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

6 files changed, 111 insertions, 42 deletions

diff --git a/doc/release-notes.md b/doc/release-notes.md
index d08e2518c7..a79012722f 100644
--- a/doc/release-notes.md
+++ b/doc/release-notes.md
@@ -61,7 +61,8 @@ RPC changes
 
 ### Low-level changes
 
-- The `fundrawtransaction` rpc will reject the previously deprecated `reserveChangeKey` option.
+- The `createrawtransaction` RPC will now accept an array or dictionary (kept for compatibility) for the `outputs` parameter. This means the order of transaction outputs can be specified by the client.
+- The `fundrawtransaction` RPC will reject the previously deprecated `reserveChangeKey` option.
 
 External wallet files
 ---------------------
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);
diff --git a/test/functional/rpc_rawtransaction.py b/test/functional/rpc_rawtransaction.py
index e074f5bd74..825b897871 100755
--- a/test/functional/rpc_rawtransaction.py
+++ b/test/functional/rpc_rawtransaction.py
@@ -12,7 +12,12 @@ Test the following RPCs:
    - getrawtransaction
 """
 
+from collections import OrderedDict
+from io import BytesIO
 from test_framework.test_framework import BitcoinTestFramework
+from test_framework.messages import (
+    CTransaction,
+)
 from test_framework.util import *
 
 
@@ -43,11 +48,10 @@ class RawTransactionsTest(BitcoinTestFramework):
 
     def setup_network(self, split=False):
         super().setup_network()
-        connect_nodes_bi(self.nodes,0,2)
+        connect_nodes_bi(self.nodes, 0, 2)
 
     def run_test(self):
-
-        #prepare some coins for multiple *rawtransaction commands
+        self.log.info('prepare some coins for multiple *rawtransaction commands')
         self.nodes[2].generate(1)
         self.sync_all()
         self.nodes[0].generate(101)
@@ -59,10 +63,11 @@ class RawTransactionsTest(BitcoinTestFramework):
         self.nodes[0].generate(5)
         self.sync_all()
 
-        # Test getrawtransaction on genesis block coinbase returns an error
+        self.log.info('Test getrawtransaction on genesis block coinbase returns an error')
         block = self.nodes[0].getblock(self.nodes[0].getblockhash(0))
         assert_raises_rpc_error(-5, "The genesis block coinbase is not considered an ordinary transaction", self.nodes[0].getrawtransaction, block['merkleroot'])
 
+        self.log.info('Check parameter types and required parameters of createrawtransaction')
         # Test `createrawtransaction` required parameters
         assert_raises_rpc_error(-1, "createrawtransaction", self.nodes[0].createrawtransaction)
         assert_raises_rpc_error(-1, "createrawtransaction", self.nodes[0].createrawtransaction, [])
@@ -83,12 +88,18 @@ class RawTransactionsTest(BitcoinTestFramework):
 
         # Test `createrawtransaction` invalid `outputs`
         address = self.nodes[0].getnewaddress()
-        assert_raises_rpc_error(-3, "Expected type object", self.nodes[0].createrawtransaction, [], 'foo')
+        address2 = self.nodes[0].getnewaddress()
+        assert_raises_rpc_error(-1, "JSON value is not an array as expected", self.nodes[0].createrawtransaction, [], 'foo')
+        self.nodes[0].createrawtransaction(inputs=[], outputs={})  # Should not throw for backwards compatibility
+        self.nodes[0].createrawtransaction(inputs=[], outputs=[])
         assert_raises_rpc_error(-8, "Data must be hexadecimal string", self.nodes[0].createrawtransaction, [], {'data': 'foo'})
         assert_raises_rpc_error(-5, "Invalid Bitcoin address", self.nodes[0].createrawtransaction, [], {'foo': 0})
         assert_raises_rpc_error(-3, "Invalid amount", self.nodes[0].createrawtransaction, [], {address: 'foo'})
         assert_raises_rpc_error(-3, "Amount out of range", self.nodes[0].createrawtransaction, [], {address: -1})
         assert_raises_rpc_error(-8, "Invalid parameter, duplicated address: %s" % address, self.nodes[0].createrawtransaction, [], multidict([(address, 1), (address, 1)]))
+        assert_raises_rpc_error(-8, "Invalid parameter, duplicated address: %s" % address, self.nodes[0].createrawtransaction, [], [{address: 1}, {address: 1}])
+        assert_raises_rpc_error(-8, "Invalid parameter, key-value pair must contain exactly one key", self.nodes[0].createrawtransaction, [], [{'a': 1, 'b': 2}])
+        assert_raises_rpc_error(-8, "Invalid parameter, key-value pair not an object as expected", self.nodes[0].createrawtransaction, [], [['key-value pair1'], ['2']])
 
