12 files changed, 271 insertions, 91 deletions
diff --git a/src/bench/bench_bitcoin.cpp b/src/bench/bench_bitcoin.cpp
index 1a2671e8d1..a820d67fa8 100644
--- a/src/bench/bench_bitcoin.cpp
+++ b/src/bench/bench_bitcoin.cpp
@@ -33,13 +33,21 @@ static void SetupBenchArgs()
     gArgs.AddArg("-plot-plotlyurl=<uri>", strprintf("URL to use for plotly.js (default: %s)", DEFAULT_PLOT_PLOTLYURL), false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-plot-width=<x>", strprintf("Plot width in pixel (default: %u)", DEFAULT_PLOT_WIDTH), false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-plot-height=<x>", strprintf("Plot height in pixel (default: %u)", DEFAULT_PLOT_HEIGHT), false, OptionsCategory::OPTIONS);
+
+    // Hidden
+    gArgs.AddArg("-h", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-help", "", false, OptionsCategory::HIDDEN);
 }
 
 int
 main(int argc, char** argv)
 {
     SetupBenchArgs();
-    gArgs.ParseParameters(argc, argv);
+    std::string error;
+    if (!gArgs.ParseParameters(argc, argv, error)) {
+        fprintf(stderr, "Error parsing command line arguments: %s\n", error.c_str());
+        return false;
+    }
 
     if (HelpRequested(gArgs)) {
         std::cout << gArgs.GetHelpMessage();
diff --git a/src/bitcoin-cli.cpp b/src/bitcoin-cli.cpp
index 84c0325014..be5ce14480 100644
--- a/src/bitcoin-cli.cpp
+++ b/src/bitcoin-cli.cpp
@@ -42,6 +42,7 @@ static void SetupCliArgs()
     gArgs.AddArg("-named", strprintf("Pass named instead of positional arguments (default: %s)", DEFAULT_NAMED), false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-rpcclienttimeout=<n>", strprintf("Timeout in seconds during HTTP requests, or 0 for no timeout. (default: %d)", DEFAULT_HTTP_CLIENT_TIMEOUT), false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-rpcconnect=<ip>", strprintf("Send commands to node running on <ip> (default: %s)", DEFAULT_RPCCONNECT), false, OptionsCategory::OPTIONS);
+    gArgs.AddArg("-rpccookiefile=<loc>", _("Location of the auth cookie. Relative paths will be prefixed by a net-specific datadir location. (default: data dir)"), false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-rpcpassword=<pw>", "Password for JSON-RPC connections", false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-rpcport=<port>", strprintf("Connect to JSON-RPC on <port> (default: %u or testnet: %u)", defaultBaseParams->RPCPort(), testnetBaseParams->RPCPort()), false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-rpcuser=<user>", "Username for JSON-RPC connections", false, OptionsCategory::OPTIONS);
@@ -49,6 +50,10 @@ static void SetupCliArgs()
     gArgs.AddArg("-rpcwallet=<walletname>", "Send RPC for non-default wallet on RPC server (needs to exactly match corresponding -wallet option passed to bitcoind)", false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-stdin", "Read extra arguments from standard input, one per line until EOF/Ctrl-D (recommended for sensitive information such as passphrases).  When combined with -stdinrpcpass, the first line from standard input is used for the RPC password.", false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-stdinrpcpass", strprintf("Read RPC password from standard input as a single line.  When combined with -stdin, the first line from standard input is used for the RPC password."), false, OptionsCategory::OPTIONS);
+
+    // Hidden
+    gArgs.AddArg("-h", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-help", "", false, OptionsCategory::HIDDEN);
 }
 
