diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index 5ec93666d..fd53eced6 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -1,576 +1,574 @@
 // Copyright (c) 2010 Satoshi Nakamoto
 // Copyright (c) 2009-2018 The Bitcoin Core developers
 // Copyright (c) 2018-2019 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <rpc/server.h>
 
 #include <config.h>
 #include <rpc/util.h>
 #include <shutdown.h>
 #include <sync.h>
 #include <util/strencodings.h>
 
 #include <boost/algorithm/string/classification.hpp>
 #include <boost/algorithm/string/split.hpp>
 #include <boost/signals2/signal.hpp>
 
 #include <cassert>
 #include <memory> // for unique_ptr
 #include <mutex>
 #include <set>
 #include <unordered_map>
 
 static Mutex g_rpc_warmup_mutex;
 static std::atomic<bool> g_rpc_running{false};
 static bool fRPCInWarmup GUARDED_BY(g_rpc_warmup_mutex) = true;
 static std::string
     rpcWarmupStatus GUARDED_BY(g_rpc_warmup_mutex) = "RPC server started";
 /* Timer-creating functions */
 static RPCTimerInterface *timerInterface = nullptr;
 /* Map of name to timer. */
 static Mutex g_deadline_timers_mutex;
 static std::map<std::string, std::unique_ptr<RPCTimerBase>>
     deadlineTimers GUARDED_BY(g_deadline_timers_mutex);
 static bool ExecuteCommand(const Config &config, const CRPCCommand &command,
                            const JSONRPCRequest &request, UniValue &result,
                            bool last_handler);
 
 struct RPCCommandExecutionInfo {
     std::string method;
     int64_t start;
 };
 
 struct RPCServerInfo {
     Mutex mutex;
     std::list<RPCCommandExecutionInfo> active_commands GUARDED_BY(mutex);
 };
 
 static RPCServerInfo g_rpc_server_info;
 
 struct RPCCommandExecution {
     std::list<RPCCommandExecutionInfo>::iterator it;
     explicit RPCCommandExecution(const std::string &method) {
         LOCK(g_rpc_server_info.mutex);
         it = g_rpc_server_info.active_commands.insert(
             g_rpc_server_info.active_commands.cend(),
             {method, GetTimeMicros()});
     }
     ~RPCCommandExecution() {
         LOCK(g_rpc_server_info.mutex);
         g_rpc_server_info.active_commands.erase(it);
     }
 };
 
 UniValue RPCServer::ExecuteCommand(const Config &config,
                                    const JSONRPCRequest &request) const {
     // Return immediately if in warmup
     // This is retained from the old RPC implementation because a lot of state
     // is set during warmup that RPC commands may depend on.  This can be
     // safely removed once global variable usage has been eliminated.
     {
         LOCK(g_rpc_warmup_mutex);
         if (fRPCInWarmup) {
             throw JSONRPCError(RPC_IN_WARMUP, rpcWarmupStatus);
         }
     }
 
     std::string commandName = request.strMethod;
     {
         auto commandsReadView = commands.getReadView();
         auto iter = commandsReadView->find(commandName);
         if (iter != commandsReadView.end()) {
             return iter->second.get()->Execute(request);
         }
     }
 
     // TODO Remove the below call to tableRPC.execute() and only call it for
     // context-free RPC commands via an implementation of RPCCommand.
 
     // Check if context-free RPC method is valid and execute it
     return tableRPC.execute(config, request);
 }
 
 void RPCServer::RegisterCommand(std::unique_ptr<RPCCommand> command) {
     if (command != nullptr) {
         const std::string &commandName = command->GetName();
         commands.getWriteView()->insert(
             std::make_pair(commandName, std::move(command)));
     }
 }
 
 static struct CRPCSignals {
     boost::signals2::signal<void()> Started;
     boost::signals2::signal<void()> Stopped;
 } g_rpcSignals;
 
 void RPCServerSignals::OnStarted(std::function<void()> slot) {
     g_rpcSignals.Started.connect(slot);
 }
 
