rpc: add utxo's blockhash and number of confirmations to scantxoutset output

Author: luisschwab

src/rpc/blockchain.cpp

@@ -2190,7 +2190,7 @@ static RPCHelpMan scantxoutset()
             RPCResult{"when action=='start'; only returns after scan completes", RPCResult::Type::OBJ, "", "", {
                 {RPCResult::Type::BOOL, "success", "Whether the scan was completed"},
                 {RPCResult::Type::NUM, "txouts", "The number of unspent transaction outputs scanned"},
-                {RPCResult::Type::NUM, "height", "The current block height (index)"},
+                {RPCResult::Type::NUM, "height", "The block height at which the scan was done"},
                 {RPCResult::Type::STR_HEX, "bestblock", "The hash of the block at the tip of the chain"},
                 {RPCResult::Type::ARR, "unspents", "",
                 {
@@ -2203,6 +2203,8 @@ static RPCHelpMan scantxoutset()
                         {RPCResult::Type::STR_AMOUNT, "amount", "The total amount in " + CURRENCY_UNIT + " of the unspent output"},
                         {RPCResult::Type::BOOL, "coinbase", "Whether this is a coinbase output"},
                         {RPCResult::Type::NUM, "height", "Height of the unspent transaction output"},
+                        {RPCResult::Type::STR_HEX, "blockhash", "Blockhash of the unspent transaction output"},
+                        {RPCResult::Type::NUM, "confirmations", "Number of confirmations of the unspent transaction output when the scan was done"},
                     }},
                 }},
                 {RPCResult::Type::STR_AMOUNT, "total_amount", "The total amount of all found unspent outputs in " + CURRENCY_UNIT},
@@ -2292,17 +2294,20 @@ static RPCHelpMan scantxoutset()
             const COutPoint& outpoint = it.first;
             const Coin& coin = it.second;
             const CTxOut& txo = coin.out;
+            const CBlockIndex& coinb_block{*CHECK_NONFATAL(tip->GetAncestor(coin.nHeight))};
             input_txos.push_back(txo);
             total_in += txo.nValue;
 
             UniValue unspent(UniValue::VOBJ);
             unspent.pushKV("txid", outpoint.hash.GetHex());
-            unspent.pushKV("vout", (int32_t)outpoint.n);
+            unspent.pushKV("vout", outpoint.n);
             unspent.pushKV("scriptPubKey", HexStr(txo.scriptPubKey));
             unspent.pushKV("desc", descriptors[txo.scriptPubKey]);
             unspent.pushKV("amount", ValueFromAmount(txo.nValue));
             unspent.pushKV("coinbase", coin.IsCoinBase());
-            unspent.pushKV("height", (int32_t)coin.nHeight);
+            unspent.pushKV("height", coin.nHeight);
+            unspent.pushKV("blockhash", coinb_block.GetBlockHash().GetHex());
+            unspent.pushKV("confirmations", tip->nHeight - coin.nHeight + 1);
 
             unspents.push_back(std::move(unspent));
         }

test/functional/rpc_scantxoutset.py

@@ -120,7 +120,15 @@ def run_test(self):
         assert_equal(self.nodes[0].scantxoutset("status"), None)
         assert_equal(self.nodes[0].scantxoutset("abort"), False)
 
-        # check that first arg is needed
+        # Check that the blockhash and confirmations fields are correct
+        self.generate(self.nodes[0], 2)
+        unspent = self.nodes[0].scantxoutset("start", ["addr(mpQ8rokAhp1TAtJQR6F6TaUmjAWkAWYYBq)"])["unspents"][0]
+        blockhash = self.nodes[0].getblockhash(info["height"])
+        assert_equal(unspent["height"], info["height"])
+        assert_equal(unspent["blockhash"], blockhash)
+        assert_equal(unspent["confirmations"], 3)
+
+        # Check that first arg is needed
         assert_raises_rpc_error(-1, "scantxoutset \"action\" ( [scanobjects,...] )", self.nodes[0].scantxoutset)
 
         # Check that second arg is needed for start