Merge #11872: [rpc] createrawtransaction: Accept sorted outputs

fac70134a rpc: Update createrawtransaction examples (MarcoFalke)
fa06dfce0 [rpc] createrawtransaction: Accept sorted outputs (MarcoFalke)
8acd25d85 rpc: Allow typeAny in RPCTypeCheck (MarcoFalke)

Pull request description:

  The second parameter of the `createrawtransaction` is a dictionary of the outputs. This comes with at least two drawbacks:

  * In case of duplicate keys, either of them might silently disappear, with no user feedback at all. A user needs to make other mistakes, but this could eventually lead to abnormal tx fees.
  * A dictionary does not guarantee that keys are sorted. Again, a user needs to keep this in mind, as it could eventually lead to excessive tx fees.

  Even though my scenario of loss-of-funds is unlikely to happen, I see it as a inconvenience that should be fixed.

Tree-SHA512: cd562f34f7f9f79c7d3433805971325c388c2035611be283980f4049066a622df4f0afdc11d7ac96662260ec0115147cb65e1ab5268f5a1b063242f3fe425f77

4 files changed, 57 insertions, 29 deletions

diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 8dcfb48e9a..883ec71747 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -316,9 +316,10 @@ UniValue verifytxoutproof(const JSONRPCRequest& request)
 
 UniValue createrawtransaction(const JSONRPCRequest& request)
 {
-    if (request.fHelp || request.params.size() < 2 || request.params.size() > 4)
+    if (request.fHelp || request.params.size() < 2 || request.params.size() > 4) {
         throw std::runtime_error(
-            "createrawtransaction [{\"txid\":\"id\",\"vout\":n},...] {\"address\":amount,\"data\":\"hex\",...} ( locktime ) ( replaceable )\n"
+            // clang-format off
+            "createrawtransaction [{\"txid\":\"id\",\"vout\":n},...] [{\"address\":amount},{\"data\":\"hex\"},...] ( locktime ) ( replaceable )\n"
             "\nCreate a transaction spending the given inputs and creating new outputs.\n"
             "Outputs can be addresses or data.\n"
             "Returns hex-encoded raw transaction.\n"
@@ -329,18 +330,23 @@ UniValue createrawtransaction(const JSONRPCRequest& request)
             "1. \"inputs\"                (array, required) A json array of json objects\n"
             "     [\n"
             "       {\n"
-            "         \"txid\":\"id\",    (string, required) The transaction id\n"
+            "         \"txid\":\"id\",      (string, required) The transaction id\n"
             "         \"vout\":n,         (numeric, required) The output number\n"
             "         \"sequence\":n      (numeric, optional) The sequence number\n"
             "       } \n"
             "       ,...\n"
             "     ]\n"
-            "2. \"outputs\"               (object, required) a json object with outputs\n"
+            "2. \"outputs\"               (array, required) a json array with outputs (key-value pairs)\n"
+            "   [\n"
             "    {\n"
-            "      \"address\": x.xxx,    (numeric or string, required) The key is the bitcoin address, the numeric value (can be string) is the " + CURRENCY_UNIT + " amount\n"
-            "      \"data\": \"hex\"      (string, required) The key is \"data\", the value is hex encoded data\n"
-            "      ,...\n"
+            "      \"address\": x.xxx,    (obj, optional) A key-value pair. The key (string) is the bitcoin address, the value (float or string) is the amount in " + CURRENCY_UNIT + "\n"
+            "    },\n"
+            "    {\n"
+            "      \"data\": \"hex\"        (obj, optional) A key-value pair. The key must be \"data\", the value is hex encoded data\n"
             "    }\n"
+            "    ,...                     More key-value pairs of the above form. For compatibility reasons, a dictionary, which holds the key-value pairs directly, is also\n"
+            "                             accepted as second parameter.\n"
+            "   ]\n"
             "3. locktime                  (numeric, optional, default=0) Raw locktime. Non-0 value also locktime-activates inputs\n"
             "4. replaceable               (boolean, optional, default=false) Marks this transaction as BIP125 replaceable.\n"
             "                             Allows this transaction to be replaced by a transaction with higher fees. If provided, it is an error if explicit sequence numbers are incompatible.\n"
@@ -348,18 +354,29 @@ UniValue createrawtransaction(const JSONRPCRequest& request)
             "\"transaction\"              (string) hex string of the transaction\n"
 