 void RPCServerSignals::OnStopped(std::function<void()> slot) {
     g_rpcSignals.Stopped.connect(slot);
 }
 
 std::string CRPCTable::help(const Config &config, const std::string &strCommand,
                             const JSONRPCRequest &helpreq) const {
     std::string strRet;
     std::string category;
     std::set<intptr_t> setDone;
     std::vector<std::pair<std::string, const CRPCCommand *>> vCommands;
 
     for (const auto &entry : mapCommands) {
         vCommands.push_back(
             std::make_pair(entry.second.front()->category + entry.first,
                            entry.second.front()));
     }
     sort(vCommands.begin(), vCommands.end());
 
     JSONRPCRequest jreq(helpreq);
     jreq.fHelp = true;
     jreq.params = UniValue();
 
     for (const std::pair<std::string, const CRPCCommand *> &command :
          vCommands) {
         const CRPCCommand *pcmd = command.second;
         std::string strMethod = pcmd->name;
         if ((strCommand != "" || pcmd->category == "hidden") &&
             strMethod != strCommand) {
             continue;
         }
 
         jreq.strMethod = strMethod;
         try {
             UniValue unused_result;
             if (setDone.insert(pcmd->unique_id).second) {
                 pcmd->actor(config, jreq, unused_result,
                             true /* last_handler */);
             }
         } catch (const std::exception &e) {
             // Help text is returned in an exception
             std::string strHelp = std::string(e.what());
             if (strCommand == "") {
                 if (strHelp.find('\n') != std::string::npos) {
                     strHelp = strHelp.substr(0, strHelp.find('\n'));
                 }
 
                 if (category != pcmd->category) {
                     if (!category.empty()) {
                         strRet += "\n";
                     }
                     category = pcmd->category;
                     strRet += "== " + Capitalize(category) + " ==\n";
                 }
             }
             strRet += strHelp + "\n";
         }
     }
     if (strRet == "") {
         strRet = strprintf("help: unknown command: %s\n", strCommand);
     }
 
     strRet = strRet.substr(0, strRet.size() - 1);
     return strRet;
 }
 
 static RPCHelpMan help() {
     return RPCHelpMan{
         "help",
         "List all commands, or get help for a specified command.\n",
         {
             {"command", RPCArg::Type::STR, /* default */ "all commands",
              "The command to get help on"},
         },
         RPCResult{RPCResult::Type::STR, "", "The help text"},
         RPCExamples{""},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &jsonRequest) -> UniValue {
             std::string strCommand;
             if (jsonRequest.params.size() > 0) {
                 strCommand = jsonRequest.params[0].get_str();
             }
 
             return tableRPC.help(config, strCommand, jsonRequest);
         },
     };
 }
 
 static RPCHelpMan stop() {
     static const std::string RESULT{PACKAGE_NAME " stopping"};
     return RPCHelpMan{
         "stop",
         // Also accept the hidden 'wait' integer argument (milliseconds)
         // For instance, 'stop 1000' makes the call wait 1 second before
         // returning to the client (intended for testing)
         "\nRequest a graceful shutdown of " PACKAGE_NAME ".",
         {
             {"wait",
              RPCArg::Type::NUM,
              RPCArg::Optional::OMITTED_NAMED_ARG,
              "how long to wait in ms",
              "",
              {},
              /* hidden */ true},
         },
         RPCResult{RPCResult::Type::STR, "",
                   "A string with the content '" + RESULT + "'"},
         RPCExamples{""},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &jsonRequest) -> UniValue {
             // Event loop will exit after current HTTP requests have been
             // handled, so this reply will get back to the client.
             StartShutdown();
             if (jsonRequest.params[0].isNum()) {
                 UninterruptibleSleep(
                     std::chrono::milliseconds{jsonRequest.params[0].get_int()});
             }
             return RESULT;
         },
     };
 }
 
