rpc: output wallet descriptors for received entries in listsinceblock

The descriptor wallets allow an application to track coins of multiple
descriptors in a single wallet. However, such an application would not
previously be able to (easily) tell what received coin "belongs" to what
descriptor.

This commit tackles this issues by adding a "wallet_desc" entry to the
entries for received coins in 'listsinceblock'.

src/wallet/rpc/transactions.cpp

@@ -367,6 +367,7 @@ static void ListTransactions(const CWallet& wallet, const CWalletTx& wtx, int nM
                 entry.pushKV("involvesWatchonly", true);
             }
             MaybePushAddress(entry, r.destination);
+            PushParentDescriptors(wallet, wtx.tx->vout.at(r.vout).scriptPubKey, entry);
             if (wtx.IsCoinBase())
             {
                 if (wallet.GetTxDepthInMainChain(wtx) < 1)
@@ -418,7 +419,11 @@ static const std::vector<RPCResult> TransactionDescriptionString()
            {RPCResult::Type::NUM_TIME, "timereceived", "The time received expressed in " + UNIX_EPOCH_TIME + "."},
            {RPCResult::Type::STR, "comment", /*optional=*/true, "If a comment is associated with the transaction, only present if not empty."},
            {RPCResult::Type::STR, "bip125-replaceable", "(\"yes|no|unknown\") Whether this transaction could be replaced due to BIP125 (replace-by-fee);\n"
-               "may be unknown for unconfirmed transactions not in the mempool."}};
+               "may be unknown for unconfirmed transactions not in the mempool."},
+           {RPCResult::Type::ARR, "parent_descs", /*optional=*/true, "Only if 'category' is 'received'. List of parent descriptors for the scriptPubKey of this coin.", {
+               {RPCResult::Type::STR, "desc", "The descriptor string."},
+           }},
+           };
 }
 
 RPCHelpMan listtransactions()
@@ -709,6 +714,9 @@ RPCHelpMan gettransaction()
                                     "'send' category of transactions."},
                                 {RPCResult::Type::BOOL, "abandoned", /*optional=*/true, "'true' if the transaction has been abandoned (inputs are respendable). Only available for the \n"
                                      "'send' category of transactions."},
+                                {RPCResult::Type::ARR, "parent_descs", /*optional=*/true, "Only if 'category' is 'received'. List of parent descriptors for the scriptPubKey of this coin.", {
+                                    {RPCResult::Type::STR, "desc", "The descriptor string."},
+                                }},
                             }},
                         }},
                         {RPCResult::Type::STR_HEX, "hex", "Raw data for transaction"},

src/wallet/rpc/util.cpp

@@ -123,6 +123,15 @@ std::string LabelFromValue(const UniValue& value)
     return label;
 }
 
+void PushParentDescriptors(const CWallet& wallet, const CScript& script_pubkey, UniValue& entry)
+{
+    UniValue parent_descs(UniValue::VARR);
+    for (const auto& desc: wallet.GetWalletDescriptors(script_pubkey)) {
+        parent_descs.push_back(desc.descriptor->ToString());
+    }
+    entry.pushKV("parent_descs", parent_descs);
+}
+
 void HandleWalletError(const std::shared_ptr<CWallet> wallet, DatabaseStatus& status, bilingual_str& error)
 {
     if (!wallet) {

src/wallet/rpc/util.h

@@ -5,6 +5,8 @@
 #ifndef BITCOIN_WALLET_RPC_UTIL_H
 #define BITCOIN_WALLET_RPC_UTIL_H
 