 //////////////////////////////////////////////////////////////////////////////
@@ -80,7 +85,11 @@ static int AppInitRPC(int argc, char* argv[])
     // Parameters
     //
     SetupCliArgs();
-    gArgs.ParseParameters(argc, argv);
+    std::string error;
+    if (!gArgs.ParseParameters(argc, argv, error)) {
+        fprintf(stderr, "Error parsing command line arguments: %s\n", error.c_str());
+        return EXIT_FAILURE;
+    }
     if (argc < 2 || HelpRequested(gArgs) || gArgs.IsArgSet("-version")) {
         std::string strUsage = strprintf("%s RPC client version", PACKAGE_NAME) + " " + FormatFullVersion() + "\n";
         if (!gArgs.IsArgSet("-version")) {
@@ -104,10 +113,8 @@ static int AppInitRPC(int argc, char* argv[])
         fprintf(stderr, "Error: Specified data directory \"%s\" does not exist.\n", gArgs.GetArg("-datadir", "").c_str());
         return EXIT_FAILURE;
     }
-    try {
-        gArgs.ReadConfigFiles();
-    } catch (const std::exception& e) {
-        fprintf(stderr,"Error reading configuration file: %s\n", e.what());
+    if (!gArgs.ReadConfigFiles(error, true)) {
+        fprintf(stderr, "Error reading configuration file: %s\n", error.c_str());
         return EXIT_FAILURE;
     }
     // Check for -testnet or -regtest parameter (BaseParams() calls are only valid after this clause)
diff --git a/src/bitcoin-tx.cpp b/src/bitcoin-tx.cpp
index 8b542dc9b8..3fb505d739 100644
--- a/src/bitcoin-tx.cpp
+++ b/src/bitcoin-tx.cpp
@@ -64,6 +64,10 @@ static void SetupBitcoinTxArgs()
 
     gArgs.AddArg("load=NAME:FILENAME", "Load JSON file FILENAME into register NAME", false, OptionsCategory::REGISTER_COMMANDS);
     gArgs.AddArg("set=NAME:JSON-STRING", "Set register NAME to given JSON-STRING", false, OptionsCategory::REGISTER_COMMANDS);
+
+    // Hidden
+    gArgs.AddArg("-h", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-help", "", false, OptionsCategory::HIDDEN);
 }
 
 //
@@ -76,7 +80,11 @@ static int AppInitRawTx(int argc, char* argv[])
     // Parameters
     //
     SetupBitcoinTxArgs();
-    gArgs.ParseParameters(argc, argv);
+    std::string error;
+    if (!gArgs.ParseParameters(argc, argv, error)) {
+        fprintf(stderr, "Error parsing command line arguments: %s\n", error.c_str());
+        return EXIT_FAILURE;
+    }
 
     // Check for -testnet or -regtest parameter (Params() calls are only valid after this clause)
     try {
diff --git a/src/bitcoind.cpp b/src/bitcoind.cpp
index 35c05dad41..a9b952e5a4 100644
--- a/src/bitcoind.cpp
+++ b/src/bitcoind.cpp
@@ -65,7 +65,11 @@ static bool AppInit(int argc, char* argv[])
 #if HAVE_DECL_DAEMON
     gArgs.AddArg("-daemon", "Run in the background as a daemon and accept commands", false, OptionsCategory::OPTIONS);
 #endif
-    gArgs.ParseParameters(argc, argv);
+    std::string error;
+    if (!gArgs.ParseParameters(argc, argv, error)) {
+        fprintf(stderr, "Error parsing command line arguments: %s\n", error.c_str());
+        return false;
+    }
 
     // Process help and version before taking care about datadir
     if (HelpRequested(gArgs) || gArgs.IsArgSet("-version")) {
@@ -94,11 +98,8 @@ static bool AppInit(int argc, char* argv[])
             fprintf(stderr, "Error: Specified data directory \"%s\" does not exist.\n", gArgs.GetArg("-datadir", "").c_str());
             return false;
         }
-        try
-        {
-            gArgs.ReadConfigFiles();
-        } catch (const std::exception& e) {
-            fprintf(stderr,"Error reading configuration file: %s\n", e.what());
+        if (!gArgs.ReadConfigFiles(error)) {
+            fprintf(stderr, "Error reading configuration file: %s\n", error.c_str());
             return false;
         }
         // Check for -testnet or -regtest parameter (Params() calls are only valid after this clause)
diff --git a/src/init.cpp b/src/init.cpp
index 882371946c..b4e2eec0d2 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -499,6 +499,23 @@ void SetupServerArgs()
     gArgs.AddArg("-rpcuser=<user>", "Username for JSON-RPC connections", false, OptionsCategory::RPC);
     gArgs.AddArg("-rpcworkqueue=<n>", strprintf("Set the depth of the work queue to service RPC calls (default: %d)", DEFAULT_HTTP_WORKQUEUE), true, OptionsCategory::RPC);
     gArgs.AddArg("-server", "Accept command line and JSON-RPC commands", false, OptionsCategory::RPC);
+
+    // Hidden options
+    gArgs.AddArg("-rpcssl", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-benchmark", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-h", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-help", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-socks", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-tor", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-debugnet", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-whitelistalwaysrelay", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-prematurewitness", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-walletprematurewitness", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-promiscuousmempoolflags", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-blockminsize", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-dbcrashratio", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-forcecompactdb", "", false, OptionsCategory::HIDDEN);
+    gArgs.AddArg("-usehd", "", false, OptionsCategory::HIDDEN);
 }
 