 static RPCHelpMan uptime() {
     return RPCHelpMan{
         "uptime",
         "Returns the total uptime of the server.\n",
         {},
         RPCResult{RPCResult::Type::NUM, "",
                   "The number of seconds that the server has been running"},
         RPCExamples{HelpExampleCli("uptime", "") +
                     HelpExampleRpc("uptime", "")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             return GetTime() - GetStartupTime();
         }};
 }
 
 static RPCHelpMan getrpcinfo() {
     return RPCHelpMan{
         "getrpcinfo",
         "Returns details of the RPC server.\n",
         {},
         RPCResult{RPCResult::Type::OBJ,
                   "",
                   "",
                   {
                       {RPCResult::Type::ARR,
                        "active_commands",
                        "All active commands",
                        {
                            {RPCResult::Type::OBJ,
                             "",
                             "Information about an active command",
                             {
                                 {RPCResult::Type::STR, "method",
                                  "The name of the RPC command"},
                                 {RPCResult::Type::NUM, "duration",
                                  "The running time in microseconds"},
                             }},
                        }},
                       {RPCResult::Type::STR, "logpath",
                        "The complete file path to the debug log"},
                   }},
         RPCExamples{HelpExampleCli("getrpcinfo", "") +
                     HelpExampleRpc("getrpcinfo", "")},
 
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             LOCK(g_rpc_server_info.mutex);
             UniValue active_commands(UniValue::VARR);
             for (const RPCCommandExecutionInfo &info :
                  g_rpc_server_info.active_commands) {
                 UniValue entry(UniValue::VOBJ);
                 entry.pushKV("method", info.method);
                 entry.pushKV("duration", GetTimeMicros() - info.start);
                 active_commands.push_back(entry);
             }
 
             UniValue result(UniValue::VOBJ);
             result.pushKV("active_commands", active_commands);
 
             const std::string path = LogInstance().m_file_path.string();
             UniValue log_path(UniValue::VSTR, path);
             result.pushKV("logpath", log_path);
 
             return result;
         }};
 }
 
 // clang-format off
 static const CRPCCommand vRPCCommands[] = {
     //  category            name                      actor (function)        argNames
     //  ------------------- ------------------------  ----------------------  ----------
     /* Overall control/query calls */
     { "control",            "getrpcinfo",             getrpcinfo,             {}  },
     { "control",            "help",                   help,                   {"command"}  },
     { "control",            "stop",                   stop,                   {"wait"}  },
     { "control",            "uptime",                 uptime,                 {}  },
 };
 // clang-format on
 
 CRPCTable::CRPCTable() {
     for (const auto &c : vRPCCommands) {
         appendCommand(c.name, &c);
     }
 }
 
-bool CRPCTable::appendCommand(const std::string &name,
+void CRPCTable::appendCommand(const std::string &name,
                               const CRPCCommand *pcmd) {
-    if (IsRPCRunning()) {
-        return false;
-    }
+    // Only add commands before rpc is running
+    CHECK_NONFATAL(!IsRPCRunning());
 
     mapCommands[name].push_back(pcmd);
-    return true;
 }
 
 bool CRPCTable::removeCommand(const std::string &name,
                               const CRPCCommand *pcmd) {
     auto it = mapCommands.find(name);
     if (it != mapCommands.end()) {
         auto new_end = std::remove(it->second.begin(), it->second.end(), pcmd);
         if (it->second.end() != new_end) {
             it->second.erase(new_end, it->second.end());
             return true;
         }
     }
     return false;
 }
 
 void StartRPC() {
     LogPrint(BCLog::RPC, "Starting RPC\n");
     g_rpc_running = true;
     g_rpcSignals.Started();
 }
 
 void InterruptRPC() {
     static std::once_flag g_rpc_interrupt_flag;
     // This function could be called twice if the GUI has been started with
     // -server=1.
     std::call_once(g_rpc_interrupt_flag, []() {
         LogPrint(BCLog::RPC, "Interrupting RPC\n");
         // Interrupt e.g. running longpolls
         g_rpc_running = false;
     });
 }
 