+#include <script/script.h>
+
 #include <any>
 #include <memory>
 #include <string>
@@ -39,6 +41,8 @@ const LegacyScriptPubKeyMan& EnsureConstLegacyScriptPubKeyMan(const CWallet& wal
 bool GetAvoidReuseFlag(const CWallet& wallet, const UniValue& param);
 bool ParseIncludeWatchonly(const UniValue& include_watchonly, const CWallet& wallet);
 std::string LabelFromValue(const UniValue& value);
+//! Fetch parent descriptors of this scriptPubKey.
+void PushParentDescriptors(const CWallet& wallet, const CScript& script_pubkey, UniValue& entry);
 
 void HandleWalletError(const std::shared_ptr<CWallet> wallet, DatabaseStatus& status, bilingual_str& error);
 } //  namespace wallet

test/functional/wallet_listsinceblock.py

@@ -6,6 +6,7 @@
 
 from test_framework.address import key_to_p2wpkh
 from test_framework.blocktools import COINBASE_MATURITY
+from test_framework.descriptors import descsum_create
 from test_framework.key import ECKey
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.messages import MAX_BIP125_RBF_SEQUENCE
@@ -39,6 +40,7 @@ class ListSinceBlockTest(BitcoinTestFramework):
         self.test_double_send()
         self.double_spends_filtered()
         self.test_targetconfirmations()
+        self.test_desc()
 
     def test_no_blockhash(self):
         self.log.info("Test no blockhash")
@@ -383,5 +385,44 @@ class ListSinceBlockTest(BitcoinTestFramework):
         assert_equal(original_found, False)
         assert_equal(double_found, False)
 
+    def test_desc(self):
+        """Make sure we can track coins by descriptor."""
+        self.log.info("Test descriptor lookup by scriptPubKey.")
+
+        # Create a watchonly wallet tracking two multisig descriptors.
+        multi_a = descsum_create("wsh(multi(1,tpubD6NzVbkrYhZ4YBNjUo96Jxd1u4XKWgnoc7LsA1jz3Yc2NiDbhtfBhaBtemB73n9V5vtJHwU6FVXwggTbeoJWQ1rzdz8ysDuQkpnaHyvnvzR/*,tpubD6NzVbkrYhZ4YHdDGMAYGaWxMSC1B6tPRTHuU5t3BcfcS3nrF523iFm5waFd1pP3ZvJt4Jr8XmCmsTBNx5suhcSgtzpGjGMASR3tau1hJz4/*))")
+        multi_b = descsum_create("wsh(multi(1,tpubD6NzVbkrYhZ4YHdDGMAYGaWxMSC1B6tPRTHuU5t3BcfcS3nrF523iFm5waFd1pP3ZvJt4Jr8XmCmsTBNx5suhcSgtzpGjGMASR3tau1hJz4/*,tpubD6NzVbkrYhZ4Y2RLiuEzNQkntjmsLpPYDm3LTRBYynUQtDtpzeUKAcb9sYthSFL3YR74cdFgF5mW8yKxv2W2CWuZDFR2dUpE5PF9kbrVXNZ/*))")
+        self.nodes[0].createwallet(wallet_name="wo", descriptors=True, disable_private_keys=True)
+        wo_wallet = self.nodes[0].get_wallet_rpc("wo")
+        wo_wallet.importdescriptors([
+            {
+                "desc": multi_a,
+                "active": False,
+                "timestamp": "now",
+            },
+            {
+                "desc": multi_b,
+                "active": False,
+                "timestamp": "now",
+            },
+        ])
+
+        # Send a coin to each descriptor.
+        assert_equal(len(wo_wallet.listsinceblock()["transactions"]), 0)
+        addr_a = self.nodes[0].deriveaddresses(multi_a, 0)[0]
+        addr_b = self.nodes[0].deriveaddresses(multi_b, 0)[0]
+        self.nodes[2].sendtoaddress(addr_a, 1)
+        self.nodes[2].sendtoaddress(addr_b, 2)
+        self.generate(self.nodes[2], 1)
+
+        # We can identify on which descriptor each coin was received.
+        coins = wo_wallet.listsinceblock()["transactions"]
+        assert_equal(len(coins), 2)
+        coin_a = next(c for c in coins if c["amount"] == 1)
+        assert_equal(coin_a["parent_descs"][0], multi_a)
+        coin_b = next(c for c in coins if c["amount"] == 2)
+        assert_equal(coin_b["parent_descs"][0], multi_b)
+
+
 if __name__ == '__main__':
     ListSinceBlockTest().main()