 std::string LicenseInfo()
diff --git a/src/interfaces/node.cpp b/src/interfaces/node.cpp
index 9270351176..4189ff7497 100644
--- a/src/interfaces/node.cpp
+++ b/src/interfaces/node.cpp
@@ -48,11 +48,11 @@ namespace {
 
 class NodeImpl : public Node
 {
-    void parseParameters(int argc, const char* const argv[]) override
+    bool parseParameters(int argc, const char* const argv[], std::string& error) override
     {
-        gArgs.ParseParameters(argc, argv);
+        return gArgs.ParseParameters(argc, argv, error);
     }
-    void readConfigFiles() override { gArgs.ReadConfigFiles(); }
+    bool readConfigFiles(std::string& error) override { return gArgs.ReadConfigFiles(error); }
     bool softSetArg(const std::string& arg, const std::string& value) override { return gArgs.SoftSetArg(arg, value); }
     bool softSetBoolArg(const std::string& arg, bool value) override { return gArgs.SoftSetBoolArg(arg, value); }
     void selectParams(const std::string& network) override { SelectParams(network); }
diff --git a/src/interfaces/node.h b/src/interfaces/node.h
index 2a1a8152df..8185c015a9 100644
--- a/src/interfaces/node.h
+++ b/src/interfaces/node.h
@@ -38,7 +38,7 @@ public:
     virtual ~Node() {}
 
     //! Set command line arguments.
-    virtual void parseParameters(int argc, const char* const argv[]) = 0;
+    virtual bool parseParameters(int argc, const char* const argv[], std::string& error) = 0;
 
     //! Set a command line argument if it doesn't already have a value
     virtual bool softSetArg(const std::string& arg, const std::string& value) = 0;
@@ -47,7 +47,7 @@ public:
     virtual bool softSetBoolArg(const std::string& arg, bool value) = 0;
 
     //! Load settings from configuration file.
-    virtual void readConfigFiles() = 0;
+    virtual bool readConfigFiles(std::string& error) = 0;
 
     //! Choose network parameters.
     virtual void selectParams(const std::string& network) = 0;
diff --git a/src/qt/bitcoin.cpp b/src/qt/bitcoin.cpp
index 87dfdb73d3..31d9f936e7 100644
--- a/src/qt/bitcoin.cpp
+++ b/src/qt/bitcoin.cpp
@@ -229,6 +229,9 @@ public:
     /// Get window identifier of QMainWindow (BitcoinGUI)
     WId getMainWinId() const;
 
+    /// Setup platform style
+    void setupPlatformStyle();
+
 public Q_SLOTS:
     void initializeResult(bool success);
     void shutdownResult();
@@ -315,10 +318,14 @@ BitcoinApplication::BitcoinApplication(interfaces::Node& node, int &argc, char *
     paymentServer(0),
     m_wallet_models(),
 #endif
-    returnValue(0)
+    returnValue(0),
+    platformStyle(0)
 {
     setQuitOnLastWindowClosed(false);
+}
 