 void StopRPC() {
     static std::once_flag g_rpc_stop_flag;
     // This function could be called twice if the GUI has been started with
     // -server=1.
     assert(!g_rpc_running);
     std::call_once(g_rpc_stop_flag, []() {
         LogPrint(BCLog::RPC, "Stopping RPC\n");
         WITH_LOCK(g_deadline_timers_mutex, deadlineTimers.clear());
         DeleteAuthCookie();
         g_rpcSignals.Stopped();
     });
 }
 
 bool IsRPCRunning() {
     return g_rpc_running;
 }
 
 void RpcInterruptionPoint() {
     if (!IsRPCRunning()) {
         throw JSONRPCError(RPC_CLIENT_NOT_CONNECTED, "Shutting down");
     }
 }
 
 void SetRPCWarmupStatus(const std::string &newStatus) {
     LOCK(g_rpc_warmup_mutex);
     rpcWarmupStatus = newStatus;
 }
 
 void SetRPCWarmupFinished() {
     LOCK(g_rpc_warmup_mutex);
     assert(fRPCInWarmup);
     fRPCInWarmup = false;
 }
 
 bool RPCIsInWarmup(std::string *outStatus) {
     LOCK(g_rpc_warmup_mutex);
     if (outStatus) {
         *outStatus = rpcWarmupStatus;
     }
     return fRPCInWarmup;
 }
 
 bool IsDeprecatedRPCEnabled(const ArgsManager &args,
                             const std::string &method) {
     const std::vector<std::string> enabled_methods =
         args.GetArgs("-deprecatedrpc");
 
     return find(enabled_methods.begin(), enabled_methods.end(), method) !=
            enabled_methods.end();
 }
 
 static UniValue JSONRPCExecOne(const Config &config, RPCServer &rpcServer,
                                JSONRPCRequest jreq, const UniValue &req) {
     UniValue rpc_result(UniValue::VOBJ);
 
     try {
         jreq.parse(req);
 
         UniValue result = rpcServer.ExecuteCommand(config, jreq);
         rpc_result = JSONRPCReplyObj(result, NullUniValue, jreq.id);
     } catch (const UniValue &objError) {
         rpc_result = JSONRPCReplyObj(NullUniValue, objError, jreq.id);
     } catch (const std::exception &e) {
         rpc_result = JSONRPCReplyObj(
             NullUniValue, JSONRPCError(RPC_PARSE_ERROR, e.what()), jreq.id);
     }
 
     return rpc_result;
 }
 
 std::string JSONRPCExecBatch(const Config &config, RPCServer &rpcServer,
                              const JSONRPCRequest &jreq, const UniValue &vReq) {
     UniValue ret(UniValue::VARR);
     for (size_t i = 0; i < vReq.size(); i++) {
         ret.push_back(JSONRPCExecOne(config, rpcServer, jreq, vReq[i]));
     }
 
     return ret.write() + "\n";
 }
 
 /**
  * Process named arguments into a vector of positional arguments, based on the
  * passed-in specification for the RPC call's arguments.
  */
 static inline JSONRPCRequest
 transformNamedArguments(const JSONRPCRequest &in,
                         const std::vector<std::string> &argNames) {
     JSONRPCRequest out = in;
     out.params = UniValue(UniValue::VARR);
     // Build a map of parameters, and remove ones that have been processed, so
     // that we can throw a focused error if there is an unknown one.
     const std::vector<std::string> &keys = in.params.getKeys();
     const std::vector<UniValue> &values = in.params.getValues();
     std::unordered_map<std::string, const UniValue *> argsIn;
     for (size_t i = 0; i < keys.size(); ++i) {
         argsIn[keys[i]] = &values[i];
     }
     // Process expected parameters.
     int hole = 0;
     for (const std::string &argNamePattern : argNames) {
         std::vector<std::string> vargNames;
         boost::algorithm::split(vargNames, argNamePattern,
                                 boost::algorithm::is_any_of("|"));
         auto fr = argsIn.end();
         for (const std::string &argName : vargNames) {
             fr = argsIn.find(argName);
             if (fr != argsIn.end()) {
                 break;
             }
         }
         if (fr != argsIn.end()) {
             for (int i = 0; i < hole; ++i) {
                 // Fill hole between specified parameters with JSON nulls, but
                 // not at the end (for backwards compatibility with calls that
                 // act based on number of specified parameters).
                 out.params.push_back(UniValue());
             }
             hole = 0;
             out.params.push_back(*fr->second);
             argsIn.erase(fr);
         } else {
             hole += 1;
         }
     }
     // If there are still arguments in the argsIn map, this is an error.
     if (!argsIn.empty()) {
         throw JSONRPCError(RPC_INVALID_PARAMETER,
                            "Unknown named parameter " + argsIn.begin()->first);
     }
     // Return request with named arguments transformed to positional arguments
     return out;
 }
 
