From 16203d5df755fe8fc0c5ddc026714d87b504ff24 Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Sat, 13 Oct 2018 13:32:18 -0700
Subject: [PATCH] Add descriptors to listunspent and getaddressinfo + tests

---
 src/wallet/rpcwallet.cpp                | 13 ++++++
 test/functional/wallet_address_types.py | 56 +++++++++++++++++++++++++
 2 files changed, 69 insertions(+)

diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index dc39ba3001..46259535ac 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -20,6 +20,7 @@
 #include <rpc/rawtransaction.h>
 #include <rpc/server.h>
 #include <rpc/util.h>
+#include <script/descriptor.h>
 #include <script/sign.h>
 #include <shutdown.h>
 #include <timedata.h>
@@ -2623,6 +2624,7 @@ static UniValue listunspent(const JSONRPCRequest& request)
             "    \"redeemScript\" : n        (string) The redeemScript if scriptPubKey is P2SH\n"
             "    \"spendable\" : xxx,        (bool) Whether we have the private keys to spend this output\n"
             "    \"solvable\" : xxx,         (bool) Whether we know how to spend this output, ignoring the lack of keys\n"
+            "    \"desc\" : xxx,             (string, only when solvable) A descriptor for spending this output\n"
             "    \"safe\" : xxx              (bool) Whether this output is considered safe to spend. Unconfirmed transactions\n"
             "                              from outside keys and unconfirmed replacement transactions are considered unsafe\n"
             "                              and are not eligible for spending by fundrawtransaction and sendtoaddress.\n"
@@ -2740,6 +2742,10 @@ static UniValue listunspent(const JSONRPCRequest& request)
         entry.pushKV("confirmations", out.nDepth);
         entry.pushKV("spendable", out.fSpendable);
         entry.pushKV("solvable", out.fSolvable);
+        if (out.fSolvable) {
+            auto descriptor = InferDescriptor(scriptPubKey, *pwallet);
+            entry.pushKV("desc", descriptor->ToString());
+        }
         entry.pushKV("safe", out.fSafe);
         results.push_back(entry);
     }
@@ -3456,6 +3462,8 @@ UniValue getaddressinfo(const JSONRPCRequest& request)
             "  \"scriptPubKey\" : \"hex\",       (string) The hex-encoded scriptPubKey generated by the address\n"
             "  \"ismine\" : true|false,        (boolean) If the address is yours or not\n"
             "  \"iswatchonly\" : true|false,   (boolean) If the address is watchonly\n"
+            "  \"solvable\" : true|false,      (boolean) Whether we know how to spend coins sent to this address, ignoring the possible lack of private keys\n"
+            "  \"desc\" : \"desc\",            (string, optional) A descriptor for spending coins sent to this address (only when solvable)\n"
             "  \"isscript\" : true|false,      (boolean) If the key is a script\n"
             "  \"iswitness\" : true|false,     (boolean) If the address is a witness address\n"
             "  \"witness_version\" : version   (numeric, optional) The version number of the witness program\n"
@@ -3508,6 +3516,11 @@ UniValue getaddressinfo(const JSONRPCRequest& request)
 
     isminetype mine = IsMine(*pwallet, dest);
     ret.pushKV("ismine", bool(mine & ISMINE_SPENDABLE));
+    bool solvable = IsSolvable(*pwallet, scriptPubKey);
+    ret.pushKV("solvable", solvable);
+    if (solvable) {
+       ret.pushKV("desc", InferDescriptor(scriptPubKey, *pwallet)->ToString());
+    }
     ret.pushKV("iswatchonly", bool(mine & ISMINE_WATCH_ONLY));
     UniValue detail = DescribeWalletAddress(pwallet, dest);
     ret.pushKVs(detail);
diff --git a/test/functional/wallet_address_types.py b/test/functional/wallet_address_types.py
index 0f75045c9d..bafa556aad 100755
--- a/test/functional/wallet_address_types.py
+++ b/test/functional/wallet_address_types.py
@@ -99,6 +99,8 @@ class AddressTypeTest(BitcoinTestFramework):
         """Run sanity checks on an address."""
         info = self.nodes[node].getaddressinfo(address)
         assert(self.nodes[node].validateaddress(address)['isvalid'])
+        assert_equal(info.get('solvable'), True)
+
         if not multisig and typ == 'legacy':
             # P2PKH
             assert(not info['isscript'])
@@ -146,6 +148,47 @@ class AddressTypeTest(BitcoinTestFramework):
             # Unknown type
             assert(False)
 