+void BitcoinApplication::setupPlatformStyle()
+{
     // UI per-platform customization
     // This must be done inside the BitcoinApplication constructor, or after it, because
     // PlatformStyle::instantiate requires a QApplication
@@ -562,15 +569,9 @@ int main(int argc, char *argv[])
 
     std::unique_ptr<interfaces::Node> node = interfaces::MakeNode();
 
-    /// 1. Parse command-line options. These take precedence over anything else.
-    // Command-line options take precedence:
-    node->setupServerArgs();
-    SetupUIArgs();
-    node->parseParameters(argc, argv);
-
     // Do not refer to data directory yet, this can be overridden by Intro::pickDataDirectory
 
-    /// 2. Basic Qt initialization (not dependent on parameters or configuration)
+    /// 1. Basic Qt initialization (not dependent on parameters or configuration)
 #if QT_VERSION < 0x050000
     // Internal string conversion is all UTF-8
     QTextCodec::setCodecForTr(QTextCodec::codecForName("UTF-8"));
@@ -609,6 +610,20 @@ int main(int argc, char *argv[])
     qRegisterMetaType<WalletModel*>("WalletModel*");
 #endif
 
+    /// 2. Parse command-line options. We do this after qt in order to show an error if there are problems parsing these
+    // Command-line options take precedence:
+    node->setupServerArgs();
+    SetupUIArgs();
+    std::string error;
+    if (!node->parseParameters(argc, argv, error)) {
+        QMessageBox::critical(0, QObject::tr(PACKAGE_NAME),
+            QObject::tr("Error parsing command line arguments: %1.").arg(QString::fromStdString(error)));
+        return EXIT_FAILURE;
+    }
+
+    // Now that the QApplication is setup and we have parsed our parameters, we can set the platform style
+    app.setupPlatformStyle();
+
     /// 3. Application identification
     // must be set before OptionsModel is initialized or translations are loaded,
     // as it is used to locate QSettings
@@ -644,11 +659,9 @@ int main(int argc, char *argv[])
                               QObject::tr("Error: Specified data directory \"%1\" does not exist.").arg(QString::fromStdString(gArgs.GetArg("-datadir", ""))));
         return EXIT_FAILURE;
     }
-    try {
-        node->readConfigFiles();
-    } catch (const std::exception& e) {
+    if (!node->readConfigFiles(error)) {
         QMessageBox::critical(0, QObject::tr(PACKAGE_NAME),
-                              QObject::tr("Error: Cannot parse configuration file: %1. Only use key=value syntax.").arg(e.what()));
+            QObject::tr("Error: Cannot parse configuration file: %1.").arg(QString::fromStdString(error)));
         return EXIT_FAILURE;
     }
 
diff --git a/src/test/getarg_tests.cpp b/src/test/getarg_tests.cpp
index cd603b7f58..c065e25676 100644
--- a/src/test/getarg_tests.cpp
+++ b/src/test/getarg_tests.cpp
@@ -27,11 +27,21 @@ static void ResetArgs(const std::string& strArg)
     for (std::string& s : vecArg)
         vecChar.push_back(s.c_str());
 
-    gArgs.ParseParameters(vecChar.size(), vecChar.data());
+    std::string error;
+    gArgs.ParseParameters(vecChar.size(), vecChar.data(), error);
+}
+
+static void SetupArgs(const std::vector<std::string>& args)
+{
+    gArgs.ClearArgs();
+    for (const std::string& arg : args) {
+        gArgs.AddArg(arg, "", false, OptionsCategory::OPTIONS);
+    }
 }
 
 BOOST_AUTO_TEST_CASE(boolarg)
 {
+    SetupArgs({"-foo"});
     ResetArgs("-foo");
     BOOST_CHECK(gArgs.GetBoolArg("-foo", false));
     BOOST_CHECK(gArgs.GetBoolArg("-foo", true));
@@ -84,6 +94,7 @@ BOOST_AUTO_TEST_CASE(boolarg)
 
 BOOST_AUTO_TEST_CASE(stringarg)
 {
+    SetupArgs({"-foo", "-bar"});
     ResetArgs("");
     BOOST_CHECK_EQUAL(gArgs.GetArg("-foo", ""), "");
     BOOST_CHECK_EQUAL(gArgs.GetArg("-foo", "eleven"), "eleven");
@@ -108,6 +119,7 @@ BOOST_AUTO_TEST_CASE(stringarg)
 