 UniValue CRPCTable::execute(const Config &config,
                             const JSONRPCRequest &request) const {
     // Return immediately if in warmup
     {
         LOCK(g_rpc_warmup_mutex);
         if (fRPCInWarmup) {
             throw JSONRPCError(RPC_IN_WARMUP, rpcWarmupStatus);
         }
     }
 
     // Find method
     auto it = mapCommands.find(request.strMethod);
     if (it != mapCommands.end()) {
         UniValue result;
         for (const auto &command : it->second) {
             if (ExecuteCommand(config, *command, request, result,
                                &command == &it->second.back())) {
                 return result;
             }
         }
     }
     throw JSONRPCError(RPC_METHOD_NOT_FOUND, "Method not found");
 }
 
 static bool ExecuteCommand(const Config &config, const CRPCCommand &command,
                            const JSONRPCRequest &request, UniValue &result,
                            bool last_handler) {
     try {
         RPCCommandExecution execution(request.strMethod);
         // Execute, convert arguments to array if necessary
         if (request.params.isObject()) {
             return command.actor(
                 config, transformNamedArguments(request, command.argNames),
                 result, last_handler);
         } else {
             return command.actor(config, request, result, last_handler);
         }
     } catch (const std::exception &e) {
         throw JSONRPCError(RPC_MISC_ERROR, e.what());
     }
 }
 
 std::vector<std::string> CRPCTable::listCommands() const {
     std::vector<std::string> commandList;
     for (const auto &i : mapCommands) {
         commandList.emplace_back(i.first);
     }
     return commandList;
 }
 
 void RPCSetTimerInterfaceIfUnset(RPCTimerInterface *iface) {
     if (!timerInterface) {
         timerInterface = iface;
     }
 }
 
 void RPCSetTimerInterface(RPCTimerInterface *iface) {
     timerInterface = iface;
 }
 
 void RPCUnsetTimerInterface(RPCTimerInterface *iface) {
     if (timerInterface == iface) {
         timerInterface = nullptr;
     }
 }
 
 void RPCRunLater(const std::string &name, std::function<void()> func,
                  int64_t nSeconds) {
     if (!timerInterface) {
         throw JSONRPCError(RPC_INTERNAL_ERROR,
                            "No timer handler registered for RPC");
     }
     LOCK(g_deadline_timers_mutex);
     deadlineTimers.erase(name);
     LogPrint(BCLog::RPC, "queue run of timer %s in %i seconds (using %s)\n",
              name, nSeconds, timerInterface->Name());
     deadlineTimers.emplace(
         name, std::unique_ptr<RPCTimerBase>(
                   timerInterface->NewTimer(func, nSeconds * 1000)));
 }
 
 int RPCSerializationFlags() {
     return 0;
 }
 
 CRPCTable tableRPC;
diff --git a/src/rpc/server.h b/src/rpc/server.h
index c2aa806ac..ab0fe992a 100644
--- a/src/rpc/server.h
+++ b/src/rpc/server.h
@@ -1,257 +1,256 @@
 // Copyright (c) 2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Copyright (c) 2017-2019 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_RPC_SERVER_H
 #define BITCOIN_RPC_SERVER_H
 