         # Test `createrawtransaction` invalid `locktime`
         assert_raises_rpc_error(-3, "Expected type number", self.nodes[0].createrawtransaction, [], {}, 'foo')
@@ -98,9 +109,38 @@ class RawTransactionsTest(BitcoinTestFramework):
         # Test `createrawtransaction` invalid `replaceable`
         assert_raises_rpc_error(-3, "Expected type bool", self.nodes[0].createrawtransaction, [], {}, 0, 'foo')
 
-        #########################################
-        # sendrawtransaction with missing input #
-        #########################################
+        self.log.info('Check that createrawtransaction accepts an array and object as outputs')
+        tx = CTransaction()
+        # One output
+        tx.deserialize(BytesIO(hex_str_to_bytes(self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs={address: 99}))))
+        assert_equal(len(tx.vout), 1)
+        assert_equal(
+            bytes_to_hex_str(tx.serialize()),
+            self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs=[{address: 99}]),
+        )
+        # Two outputs
+        tx.deserialize(BytesIO(hex_str_to_bytes(self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs=OrderedDict([(address, 99), (address2, 99)])))))
+        assert_equal(len(tx.vout), 2)
+        assert_equal(
+            bytes_to_hex_str(tx.serialize()),
+            self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs=[{address: 99}, {address2: 99}]),
+        )
+        # Two data outputs
+        tx.deserialize(BytesIO(hex_str_to_bytes(self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs=multidict([('data', '99'), ('data', '99')])))))
+        assert_equal(len(tx.vout), 2)
+        assert_equal(
+            bytes_to_hex_str(tx.serialize()),
+            self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs=[{'data': '99'}, {'data': '99'}]),
+        )
+        # Multiple mixed outputs
+        tx.deserialize(BytesIO(hex_str_to_bytes(self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs=multidict([(address, 99), ('data', '99'), ('data', '99')])))))
+        assert_equal(len(tx.vout), 3)
+        assert_equal(
+            bytes_to_hex_str(tx.serialize()),
+            self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs=[{address: 99}, {'data': '99'}, {'data': '99'}]),
+        )
+
+        self.log.info('sendrawtransaction with missing input')
         inputs  = [ {'txid' : "1d1d4e24ed99057e84c3f80fd8fbec79ed9e1acee37da269356ecea000000000", 'vout' : 1}] #won't exists
         outputs = { self.nodes[0].getnewaddress() : 4.998 }
         rawtx   = self.nodes[2].createrawtransaction(inputs, outputs)
@@ -248,14 +288,14 @@ class RawTransactionsTest(BitcoinTestFramework):
         outputs = { self.nodes[0].getnewaddress() : 2.19 }
         rawTx2 = self.nodes[2].createrawtransaction(inputs, outputs)
         rawTxPartialSigned1 = self.nodes[1].signrawtransactionwithwallet(rawTx2, inputs)
-        self.log.info(rawTxPartialSigned1)
+        self.log.debug(rawTxPartialSigned1)
         assert_equal(rawTxPartialSigned['complete'], False) #node1 only has one key, can't comp. sign the tx
 
         rawTxPartialSigned2 = self.nodes[2].signrawtransactionwithwallet(rawTx2, inputs)
-        self.log.info(rawTxPartialSigned2)
+        self.log.debug(rawTxPartialSigned2)
         assert_equal(rawTxPartialSigned2['complete'], False) #node2 only has one key, can't comp. sign the tx
         rawTxComb = self.nodes[2].combinerawtransaction([rawTxPartialSigned1['hex'], rawTxPartialSigned2['hex']])
-        self.log.info(rawTxComb)
+        self.log.debug(rawTxComb)
         self.nodes[2].sendrawtransaction(rawTxComb)
         rawTx2 = self.nodes[0].decoderawtransaction(rawTxComb)
         self.sync_all()
@@ -273,7 +313,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         encrawtx = "01000000010000000000000072c1a6a246ae63f74f931e8365e15a089c68d61900000000000000000000ffffffff0100e1f505000000000000000000"
         decrawtx = self.nodes[0].decoderawtransaction(encrawtx, False) # decode as non-witness transaction
         assert_equal(decrawtx['vout'][0]['value'], Decimal('1.00000000'))
-        
+
         # getrawtransaction tests
         # 1. valid parameters - only supply txid
         txHash = rawTx["hash"]