return address info in z_importviewingkey

qa/rpc-tests/wallet_nullifiers.py

@@ -122,10 +122,14 @@ class WalletNullifiersTest (BitcoinTestFramework):
             'total': node3mined + zsendmany2notevalue,
         })
 
-        # add node 1 address and node 2 viewing key to node 3
+        # Add node 1 address and node 2 viewing key to node 3
         myzvkey = self.nodes[2].z_exportviewingkey(myzaddr)
         self.nodes[3].importaddress(mytaddr1)
-        self.nodes[3].z_importviewingkey(myzvkey, 'whenkeyisnew', 1)
+        importvk_result = self.nodes[3].z_importviewingkey(myzvkey, 'whenkeyisnew', 1)
+
+        # Check results of z_importviewingkey
+        assert_equal(importvk_result["type"], "sprout")
+        assert_equal(importvk_result["address"], myzaddr)
 
         # Check the address has been imported
         assert_equal(myzaddr in self.nodes[3].z_listaddresses(), False)

qa/rpc-tests/wallet_sapling.py

@@ -144,11 +144,13 @@ class WalletSaplingTest(BitcoinTestFramework):
 
         # Verify importing a viewing key will update the nullifiers and witnesses correctly
         extfvk0 = self.nodes[0].z_exportviewingkey(saplingAddr0)
-        self.nodes[3].z_importviewingkey(extfvk0, "yes")
-        assert_equal(self.nodes[3].z_getbalance(saplingAddr0), Decimal('10'))
+        saplingAddrInfo0 = self.nodes[3].z_importviewingkey(extfvk0, "yes")
+        assert_equal(saplingAddrInfo0["type"], "sapling")
+        assert_equal(self.nodes[3].z_getbalance(saplingAddrInfo0["address"]), Decimal('10'))
         extfvk1 = self.nodes[1].z_exportviewingkey(saplingAddr1)
-        self.nodes[3].z_importviewingkey(extfvk1, "yes")
-        assert_equal(self.nodes[3].z_getbalance(saplingAddr1), Decimal('5'))
+        saplingAddrInfo1 = self.nodes[3].z_importviewingkey(extfvk1, "yes")
+        assert_equal(saplingAddrInfo0["type"], "sapling")
+        assert_equal(self.nodes[3].z_getbalance(saplingAddrInfo1["address"]), Decimal('5'))
 
         # Verify that z_gettotalbalance only includes watch-only addresses when requested
         assert_equal(self.nodes[3].z_gettotalbalance()['private'], '0.00')

src/wallet/rpcdump.cpp

@@ -783,6 +783,11 @@ UniValue z_importviewingkey(const UniValue& params, bool fHelp)
             "2. rescan             (string, optional, default=\"whenkeyisnew\") Rescan the wallet for transactions - can be \"yes\", \"no\" or \"whenkeyisnew\"\n"
             "3. startHeight        (numeric, optional, default=0) Block height to start rescan from\n"
             "\nNote: This call can take minutes to complete if rescan is true.\n"
+            "\nResult:\n"
+            "{\n"
+            "  \"type\" : \"xxxx\",                         (string) \"sprout\" or \"sapling\"\n"
+            "  \"address\" : \"address|DefaultAddress\",    (string) The address(sprout) or the DefaultAddress(sapling)\n"
+            "}\n"
             "\nExamples:\n"
             "\nImport a viewing key\n"
             + HelpExampleCli("z_importviewingkey", "\"vkey\"") +
@@ -832,13 +837,18 @@ UniValue z_importviewingkey(const UniValue& params, bool fHelp)
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid viewing key");
     }
 
+    auto addrInfo = boost::apply_visitor(libzcash::AddressInfoFromViewingKey{}, viewingkey);
+    UniValue result(UniValue::VOBJ);
+    result.pushKV("type", addrInfo.first);
+    result.pushKV("address", EncodePaymentAddress(addrInfo.second));
+
     auto addResult = boost::apply_visitor(AddViewingKeyToWallet(pwalletMain), viewingkey);
     if (addResult == SpendingKeyExists) {
         throw JSONRPCError(
             RPC_WALLET_ERROR,
             "The wallet already contains the private key for this viewing key");
     } else if (addResult == KeyAlreadyExists && fIgnoreExistingKey) {
-        return NullUniValue;
+        return result;
     }
     pwalletMain->MarkDirty();
     if (addResult == KeyNotAdded) {
@@ -850,7 +860,7 @@ UniValue z_importviewingkey(const UniValue& params, bool fHelp)
         pwalletMain->ScanForWalletTransactions(chainActive[nRescanHeight], true);
     }
 
-    return NullUniValue;
+    return result;
 }
 
 UniValue z_exportkey(const UniValue& params, bool fHelp)

src/zcash/Address.cpp

@@ -12,6 +12,16 @@ std::pair<std::string, PaymentAddress> AddressInfoFromSpendingKey::operator()(co
     throw std::invalid_argument("Cannot derive default address from invalid spending key");
 }
 
+std::pair<std::string, PaymentAddress> AddressInfoFromViewingKey::operator()(const SproutViewingKey &sk) const {
+    return std::make_pair("sprout", sk.address());
+}
+std::pair<std::string, PaymentAddress> AddressInfoFromViewingKey::operator()(const SaplingExtendedFullViewingKey &sk) const {
+    return std::make_pair("sapling", sk.DefaultAddress());
+}
+std::pair<std::string, PaymentAddress> AddressInfoFromViewingKey::operator()(const InvalidEncoding&) const {
+    throw std::invalid_argument("Cannot derive default address from invalid viewing key");
+}
+
 }
 
 bool IsValidPaymentAddress(const libzcash::PaymentAddress& zaddr) {

src/zcash/Address.hpp

@@ -25,6 +25,13 @@ public:
     std::pair<std::string, PaymentAddress> operator()(const InvalidEncoding&) const;
 };
 
+class AddressInfoFromViewingKey : public boost::static_visitor<std::pair<std::string, PaymentAddress>> {
+public:
+    std::pair<std::string, PaymentAddress> operator()(const SproutViewingKey&) const;
+    std::pair<std::string, PaymentAddress> operator()(const struct SaplingExtendedFullViewingKey&) const;
+    std::pair<std::string, PaymentAddress> operator()(const InvalidEncoding&) const;
+};
+
 }
 
 /** Check whether a PaymentAddress is not an InvalidEncoding. */