Merge #330: add option to subtract fee from peg-out output amount

ed63547 add basic peg-out functional testing (Gregory Sanders)
0328059 add optional subtract fee argument to sendtomainchain (Gregory Sanders)

qa/rpc-tests/pegging.py

@@ -173,6 +173,13 @@ try:
 
     addr = bitcoin.getnewaddress()
 
+    # First, blackhole all 21M bitcoin that already exist(and test subtractfrom)
+    assert(sidechain.getwalletinfo()["balance"]["bitcoin"] == 21000000)
+    sidechain.sendtomainchain(addr, 21000000, True)
+    assert("bitcoin" not in sidechain.getwalletinfo()["balance"])
+
+    sidechain.generate(101)
+
     addrs = sidechain.getpeginaddress()
     txid1 = bitcoin.sendtoaddress(addrs["mainchain_address"], 24)
     # 10+2 confirms required to get into mempool and confirm
@@ -296,6 +303,48 @@ try:
     # is awaiting further validation, nodes reject subsequent blocks
     # even ones they create
     sync_all(sidechain, sidechain2, False)
+    print("Now send funds out in two stages, partial, and full")
+    some_btc_addr = bitcoin.getnewaddress()
+    bal_1 = sidechain.getwalletinfo()["balance"]["bitcoin"]
+    try:
+        sidechain.sendtomainchain(some_btc_addr, bal_1 + 1)
+        raise Exception("Sending out too much; should have failed")
+    except JSONRPCException as e:
+        assert("Insufficient funds" in e.error["message"])
+        pass
+
+    assert(sidechain.getwalletinfo()["balance"]["bitcoin"] == bal_1)
+    try:
+        sidechain.sendtomainchain(some_btc_addr+"b", bal_1 - 1)
+        raise Exception("Sending to invalid address; should have failed")
+    except JSONRPCException as e:
+        assert("Invalid Bitcoin address" in e.error["message"])
+        pass
+
+    assert(sidechain.getwalletinfo()["balance"]["bitcoin"] == bal_1)
+    try:
+        sidechain.sendtomainchain("1Nro9WkpaKm9axmcfPVp79dAJU1Gx7VmMZ", bal_1 - 1)
+        raise Exception("Sending to mainchain address when should have been testnet; should have failed")
+    except JSONRPCException as e:
+        assert("Invalid Bitcoin address" in e.error["message"])
+        pass
+
+    assert(sidechain.getwalletinfo()["balance"]["bitcoin"] == bal_1)
+
+    peg_out_txid = sidechain.sendtomainchain(some_btc_addr, 1)
+
+    peg_out_details = sidechain.decoderawtransaction(sidechain.getrawtransaction(peg_out_txid))
+    # peg-out, change, fee(which is the last)
+    assert(len(peg_out_details["vout"]) == 3)
+    assert(peg_out_details["vout"][0]["value"] == 1 or peg_out_details["vout"][1]["value"] == 1)
+
+    bal_2 = sidechain.getwalletinfo()["balance"]["bitcoin"]
+    # Make sure balance went down
+    assert(bal_2 + 1 < bal_1)
+
+    sidechain.sendtomainchain(some_btc_addr, bal_2, True)
+
+    assert("bitcoin" not in sidechain.getwalletinfo()["balance"])
 
     print("Success!")
 

src/rpc/client.cpp

@@ -137,6 +137,7 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "getmempooldescendants", 1, "verbose" },
     { "bumpfee", 1, "options" },
     { "testproposedblock", 1, "acceptnonstd" },
+    { "sendtomainchain", 2, "subtractfeefromamount"},
     // Echo with conversion (For testing only)
     { "echojson", 0, "arg0" },
     { "echojson", 1, "arg1" },

src/wallet/rpcwallet.cpp

@@ -3446,14 +3446,15 @@ UniValue sendtomainchain(const JSONRPCRequest& request)
     if (!EnsureWalletIsAvailable(request.fHelp))
         return NullUniValue;
 
-    if (request.fHelp || request.params.size() != 2)
+    if (request.fHelp || request.params.size() < 2 || request.params.size() > 3)
         throw runtime_error(
-            "sendtomainchain mainchainaddress amount\n"
+            "sendtomainchain mainchainaddress amount ( subtractfeefromamount )\n"
             "\nSends sidechain funds to the given mainchain address, through the federated withdraw mechanism\n"
             + HelpRequiringPassphrase() +
             "\nArguments:\n"
             "1. \"address\"        (string, required) The destination address on Bitcoin mainchain\n"
             "2. \"amount\"         (numeric, required) The amount being sent to Bitcoin mainchain\n"
+            "3. \"subtractfeefromamount\"  (boolean, optional, default=false) The fee will be deducted from the amount being pegged-out.\n"
             "\nResult:\n"
             "\"txid\"              (string) Transaction ID of the resulting sidechain transaction\n"
             "\nExamples:\n"
@@ -3473,6 +3474,11 @@ UniValue sendtomainchain(const JSONRPCRequest& request)
     if (nAmount <= 0)
         throw JSONRPCError(RPC_TYPE_ERROR, "Invalid amount for send");
 
+    bool subtract_fee = false;
+    if (request.params.size() > 2) {
+        subtract_fee = request.params[2].get_bool();
+    }
+
     // Parse Bitcoin address for destination, embed script
     CScript scriptPubKeyMainchain(GetScriptForDestination(address.Get()));
 
@@ -3487,7 +3493,7 @@ UniValue sendtomainchain(const JSONRPCRequest& request)
     EnsureWalletIsUnlocked();
 
     CWalletTx wtxNew;
-    SendMoney(scriptPubKey, nAmount, Params().GetConsensus().pegged_asset, false, CPubKey(), wtxNew, true);
+    SendMoney(scriptPubKey, nAmount, Params().GetConsensus().pegged_asset, subtract_fee, CPubKey(), wtxNew, true);
 
     std::string blinds;
     for (unsigned int i=0; i<wtxNew.tx->vout.size(); i++) {
@@ -4118,7 +4124,7 @@ static const CRPCCommand commands[] =
     { "wallet",             "setaccount",               &setaccount,               true,   {"address","account"} },
     { "wallet",             "reissueasset",             &reissueasset,             true,   {"asset", "assetamount"} },
     { "wallet",             "signblock",                &signblock,                true,   {} },
-    { "wallet",             "sendtomainchain",          &sendtomainchain,          false,  {} },
+    { "wallet",             "sendtomainchain",          &sendtomainchain,          false,  {"address", "amount", "subtractfeefromamount"} },
     { "wallet",             "destroyamount",            &destroyamount,            false,  {"asset", "amount", "comment"} },
     { "wallet",             "settxfee",                 &settxfee,                 true,   {"amount"} },
     { "wallet",             "signmessage",              &signmessage,              true,   {"address","message"} },