 BOOST_AUTO_TEST_CASE(intarg)
 {
+    SetupArgs({"-foo", "-bar"});
     ResetArgs("");
     BOOST_CHECK_EQUAL(gArgs.GetArg("-foo", 11), 11);
     BOOST_CHECK_EQUAL(gArgs.GetArg("-foo", 0), 0);
@@ -127,6 +139,7 @@ BOOST_AUTO_TEST_CASE(intarg)
 
 BOOST_AUTO_TEST_CASE(doubledash)
 {
+    SetupArgs({"-foo", "-bar"});
     ResetArgs("--foo");
     BOOST_CHECK_EQUAL(gArgs.GetBoolArg("-foo", false), true);
 
@@ -137,6 +150,7 @@ BOOST_AUTO_TEST_CASE(doubledash)
 
 BOOST_AUTO_TEST_CASE(boolargno)
 {
+    SetupArgs({"-foo", "-bar"});
     ResetArgs("-nofoo");
     BOOST_CHECK(!gArgs.GetBoolArg("-foo", true));
     BOOST_CHECK(!gArgs.GetBoolArg("-foo", false));
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index 2af6d9e0f3..611ccc9b77 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -186,27 +186,37 @@ struct TestArgsManager : public ArgsManager
             LOCK(cs_args);
             m_config_args.clear();
         }
-        ReadConfigStream(streamConfig);
+        std::string error;
+        ReadConfigStream(streamConfig, error);
     }
     void SetNetworkOnlyArg(const std::string arg)
     {
         LOCK(cs_args);
         m_network_only_args.insert(arg);
     }
+    void SetupArgs(int argv, const char* args[])
+    {
+        for (int i = 0; i < argv; ++i) {
+            AddArg(args[i], "", false, OptionsCategory::OPTIONS);
+        }
+    }
 };
 
 BOOST_AUTO_TEST_CASE(util_ParseParameters)
 {
     TestArgsManager testArgs;
+    const char* avail_args[] = {"-a", "-b", "-ccc", "-d"};
     const char *argv_test[] = {"-ignored", "-a", "-b", "-ccc=argument", "-ccc=multiple", "f", "-d=e"};
 
-    testArgs.ParseParameters(0, (char**)argv_test);
+    std::string error;
+    testArgs.SetupArgs(4, avail_args);
+    testArgs.ParseParameters(0, (char**)argv_test, error);
     BOOST_CHECK(testArgs.GetOverrideArgs().empty() && testArgs.GetConfigArgs().empty());
 
-    testArgs.ParseParameters(1, (char**)argv_test);
+    testArgs.ParseParameters(1, (char**)argv_test, error);
     BOOST_CHECK(testArgs.GetOverrideArgs().empty() && testArgs.GetConfigArgs().empty());
 
-    testArgs.ParseParameters(7, (char**)argv_test);
+    testArgs.ParseParameters(7, (char**)argv_test, error);
     // expectation: -ignored is ignored (program name argument),
     // -a, -b and -ccc end up in map, -d ignored because it is after
     // a non-option argument (non-GNU option parsing)
@@ -227,9 +237,12 @@ BOOST_AUTO_TEST_CASE(util_ParseParameters)
 BOOST_AUTO_TEST_CASE(util_GetBoolArg)
 {
     TestArgsManager testArgs;
+    const char* avail_args[] = {"-a", "-b", "-c", "-d", "-e", "-f"};
     const char *argv_test[] = {
         "ignored", "-a", "-nob", "-c=0", "-d=1", "-e=false", "-f=true"};
-    testArgs.ParseParameters(7, (char**)argv_test);
+    std::string error;
+    testArgs.SetupArgs(6, avail_args);
+    testArgs.ParseParameters(7, (char**)argv_test, error);
 
     // Each letter should be set.
     for (char opt : "abcdef")
@@ -261,8 +274,11 @@ BOOST_AUTO_TEST_CASE(util_GetBoolArgEdgeCases)
     TestArgsManager testArgs;
 