             "\nExamples:\n"
-            + HelpExampleCli("createrawtransaction", "\"[{\\\"txid\\\":\\\"myid\\\",\\\"vout\\\":0}]\" \"{\\\"address\\\":0.01}\"")
-            + HelpExampleCli("createrawtransaction", "\"[{\\\"txid\\\":\\\"myid\\\",\\\"vout\\\":0}]\" \"{\\\"data\\\":\\\"00010203\\\"}\"")
-            + HelpExampleRpc("createrawtransaction", "\"[{\\\"txid\\\":\\\"myid\\\",\\\"vout\\\":0}]\", \"{\\\"address\\\":0.01}\"")
-            + HelpExampleRpc("createrawtransaction", "\"[{\\\"txid\\\":\\\"myid\\\",\\\"vout\\\":0}]\", \"{\\\"data\\\":\\\"00010203\\\"}\"")
+            + HelpExampleCli("createrawtransaction", "\"[{\\\"txid\\\":\\\"myid\\\",\\\"vout\\\":0}]\" \"[{\\\"address\\\":0.01}]\"")
+            + HelpExampleCli("createrawtransaction", "\"[{\\\"txid\\\":\\\"myid\\\",\\\"vout\\\":0}]\" \"[{\\\"data\\\":\\\"00010203\\\"}]\"")
+            + HelpExampleRpc("createrawtransaction", "\"[{\\\"txid\\\":\\\"myid\\\",\\\"vout\\\":0}]\", \"[{\\\"address\\\":0.01}]\"")
+            + HelpExampleRpc("createrawtransaction", "\"[{\\\"txid\\\":\\\"myid\\\",\\\"vout\\\":0}]\", \"[{\\\"data\\\":\\\"00010203\\\"}]\"")
+            // clang-format on
         );
+    }
 
-    RPCTypeCheck(request.params, {UniValue::VARR, UniValue::VOBJ, UniValue::VNUM, UniValue::VBOOL}, true);
+    RPCTypeCheck(request.params, {
+        UniValue::VARR,
+        UniValueType(), // ARR or OBJ, checked later
+        UniValue::VNUM,
+        UniValue::VBOOL
+        }, true
+    );
     if (request.params[0].isNull() || request.params[1].isNull())
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, arguments 1 and 2 must be non-null");
 
     UniValue inputs = request.params[0].get_array();
-    UniValue sendTo = request.params[1].get_obj();
+    const bool outputs_is_obj = request.params[1].isObject();
+    UniValue outputs = outputs_is_obj ?
+                           request.params[1].get_obj() :
+                           request.params[1].get_array();
 
     CMutableTransaction rawTx;
 
@@ -411,11 +428,24 @@ UniValue createrawtransaction(const JSONRPCRequest& request)
     }
 
     std::set<CTxDestination> destinations;
-    std::vector<std::string> addrList = sendTo.getKeys();
-    for (const std::string& name_ : addrList) {
-
+    if (!outputs_is_obj) {
+        // Translate array of key-value pairs into dict
+        UniValue outputs_dict = UniValue(UniValue::VOBJ);
+        for (size_t i = 0; i < outputs.size(); ++i) {
+            const UniValue& output = outputs[i];
+            if (!output.isObject()) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, key-value pair not an object as expected");
+            }
+            if (output.size() != 1) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, key-value pair must contain exactly one key");
+            }
+            outputs_dict.pushKVs(output);
+        }
+        outputs = std::move(outputs_dict);
+    }
+    for (const std::string& name_ : outputs.getKeys()) {
         if (name_ == "data") {
-            std::vector<unsigned char> data = ParseHexV(sendTo[name_].getValStr(),"Data");
+            std::vector<unsigned char> data = ParseHexV(outputs[name_].getValStr(), "Data");
 
             CTxOut out(0, CScript() << OP_RETURN << data);
             rawTx.vout.push_back(out);
@@ -430,7 +460,7 @@ UniValue createrawtransaction(const JSONRPCRequest& request)
             }
 
