Changes necessary now that zero values accepted in AmountFromValue

- Add an accept test for zero amounts, and a reject test for negative
  amounts
- Remove ugly hack in `settxfee` that is no longer necessary
- Do explicit zero checks in wallet RPC functions
- Don't add a check for zero amounts in `createrawtransaction` - this
  could be seen as a feature

src/test/rpc_tests.cpp

@@ -137,6 +137,9 @@ static UniValue ValueFromString(const std::string &str)
 
 BOOST_AUTO_TEST_CASE(rpc_parse_monetary_values)
 {
+    BOOST_CHECK_THROW(AmountFromValue(ValueFromString("-0.00000001")), UniValue);
+    BOOST_CHECK_EQUAL(AmountFromValue(ValueFromString("0")), 0LL);
+    BOOST_CHECK_EQUAL(AmountFromValue(ValueFromString("0.00000000")), 0LL);
     BOOST_CHECK_EQUAL(AmountFromValue(ValueFromString("0.00000001")), 1LL);
     BOOST_CHECK_EQUAL(AmountFromValue(ValueFromString("0.17622195")), 17622195LL);
     BOOST_CHECK_EQUAL(AmountFromValue(ValueFromString("0.5")), 50000000LL);

src/wallet/rpcwallet.cpp

@@ -433,6 +433,8 @@ UniValue sendtoaddress(const UniValue& params, bool fHelp)
 
     // Amount
     CAmount nAmount = AmountFromValue(params[1]);
+    if (nAmount <= 0)
+        throw JSONRPCError(RPC_TYPE_ERROR, "Invalid amount for send");
 
     // Wallet comments
     CWalletTx wtx;
@@ -824,6 +826,8 @@ UniValue movecmd(const UniValue& params, bool fHelp)
     string strFrom = AccountFromValue(params[0]);
     string strTo = AccountFromValue(params[1]);
     CAmount nAmount = AmountFromValue(params[2]);
+    if (nAmount <= 0)
+        throw JSONRPCError(RPC_TYPE_ERROR, "Invalid amount for send");
     if (params.size() > 3)
         // unused parameter, used to be nMinDepth, keep type-checking it though
         (void)params[3].get_int();
@@ -903,6 +907,8 @@ UniValue sendfrom(const UniValue& params, bool fHelp)
     if (!address.IsValid())
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Zcash address");
     CAmount nAmount = AmountFromValue(params[2]);
+    if (nAmount <= 0)
+        throw JSONRPCError(RPC_TYPE_ERROR, "Invalid amount for send");
     int nMinDepth = 1;
     if (params.size() > 3)
         nMinDepth = params[3].get_int();
@@ -1002,6 +1008,8 @@ UniValue sendmany(const UniValue& params, bool fHelp)
 
         CScript scriptPubKey = GetScriptForDestination(address.Get());
         CAmount nAmount = AmountFromValue(sendTo[name_]);
+        if (nAmount <= 0)
+            throw JSONRPCError(RPC_TYPE_ERROR, "Invalid amount for send");
         totalAmount += nAmount;
 
         bool fSubtractFeeFromAmount = false;
@@ -2227,9 +2235,7 @@ UniValue settxfee(const UniValue& params, bool fHelp)
     LOCK2(cs_main, pwalletMain->cs_wallet);
 
     // Amount
-    CAmount nAmount = 0;
-    if (params[0].get_real() != 0.0)
-        nAmount = AmountFromValue(params[0]);        // rejects 0.0 amounts
+    CAmount nAmount = AmountFromValue(params[0]);
 
     payTxFee = CFeeRate(nAmount, 1000);
     return true;
@@ -3471,4 +3477,3 @@ UniValue z_listoperationids(const UniValue& params, bool fHelp)
 
     return ret;
 }
-