     // Params test
+    const char* avail_args[] = {"-foo", "-bar"};
     const char *argv_test[] = {"ignored", "-nofoo", "-foo", "-nobar=0"};
-    testArgs.ParseParameters(4, (char**)argv_test);
+    testArgs.SetupArgs(2, avail_args);
+    std::string error;
+    testArgs.ParseParameters(4, (char**)argv_test, error);
 
     // This was passed twice, second one overrides the negative setting.
     BOOST_CHECK(!testArgs.IsArgNegated("-foo"));
@@ -274,7 +290,7 @@ BOOST_AUTO_TEST_CASE(util_GetBoolArgEdgeCases)
 
     // Config test
     const char *conf_test = "nofoo=1\nfoo=1\nnobar=0\n";
-    testArgs.ParseParameters(1, (char**)argv_test);
+    testArgs.ParseParameters(1, (char**)argv_test, error);
     testArgs.ReadConfigString(conf_test);
 
     // This was passed twice, second one overrides the negative setting,
@@ -289,7 +305,7 @@ BOOST_AUTO_TEST_CASE(util_GetBoolArgEdgeCases)
     // Combined test
     const char *combo_test_args[] = {"ignored", "-nofoo", "-bar"};
     const char *combo_test_conf = "foo=1\nnobar=1\n";
-    testArgs.ParseParameters(3, (char**)combo_test_args);
+    testArgs.ParseParameters(3, (char**)combo_test_args, error);
     testArgs.ReadConfigString(combo_test_conf);
 
     // Command line overrides, but doesn't erase old setting
@@ -329,6 +345,8 @@ BOOST_AUTO_TEST_CASE(util_ReadConfigStream)
        "iii=2\n";
 
     TestArgsManager test_args;
+    const char* avail_args[] = {"-a", "-b", "-ccc", "-d", "-e", "-fff", "-ggg", "-h", "-i", "-iii"};
+    test_args.SetupArgs(10, avail_args);
 
     test_args.ReadConfigString(str_config);
     // expectation: a, b, ccc, d, fff, ggg, h, i end up in map
@@ -526,6 +544,8 @@ BOOST_AUTO_TEST_CASE(util_GetArg)
 BOOST_AUTO_TEST_CASE(util_GetChainName)
 {
     TestArgsManager test_args;
+    const char* avail_args[] = {"-testnet", "-regtest"};
+    test_args.SetupArgs(2, avail_args);
 
     const char* argv_testnet[] = {"cmd", "-testnet"};
     const char* argv_regtest[] = {"cmd", "-regtest"};
@@ -535,39 +555,40 @@ BOOST_AUTO_TEST_CASE(util_GetChainName)
     // equivalent to "-testnet"
     // regtest in testnet section is ignored
     const char* testnetconf = "testnet=1\nregtest=0\n[test]\nregtest=1";
+    std::string error;
 
-    test_args.ParseParameters(0, (char**)argv_testnet);
+    test_args.ParseParameters(0, (char**)argv_testnet, error);
     BOOST_CHECK_EQUAL(test_args.GetChainName(), "main");
 
-    test_args.ParseParameters(2, (char**)argv_testnet);
+    test_args.ParseParameters(2, (char**)argv_testnet, error);
     BOOST_CHECK_EQUAL(test_args.GetChainName(), "test");
 
-    test_args.ParseParameters(2, (char**)argv_regtest);
+    test_args.ParseParameters(2, (char**)argv_regtest, error);
     BOOST_CHECK_EQUAL(test_args.GetChainName(), "regtest");
 
-    test_args.ParseParameters(3, (char**)argv_test_no_reg);
+    test_args.ParseParameters(3, (char**)argv_test_no_reg, error);
     BOOST_CHECK_EQUAL(test_args.GetChainName(), "test");
 
-    test_args.ParseParameters(3, (char**)argv_both);
+    test_args.ParseParameters(3, (char**)argv_both, error);
     BOOST_CHECK_THROW(test_args.GetChainName(), std::runtime_error);
 
