wallet_rpc_server: expose change amount in transfer entries

src/wallet/wallet_rpc_server.cpp

@@ -520,6 +520,7 @@ namespace tools
     entry.fee = pd.m_amount_in - pd.m_amount_out;
     uint64_t change = pd.m_change == (uint64_t)-1 ? 0 : pd.m_change; // change may not be known
     entry.amount = pd.m_amount_in - change - entry.fee;
+    entry.change_amount = change;
     entry.note = m_wallet->get_tx_note(txid);
 
     for (const auto &d: pd.m_dests) {
@@ -548,6 +549,7 @@ namespace tools
     entry.timestamp = pd.m_timestamp;
     entry.fee = pd.m_amount_in - pd.m_amount_out;
     entry.amount = pd.m_amount_in - pd.m_change - entry.fee;
+    entry.change_amount = pd.m_change;
     entry.unlock_time = pd.m_tx.unlock_time;
     entry.locked = true;
     entry.note = m_wallet->get_tx_note(txid);

src/wallet/wallet_rpc_server_commands_defs.h

@@ -47,7 +47,7 @@
 // advance which version they will stop working with
 // Don't go over 32767 for any of these
 #define WALLET_RPC_VERSION_MAJOR 1
-#define WALLET_RPC_VERSION_MINOR 31
+#define WALLET_RPC_VERSION_MINOR 32
 #define MAKE_WALLET_RPC_VERSION(major,minor) (((major)<<16)|(minor))
 #define WALLET_RPC_VERSION MAKE_WALLET_RPC_VERSION(WALLET_RPC_VERSION_MAJOR, WALLET_RPC_VERSION_MINOR)
 namespace tools
@@ -1454,6 +1454,7 @@ namespace wallet_rpc
     uint64_t amount;
     amounts_container amounts;
     uint64_t fee;
+    uint64_t change_amount;
     std::string note;
     std::list<transfer_destination> destinations;
     std::string type;
@@ -1474,6 +1475,7 @@ namespace wallet_rpc
       KV_SERIALIZE(amount)
       KV_SERIALIZE(amounts)
       KV_SERIALIZE(fee)
+      KV_SERIALIZE_OPT(change_amount, (uint64_t)0)
       KV_SERIALIZE(note)
       KV_SERIALIZE(destinations)
       KV_SERIALIZE(type)

tests/functional_tests/transfer.py

@@ -204,6 +204,13 @@ class TransferTest():
         assert e.address == '42ey1afDFnn4886T7196doS9GPMzexD9gXpsZJDwVjeRVdFCSoHnv7KPbBeGpzJBzHRCAs9UxqeoyFQMYbqSWYTfJJQAWDm'
         assert e.double_spend_seen == False
         assert not 'confirmations' in e or e.confirmations == 0
+        assert e.change_amount > 0
+
+        res = self.wallet[0].get_transfer_by_txid(txid)
+        assert len(res.transfers) == 1
+        assert res.transfers[0] == res.transfer
+        assert res.transfer.type == 'pending'
+        assert res.transfer.change_amount == e.change_amount
 
         running_balances[0] -= fee
 
@@ -235,6 +242,7 @@ class TransferTest():
         assert e.address == '42ey1afDFnn4886T7196doS9GPMzexD9gXpsZJDwVjeRVdFCSoHnv7KPbBeGpzJBzHRCAs9UxqeoyFQMYbqSWYTfJJQAWDm'
         assert e.double_spend_seen == False
         assert e.confirmations == 1
+        assert e.change_amount > 0
 
         res = self.wallet[0].get_height()
         wallet_height = res.height
@@ -256,6 +264,7 @@ class TransferTest():
         assert t.address == '42ey1afDFnn4886T7196doS9GPMzexD9gXpsZJDwVjeRVdFCSoHnv7KPbBeGpzJBzHRCAs9UxqeoyFQMYbqSWYTfJJQAWDm'
         assert t.double_spend_seen == False
         assert t.confirmations == 1
+        assert t.change_amount == e.change_amount
 
         res = self.wallet[0].get_balance()
         assert res.balance == running_balances[0]