 #include <amount.h>
 #include <rpc/command.h>
 #include <rpc/request.h>
 #include <rpc/util.h>
 #include <rwcollection.h>
 #include <util/system.h>
 
 #include <univalue.h>
 
 #include <cstdint>
 #include <functional>
 #include <map>
 #include <string>
 
 static const unsigned int DEFAULT_RPC_SERIALIZE_VERSION = 1;
 
 class CRPCCommand;
 
 namespace RPCServerSignals {
 void OnStarted(std::function<void()> slot);
 void OnStopped(std::function<void()> slot);
 } // namespace RPCServerSignals
 
 class Config;
 
 typedef std::map<std::string, std::unique_ptr<RPCCommand>> RPCCommandMap;
 
 /**
  * Class for registering and managing all RPC calls.
  */
 class RPCServer {
 private:
     RWCollection<RPCCommandMap> commands;
 
 public:
     RPCServer() {}
 
     RPCServer(const RPCServer &) = delete;
     RPCServer &operator=(const RPCServer &) = delete;
 
     /**
      * Attempts to execute an RPC command from the given request.
      * If no RPC command exists that matches the request, an error is returned.
      */
     UniValue ExecuteCommand(const Config &config,
                             const JSONRPCRequest &request) const;
 
     /**
      * Register an RPC command.
      */
     void RegisterCommand(std::unique_ptr<RPCCommand> command);
 };
 
 /**
  * Query whether RPC is running
  */
 bool IsRPCRunning();
 
 /** Throw JSONRPCError if RPC is not running */
 void RpcInterruptionPoint();
 
 /**
  * Set the RPC warmup status.  When this is done, all RPC calls will error out
  * immediately with RPC_IN_WARMUP.
  */
 void SetRPCWarmupStatus(const std::string &newStatus);
 
 /**
  * Mark warmup as done.  RPC calls will be processed from now on.
  */
 void SetRPCWarmupFinished();
 
 /**
  * Returns the current warmup state
  */
 bool RPCIsInWarmup(std::string *outStatus);
 
 /**
  * Opaque base class for timers returned by NewTimerFunc.
  * This provides no methods at the moment, but makes sure that delete cleans up
  * the whole state.
  */
 class RPCTimerBase {
 public:
     virtual ~RPCTimerBase() {}
 };
 
 /**
  * RPC timer "driver".
  */
 class RPCTimerInterface {
 public:
     virtual ~RPCTimerInterface() {}
 
     /**
      * Implementation name
      */
     virtual const char *Name() = 0;
 
     /**
      * Factory function for timers.
      * RPC will call the function to create a timer that will call func in
      * *millis* milliseconds.
      * @note As the RPC mechanism is backend-neutral, it can use different
      * implementations of timers.
      * This is needed to cope with the case in which there is no HTTP server,
      * but only GUI RPC console, and to break the dependency of pcserver on
      * httprpc.
      */
     virtual RPCTimerBase *NewTimer(std::function<void()> &func,
                                    int64_t millis) = 0;
 };
 
 /**
  * Set the factory function for timers
  */
 void RPCSetTimerInterface(RPCTimerInterface *iface);
 
 /**
  * Set the factory function for timer, but only, if unset
  */
 void RPCSetTimerInterfaceIfUnset(RPCTimerInterface *iface);
 
 /**
  * Unset factory function for timers
  */
 void RPCUnsetTimerInterface(RPCTimerInterface *iface);
 
 /**
  * Run func nSeconds from now.
  * Overrides previous timer <name> (if any).
  */
 void RPCRunLater(const std::string &name, std::function<void()> func,
                  int64_t nSeconds);
 
 using rpcfn_type = UniValue (*)(const Config &config,
                                 const JSONRPCRequest &jsonRequest);
 using RpcMethodFnType = RPCHelpMan (*)();
 
 class CRPCCommand {
 public:
     //! RPC method handler reading request and assigning result. Should return
     //! true if request is fully handled, false if it should be passed on to
     //! subsequent handlers.
     using Actor =
         std::function<bool(const Config &config, const JSONRPCRequest &request,
                            UniValue &result, bool last_handler)>;
 