-    test_args.ParseParameters(0, (char**)argv_testnet);
+    test_args.ParseParameters(0, (char**)argv_testnet, error);
     test_args.ReadConfigString(testnetconf);
     BOOST_CHECK_EQUAL(test_args.GetChainName(), "test");
 
-    test_args.ParseParameters(2, (char**)argv_testnet);
+    test_args.ParseParameters(2, (char**)argv_testnet, error);
     test_args.ReadConfigString(testnetconf);
     BOOST_CHECK_EQUAL(test_args.GetChainName(), "test");
 
-    test_args.ParseParameters(2, (char**)argv_regtest);
+    test_args.ParseParameters(2, (char**)argv_regtest, error);
     test_args.ReadConfigString(testnetconf);
     BOOST_CHECK_THROW(test_args.GetChainName(), std::runtime_error);
 
-    test_args.ParseParameters(3, (char**)argv_test_no_reg);
+    test_args.ParseParameters(3, (char**)argv_test_no_reg, error);
     test_args.ReadConfigString(testnetconf);
     BOOST_CHECK_EQUAL(test_args.GetChainName(), "test");
 
-    test_args.ParseParameters(3, (char**)argv_both);
+    test_args.ParseParameters(3, (char**)argv_both, error);
     test_args.ReadConfigString(testnetconf);
     BOOST_CHECK_THROW(test_args.GetChainName(), std::runtime_error);
 
@@ -575,23 +596,23 @@ BOOST_AUTO_TEST_CASE(util_GetChainName)
     // [test] regtest=1 potentially relevant) doesn't break things
     test_args.SelectConfigNetwork("test");
 
-    test_args.ParseParameters(0, (char**)argv_testnet);
+    test_args.ParseParameters(0, (char**)argv_testnet, error);
     test_args.ReadConfigString(testnetconf);
     BOOST_CHECK_EQUAL(test_args.GetChainName(), "test");
 
-    test_args.ParseParameters(2, (char**)argv_testnet);
+    test_args.ParseParameters(2, (char**)argv_testnet, error);
     test_args.ReadConfigString(testnetconf);
     BOOST_CHECK_EQUAL(test_args.GetChainName(), "test");
 
-    test_args.ParseParameters(2, (char**)argv_regtest);
+    test_args.ParseParameters(2, (char**)argv_regtest, error);
     test_args.ReadConfigString(testnetconf);
     BOOST_CHECK_THROW(test_args.GetChainName(), std::runtime_error);
 
-    test_args.ParseParameters(2, (char**)argv_test_no_reg);
+    test_args.ParseParameters(2, (char**)argv_test_no_reg, error);
     test_args.ReadConfigString(testnetconf);
     BOOST_CHECK_EQUAL(test_args.GetChainName(), "test");
 
-    test_args.ParseParameters(3, (char**)argv_both);
+    test_args.ParseParameters(3, (char**)argv_both, error);
     test_args.ReadConfigString(testnetconf);
     BOOST_CHECK_THROW(test_args.GetChainName(), std::runtime_error);
 }
diff --git a/src/util.cpp b/src/util.cpp
index 963a7f531f..34483d95b0 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -412,7 +412,7 @@ void ArgsManager::SelectConfigNetwork(const std::string& network)
     m_network = network;
 }
 
-void ArgsManager::ParseParameters(int argc, const char* const argv[])
+bool ArgsManager::ParseParameters(int argc, const char* const argv[], std::string& error)
 {
     LOCK(cs_args);
     m_override_args.clear();
@@ -444,6 +444,14 @@ void ArgsManager::ParseParameters(int argc, const char* const argv[])
         } else {
             m_override_args[key].push_back(val);
         }
+
+        // Check that the arg is known
+        if (!(IsSwitchChar(key[0]) && key.size() == 1)) {
+            if (!IsArgKnown(key, error)) {
+                error = strprintf("Invalid parameter %s", key.c_str());
+                return false;
+            }
+        }
     }
 
