floors.value()};
@@ -810,6 +815,7 @@ static RPCHelpMan getmempoolinfo()
                 {RPCResult::Type::NUM, "incrementalrelayfee", "minimum fee rate increment for mempool limiting or replacement in " + CURRENCY_UNIT + "/kvB"},
                 {RPCResult::Type::NUM, "unbroadcastcount", "Current number of transactions that haven't passed initial broadcast yet"},
                 {RPCResult::Type::BOOL, "fullrbf", "True if the mempool accepts RBF without replaceability signaling inspection"},
+                {RPCResult::Type::STR, "rbf_policy", "Policy used for replacing conflicting transactions by fee (one of: never, optin, always)"},
                 {RPCResult::Type::OBJ_DYN, "fee_histogram", /*optional=*/true, "",
                     {
                         {RPCResult::Type::OBJ, "<fee_rate_group>", "Fee rate group named by its lower bound (in " + CURRENCY_ATOM + "/vB), identical to the \"from_feerate\" field below",

test/functional/feature_rbf.py

@@ -55,6 +55,14 @@ def set_test_params(self):
     def run_test(self):
         self.wallet = MiniWallet(self.nodes[0])
 
+        self.log.info("Running test RPC rbf_policy")
+        def test_rpc_rbf_policy():
+            assert_equal(self.nodes[0].getmempoolinfo()["rbf_policy"], 'optin')
+            assert_equal(self.nodes[1].getmempoolinfo()["rbf_policy"], 'optin')
+            assert_equal(self.nodes[2].getmempoolinfo()["rbf_policy"], 'never')
+            assert_equal(self.nodes[3].getmempoolinfo()["rbf_policy"], 'always')
+        test_rpc_rbf_policy()
+
         self.log.info("Running test simple doublespend...")
         self.test_simple_doublespend()
 
@@ -743,6 +751,7 @@ def test_fullrbf(self):
         confirmed_utxo = self.make_utxo(self.nodes[0], int(2 * COIN))
         self.restart_node(0, extra_args=["-mempoolfullrbf=1"])
         assert self.nodes[0].getmempoolinfo()["fullrbf"]
+        assert_equal(self.nodes[0].getmempoolinfo()["rbf_policy"], 'always')
 
         # Create an explicitly opt-out transaction
         optout_tx = self.wallet.send_self_transfer(