rpc, tests: Tests for retrieving RPC parameters by name

src/rpc/request.cpp

@@ -196,15 +196,13 @@ void JSONRPCRequest::parse(const UniValue& valRequest)
 const UniValue& JSONRPCRequest::JSONRPCParameters::operator[](const std::string& key) const
 {
     const auto it = named.find(key);
-    Assert(it != named.end());
+    if (it == named.end()) return NullUniValue;
     return *it->second;
 }
 
 const UniValue& JSONRPCRequest::JSONRPCParameters::operator[](size_t pos) const
 {
-    if (pos >= positional.size()) {
-        return NullUniValue;
-    }
+    if (pos >= positional.size()) return NullUniValue;
     const UniValue* item = positional.at(pos);
     return item ? *item : NullUniValue;
 }

src/rpc/request.h

@@ -34,8 +34,7 @@ class JSONRPCRequest
     public:
         /** The parameters as received */
         UniValue received;
-        /** Parameter name to parameter. All parameters will be present,
-         * those not provided at all (neither named nor positional) will be stored as NullUniValue */
+        /** Parameter name to parameter. Only provided parameters will be present. */
         std::unordered_map<std::string, const UniValue*> named;
         /** Parameter position to parameter.
          * Parameters not provided at all (neither named nor positional) will be stored as nullptr,
@@ -46,9 +45,9 @@ class JSONRPCRequest
         /** Process the received parameters into named and positional mappings */
         void ProcessParameters(const std::vector<std::string>& argNames);
 
-        /** Retrieve a parameter by its name */
+        /** Retrieve a parameter by its name. Unknown parameters are returned as NullUniValue. */
         const UniValue& operator[](const std::string& key) const;
-        /** Retrieve a parameter by its position */
+        /** Retrieve a parameter by its position. Out of bound parameters are returned as NullUniValue */
         const UniValue& operator[](size_t pos) const;
 
         /** The number of parameters received */

src/test/rpc_tests.cpp

@@ -88,6 +88,7 @@ BOOST_AUTO_TEST_CASE(rpc_namedparams)
 
     // Make sure named arguments are transformed into positional arguments in correct places separated by nulls
     BOOST_CHECK_EQUAL(TransformParams(JSON(R"({"arg2": 2, "arg4": 4})"), arg_names).write(), "[null,2,null,4]");
+    BOOST_CHECK_EQUAL(TransformParams(JSON(R"({"arg2": 2, "arg4": 4, "arg5": null})"), arg_names).write(), "[null,2,null,4,null]");
 
     // Make sure named argument specified multiple times raises an exception
     BOOST_CHECK_EXCEPTION(TransformParams(JSON(R"({"arg2": 2, "arg2": 4})"), arg_names), UniValue,
@@ -541,4 +542,49 @@ BOOST_AUTO_TEST_CASE(help_example)
     BOOST_CHECK_NE(HelpExampleRpcNamed("foo", {{"arg", true}}), HelpExampleRpcNamed("foo", {{"arg", "true"}}));
 }
 
+static void TestParamsByName(const UniValue& params)
+{
+    const std::vector<std::string> arg_names{"arg0", "arg1", "arg2", "arg3", "arg4", "arg5"};
+    CRPCTable table;
+    CRPCCommand command{"category", "method",
+        [&](const JSONRPCRequest& request, UniValue&, bool) -> bool
+        {
+            for (size_t i = 0; i < request.params.size() * 2; ++i) {
+                std::string arg_name = strprintf("arg%u", i);
+                if (i < arg_names.size()) {
+                    // Known parameters should be the same for both positional and named
+                    BOOST_CHECK_EQUAL(request.params[arg_name].getType(), request.params[i].getType());
+                    BOOST_CHECK_EQUAL(request.params[arg_name].getValStr(), request.params[i].getValStr());
+                } else {
+                    // Unknown positionals should still be accessible
+                    auto arg = request.params[i];
+                    if (i > request.params.size()) {
+                        // Out of bound positionals are always NullUniValue
+                        BOOST_CHECK(arg.isNull());
+                    }
+                    // Unknown named are always NullUniValue
+                    BOOST_CHECK(request.params[arg_name].isNull());
+                }
+            }
+            return true;
+        },
+        arg_names,
+        /*unique_id=*/0
+    };
+    table.appendCommand("method", &command);
+    JSONRPCRequest request;
+    request.strMethod = "method";
+    request.params.received = params;
+    if (RPCIsInWarmup(nullptr)) SetRPCWarmupFinished();
+    table.execute(request);
+}
+
+BOOST_AUTO_TEST_CASE(rpc_params_by_name)
+{
+    TestParamsByName(JSON(R"({"arg2": 2, "arg4": 4})"));
+    TestParamsByName(JSON(R"({"arg2": 2, "arg4": 4, "arg5": null})"));
+    TestParamsByName(JSON(R"([1, 2, 3, 4, 5, 6, 7, 8])"));
+    TestParamsByName(JSON(R"({"args": [1, 2, 3], "arg5": 5})"));
+}
+
 BOOST_AUTO_TEST_SUITE_END()