     //! Constructor taking Actor callback supporting multiple handlers.
     CRPCCommand(std::string _category, std::string _name, Actor _actor,
                 std::vector<std::string> _args, intptr_t _unique_id)
         : category(std::move(_category)), name(std::move(_name)),
           actor(std::move(_actor)), argNames(std::move(_args)),
           unique_id(_unique_id) {}
 
     //! Simplified constructor taking plain RpcMethodFnType function pointer.
     CRPCCommand(std::string _category, std::string name_in, RpcMethodFnType _fn,
                 std::vector<std::string> args_in)
         : CRPCCommand(
               _category, _fn().m_name,
               [_fn](const Config &config, const JSONRPCRequest &request,
                     UniValue &result, bool) {
                   result = _fn().HandleRequest(config, request);
                   return true;
               },
               _fn().GetArgNames(), intptr_t(_fn)) {
         CHECK_NONFATAL(_fn().m_name == name_in);
         CHECK_NONFATAL(_fn().GetArgNames() == args_in);
     }
 
     //! Simplified constructor taking plain const_rpcfn_type function pointer.
     CRPCCommand(const char *_category, const char *_name, rpcfn_type _fn,
                 std::initializer_list<const char *> _args)
         : CRPCCommand(
               _category, _name,
               [_fn](const Config &config, const JSONRPCRequest &request,
                     UniValue &result, bool) {
                   result = _fn(config, request);
                   return true;
               },
               {_args.begin(), _args.end()}, intptr_t(_fn)) {}
 
     std::string category;
     std::string name;
     Actor actor;
     std::vector<std::string> argNames;
     intptr_t unique_id;
 };
 
 /**
  * RPC command dispatcher.
  */
 class CRPCTable {
 private:
     std::map<std::string, std::vector<const CRPCCommand *>> mapCommands;
 
 public:
     CRPCTable();
     std::string help(const Config &config, const std::string &name,
                      const JSONRPCRequest &helpreq) const;
 
     /**
      * Execute a method.
      * @param request The JSONRPCRequest to execute
      * @returns Result of the call.
      * @throws an exception (UniValue) when an error happens.
      */
     UniValue execute(const Config &config, const JSONRPCRequest &request) const;
 
     /**
      * Returns a list of registered commands
      * @returns List of registered commands.
      */
     std::vector<std::string> listCommands() const;
 
     /**
      * Appends a CRPCCommand to the dispatch table.
      *
-     * Returns false if RPC server is already running (dump concurrency
-     * protection).
+     * Precondition: RPC server is not running
      *
      * Commands with different method names but the same unique_id will
      * be considered aliases, and only the first registered method name will
      * show up in the help text command listing. Aliased commands do not have
      * to have the same behavior. Server and client code can distinguish
      * between calls based on method name, and aliased commands can also
      * register different names, types, and numbers of parameters.
      */
-    bool appendCommand(const std::string &name, const CRPCCommand *pcmd);
+    void appendCommand(const std::string &name, const CRPCCommand *pcmd);
     bool removeCommand(const std::string &name, const CRPCCommand *pcmd);
 };
 
 bool IsDeprecatedRPCEnabled(const ArgsManager &args, const std::string &method);
 
 extern CRPCTable tableRPC;
 
 void StartRPC();
 void InterruptRPC();
 void StopRPC();
 std::string JSONRPCExecBatch(const Config &config, RPCServer &rpcServer,
                              const JSONRPCRequest &req, const UniValue &vReq);
 
 /**
  * Retrieves any serialization flags requested in command line argument
  */
 int RPCSerializationFlags();
 
 #endif // BITCOIN_RPC_SERVER_H