             CScript scriptPubKey = GetScriptForDestination(destination);
-            CAmount nAmount = AmountFromValue(sendTo[name_]);
+            CAmount nAmount = AmountFromValue(outputs[name_]);
 
             CTxOut out(nAmount, scriptPubKey);
             rawTx.vout.push_back(out);
diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index 35401bf876..54995ef000 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -50,12 +50,11 @@ void RPCServer::OnStopped(std::function<void ()> slot)
 }
 
 void RPCTypeCheck(const UniValue& params,
-                  const std::list<UniValue::VType>& typesExpected,
+                  const std::list<UniValueType>& typesExpected,
                   bool fAllowNull)
 {
     unsigned int i = 0;
-    for (UniValue::VType t : typesExpected)
-    {
+    for (const UniValueType& t : typesExpected) {
         if (params.size() <= i)
             break;
 
@@ -67,10 +66,10 @@ void RPCTypeCheck(const UniValue& params,
     }
 }
 
-void RPCTypeCheckArgument(const UniValue& value, UniValue::VType typeExpected)
+void RPCTypeCheckArgument(const UniValue& value, const UniValueType& typeExpected)
 {
-    if (value.type() != typeExpected) {
-        throw JSONRPCError(RPC_TYPE_ERROR, strprintf("Expected type %s, got %s", uvTypeName(typeExpected), uvTypeName(value.type())));
+    if (!typeExpected.typeAny && value.type() != typeExpected.type) {
+        throw JSONRPCError(RPC_TYPE_ERROR, strprintf("Expected type %s, got %s", uvTypeName(typeExpected.type), uvTypeName(value.type())));
     }
 }
 
diff --git a/src/rpc/server.h b/src/rpc/server.h
index 075940cb90..8b32924fbc 100644
--- a/src/rpc/server.h
+++ b/src/rpc/server.h
@@ -28,9 +28,9 @@ namespace RPCServer
 }
 
 /** Wrapper for UniValue::VType, which includes typeAny:
- * Used to denote don't care type. Only used by RPCTypeCheckObj */
+ * Used to denote don't care type. */
 struct UniValueType {
-    explicit UniValueType(UniValue::VType _type) : typeAny(false), type(_type) {}
+    UniValueType(UniValue::VType _type) : typeAny(false), type(_type) {}
     UniValueType() : typeAny(true) {}
     bool typeAny;
     UniValue::VType type;
@@ -69,12 +69,12 @@ bool RPCIsInWarmup(std::string *outStatus);
  * the right number of arguments are passed, just that any passed are the correct type.
  */
 void RPCTypeCheck(const UniValue& params,
-                  const std::list<UniValue::VType>& typesExpected, bool fAllowNull=false);
+                  const std::list<UniValueType>& typesExpected, bool fAllowNull=false);
 
 /**
  * Type-check one argument; throws JSONRPCError if wrong type given.
  */
-void RPCTypeCheckArgument(const UniValue& value, UniValue::VType typeExpected);
+void RPCTypeCheckArgument(const UniValue& value, const UniValueType& typeExpected);
 
 /*
   Check for expected keys/value types in an Object.
diff --git a/src/test/rpc_tests.cpp b/src/test/rpc_tests.cpp
index 892e4f2dac..8d9f80ada0 100644
--- a/src/test/rpc_tests.cpp
+++ b/src/test/rpc_tests.cpp
@@ -52,7 +52,6 @@ BOOST_AUTO_TEST_CASE(rpc_rawparams)
     BOOST_CHECK_THROW(CallRPC("createrawtransaction"), std::runtime_error);
     BOOST_CHECK_THROW(CallRPC("createrawtransaction null null"), std::runtime_error);
     BOOST_CHECK_THROW(CallRPC("createrawtransaction not_array"), std::runtime_error);
-    BOOST_CHECK_THROW(CallRPC("createrawtransaction [] []"), std::runtime_error);
     BOOST_CHECK_THROW(CallRPC("createrawtransaction {} {}"), std::runtime_error);
     BOOST_CHECK_NO_THROW(CallRPC("createrawtransaction [] {}"));
     BOOST_CHECK_THROW(CallRPC("createrawtransaction [] {} extra"), std::runtime_error);