+    def test_desc(self, node, address, multisig, typ, utxo):
+        """Run sanity checks on a descriptor reported by getaddressinfo."""
+        info = self.nodes[node].getaddressinfo(address)
+        assert('desc' in info)
+        assert_equal(info['desc'], utxo['desc'])
+        assert(self.nodes[node].validateaddress(address)['isvalid'])
+
+        # Use a ridiculously roundabout way to find the key origin info through
+        # the PSBT logic. However, this does test consistency between the PSBT reported
+        # fingerprints/paths and the descriptor logic.
+        psbt = self.nodes[node].createpsbt([{'txid':utxo['txid'], 'vout':utxo['vout']}],[{address:0.00010000}])
+        psbt = self.nodes[node].walletprocesspsbt(psbt, False, "ALL", True)
+        decode = self.nodes[node].decodepsbt(psbt['psbt'])
+        key_descs = {}
+        for deriv in decode['inputs'][0]['bip32_derivs']:
+            assert_equal(len(deriv['master_fingerprint']), 8)
+            assert_equal(deriv['path'][0], 'm')
+            key_descs[deriv['pubkey']] = '[' + deriv['master_fingerprint'] + deriv['path'][1:] + ']' + deriv['pubkey']
+
+        if not multisig and typ == 'legacy':
+            # P2PKH
+            assert_equal(info['desc'], "pkh(%s)" % key_descs[info['pubkey']])
+        elif not multisig and typ == 'p2sh-segwit':
+            # P2SH-P2WPKH
+            assert_equal(info['desc'], "sh(wpkh(%s))" % key_descs[info['pubkey']])
+        elif not multisig and typ == 'bech32':
+            # P2WPKH
+            assert_equal(info['desc'], "wpkh(%s)" % key_descs[info['pubkey']])
+        elif typ == 'legacy':
+            # P2SH-multisig
+            assert_equal(info['desc'], "sh(multi(2,%s,%s))" % (key_descs[info['pubkeys'][0]], key_descs[info['pubkeys'][1]]))
+        elif typ == 'p2sh-segwit':
+            # P2SH-P2WSH-multisig
+            assert_equal(info['desc'], "sh(wsh(multi(2,%s,%s)))" % (key_descs[info['embedded']['pubkeys'][0]], key_descs[info['embedded']['pubkeys'][1]]))
+        elif typ == 'bech32':
+            # P2WSH-multisig
+            assert_equal(info['desc'], "wsh(multi(2,%s,%s))" % (key_descs[info['pubkeys'][0]], key_descs[info['pubkeys'][1]]))
+        else:
+            # Unknown type
+            assert(False)
+
     def test_change_output_type(self, node_sender, destinations, expected_type):
         txid = self.nodes[node_sender].sendmany(dummy="", amounts=dict.fromkeys(destinations, 0.001))
         raw_tx = self.nodes[node_sender].getrawtransaction(txid)
@@ -198,6 +241,7 @@ class AddressTypeTest(BitcoinTestFramework):
             self.log.debug("Old balances are {}".format(old_balances))
             to_send = (old_balances[from_node] / 101).quantize(Decimal("0.00000001"))
             sends = {}
+            addresses = {}
 
             self.log.debug("Prepare sends")
             for n, to_node in enumerate(range(from_node, from_node + 4)):
@@ -228,6 +272,7 @@ class AddressTypeTest(BitcoinTestFramework):
 
                 # Output entry
                 sends[address] = to_send * 10 * (1 + n)
+                addresses[to_node] = (address, typ)
 
             self.log.debug("Sending: {}".format(sends))
             self.nodes[from_node].sendmany("", sends)
@@ -244,6 +289,17 @@ class AddressTypeTest(BitcoinTestFramework):
             self.nodes[5].generate(1)
             sync_blocks(self.nodes)
 
+            # Verify that the receiving wallet contains a UTXO with the expected address, and expected descriptor
+            for n, to_node in enumerate(range(from_node, from_node + 4)):
+                to_node %= 4
+                found = False
+                for utxo in self.nodes[to_node].listunspent():
+                    if utxo['address'] == addresses[to_node][0]:
+                        found = True
+                        self.test_desc(to_node, addresses[to_node][0], multisig, addresses[to_node][1], utxo)
+                        break
+                assert found
+
             new_balances = self.get_balances()
             self.log.debug("Check new balances: {}".format(new_balances))
             # We don't know what fee was set, so we can only check bounds on the balance of the sending node