Add matching descriptors to scantxoutset output + tests

Author: sipa

src/rpc/blockchain.cpp

@@ -2074,6 +2074,7 @@ UniValue scantxoutset(const JSONRPCRequest& request)
             "    \"txid\" : \"transactionid\",     (string) The transaction id\n"
             "    \"vout\": n,                    (numeric) the vout value\n"
             "    \"scriptPubKey\" : \"script\",    (string) the script key\n"
+            "    \"desc\" : \"descriptor\",        (string) A specialized descriptor for the matched scriptPubKey\n"
             "    \"amount\" : x.xxx,             (numeric) The total amount in " + CURRENCY_UNIT + " of the unspent output\n"
             "    \"height\" : n,                 (numeric) Height of the unspent transaction output\n"
             "   }\n"
@@ -2108,6 +2109,7 @@ UniValue scantxoutset(const JSONRPCRequest& request)
             throw JSONRPCError(RPC_INVALID_PARAMETER, "Scan already in progress, use action \"abort\" or \"status\"");
         }
         std::set<CScript> needles;
+        std::map<CScript, std::string> descriptors;
         CAmount total_in = 0;
 
         // loop through the scan objects
@@ -2140,7 +2142,11 @@ UniValue scantxoutset(const JSONRPCRequest& request)
                 if (!desc->Expand(i, provider, scripts, provider)) {
                     throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, strprintf("Cannot derive script without private keys: '%s'", desc_str));
                 }
-                needles.insert(scripts.begin(), scripts.end());
+                for (const auto& script : scripts) {
+                    std::string inferred = InferDescriptor(script, provider)->ToString();
+                    needles.emplace(script);
+                    descriptors.emplace(std::move(script), std::move(inferred));
+                }
             }
         }
 
@@ -2173,6 +2179,7 @@ UniValue scantxoutset(const JSONRPCRequest& request)
             unspent.pushKV("txid", outpoint.hash.GetHex());
             unspent.pushKV("vout", (int32_t)outpoint.n);
             unspent.pushKV("scriptPubKey", HexStr(txo.scriptPubKey.begin(), txo.scriptPubKey.end()));
+            unspent.pushKV("desc", descriptors[txo.scriptPubKey]);
             unspent.pushKV("amount", ValueFromAmount(txo.nValue));
             unspent.pushKV("height", (int32_t)coin.nHeight);
 

test/functional/rpc_scantxoutset.py

@@ -10,6 +10,9 @@
 import shutil
 import os
 
+def descriptors(out):
+    return sorted(u['desc'] for u in out['unspents'])
+
 class ScantxoutsetTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 1
@@ -93,5 +96,10 @@ def run_test(self):
         assert_equal(self.nodes[0].scantxoutset("start", [ {"desc": "combo(tpubD6NzVbkrYhZ4WaWSyoBvQwbpLkojyoTZPRsgXELWz3Popb3qkjcJyJUGLnL4qHHoQvao8ESaAstxYSnhyswJ76uZPStJRJCTKvosUCJZL5B/1/1/*)", "range": 1499}])['total_amount'], Decimal("12.288"))
         assert_equal(self.nodes[0].scantxoutset("start", [ {"desc": "combo(tpubD6NzVbkrYhZ4WaWSyoBvQwbpLkojyoTZPRsgXELWz3Popb3qkjcJyJUGLnL4qHHoQvao8ESaAstxYSnhyswJ76uZPStJRJCTKvosUCJZL5B/1/1/*)", "range": 1500}])['total_amount'], Decimal("28.672"))
 
+        # Test the reported descriptors for a few matches
+        assert_equal(descriptors(self.nodes[0].scantxoutset("start", [ {"desc": "combo(tprv8ZgxMBicQKsPd7Uf69XL1XwhmjHopUGep8GuEiJDZmbQz6o58LninorQAfcKZWARbtRtfnLcJ5MQ2AtHcQJCCRUcMRvmDUjyEmNUWwx8UbK/0h/0'/*)", "range": 1499}])), ["pkh([0c5f9a1e/0'/0'/0]026dbd8b2315f296d36e6b6920b1579ca75569464875c7ebe869b536a7d9503c8c)", "pkh([0c5f9a1e/0'/0'/1]033e6f25d76c00bedb3a8993c7d5739ee806397f0529b1b31dda31ef890f19a60c)"])
+        assert_equal(descriptors(self.nodes[0].scantxoutset("start", [ "combo(tprv8ZgxMBicQKsPd7Uf69XL1XwhmjHopUGep8GuEiJDZmbQz6o58LninorQAfcKZWARbtRtfnLcJ5MQ2AtHcQJCCRUcMRvmDUjyEmNUWwx8UbK/1/1/0)"])), ["pkh([0c5f9a1e/1/1/0]03e1c5b6e650966971d7e71ef2674f80222752740fc1dfd63bbbd220d2da9bd0fb)"])
+        assert_equal(descriptors(self.nodes[0].scantxoutset("start", [ {"desc": "combo(tpubD6NzVbkrYhZ4WaWSyoBvQwbpLkojyoTZPRsgXELWz3Popb3qkjcJyJUGLnL4qHHoQvao8ESaAstxYSnhyswJ76uZPStJRJCTKvosUCJZL5B/1/1/*)", "range": 1500}])), ['pkh([0c5f9a1e/1/1/0]03e1c5b6e650966971d7e71ef2674f80222752740fc1dfd63bbbd220d2da9bd0fb)', 'pkh([0c5f9a1e/1/1/1500]03832901c250025da2aebae2bfb38d5c703a57ab66ad477f9c578bfbcd78abca6f)', 'pkh([0c5f9a1e/1/1/1]030d820fc9e8211c4169be8530efbc632775d8286167afd178caaf1089b77daba7)'])
+
 if __name__ == '__main__':
     ScantxoutsetTest().main()