     // we do not allow -includeconf from command line, so we clear it here
@@ -456,6 +464,23 @@ void ArgsManager::ParseParameters(int argc, const char* const argv[])
             m_override_args.erase(it);
         }
     }
+    return true;
+}
+
+bool ArgsManager::IsArgKnown(const std::string& key, std::string& error)
+{
+    size_t option_index = key.find('.');
+    std::string arg_no_net;
+    if (option_index == std::string::npos) {
+        arg_no_net = key;
+    } else {
+        arg_no_net = std::string("-") + key.substr(option_index + 1, std::string::npos);
+    }
+
+    for (const auto& arg_map : m_available_args) {
+        if (arg_map.second.count(arg_no_net)) return true;
+    }
+    return false;
 }
 
 std::vector<std::string> ArgsManager::GetArgs(const std::string& strArg) const
@@ -549,48 +574,80 @@ void ArgsManager::ForceSetArg(const std::string& strArg, const std::string& strV
 
 void ArgsManager::AddArg(const std::string& name, const std::string& help, const bool debug_only, const OptionsCategory& cat)
 {
-    std::pair<OptionsCategory, std::string> key(cat, name);
-    assert(m_available_args.count(key) == 0);
-    m_available_args.emplace(key, std::pair<std::string, bool>(help, debug_only));
+    // Split arg name from its help param
+    size_t eq_index = name.find('=');
+    if (eq_index == std::string::npos) {
+        eq_index = name.size();
+    }
+
+    std::map<std::string, Arg>& arg_map = m_available_args[cat];
+    auto ret = arg_map.emplace(name.substr(0, eq_index), Arg(name.substr(eq_index, name.size() - eq_index), help, debug_only));
+    assert(ret.second); // Make sure an insertion actually happened
 }
 
 std::string ArgsManager::GetHelpMessage()
 {
     const bool show_debug = gArgs.GetBoolArg("-help-debug", false);
 
-    std::string usage = HelpMessageGroup("Options:");
-
-    OptionsCategory last_cat = OptionsCategory::OPTIONS;
-    for (auto& arg : m_available_args) {
-        if (arg.first.first != last_cat) {
-            last_cat = arg.first.first;
-            if (last_cat == OptionsCategory::CONNECTION)
+    std::string usage = "";
+    for (const auto& arg_map : m_available_args) {
+        switch(arg_map.first) {
+            case OptionsCategory::OPTIONS:
+                usage += HelpMessageGroup("Options:");
+                break;
+            case OptionsCategory::CONNECTION:
                 usage += HelpMessageGroup("Connection options:");
-            else if (last_cat == OptionsCategory::ZMQ)
+                break;
+            case OptionsCategory::ZMQ:
                 usage += HelpMessageGroup("ZeroMQ notification options:");
-            else if (last_cat == OptionsCategory::DEBUG_TEST)
+                break;
+            case OptionsCategory::DEBUG_TEST:
                 usage += HelpMessageGroup("Debugging/Testing options:");
-            else if (last_cat == OptionsCategory::NODE_RELAY)
+                break;
+            case OptionsCategory::NODE_RELAY:
                 usage += HelpMessageGroup("Node relay options:");
-            else if (last_cat == OptionsCategory::BLOCK_CREATION)
+                break;
+            case OptionsCategory::BLOCK_CREATION:
                 usage += HelpMessageGroup("Block creation options:");
-            else if (last_cat == OptionsCategory::RPC)
+                break;
+            case OptionsCategory::RPC:
                 usage += HelpMessageGroup("RPC server options:");
-            else if (last_cat == OptionsCategory::WALLET)
+                break;
+            case OptionsCategory::WALLET:
                 usage += HelpMessageGroup("Wallet options:");
-            else if (last_cat == OptionsCategory::WALLET_DEBUG_TEST && show_debug)
-                usage += HelpMessageGroup("Wallet debugging/testing options:");
-            else if (last_cat == OptionsCategory::CHAINPARAMS)
+                break;
+            case OptionsCategory::WALLET_DEBUG_TEST:
+                if (show_debug) usage += HelpMessageGroup("Wallet debugging/testing options:");
+                break;
+            case OptionsCategory::CHAINPARAMS:
                 usage += HelpMessageGroup("Chain selection options:");
-            else if (last_cat == OptionsCategory::GUI)
+                break;
+            case OptionsCategory::GUI:
                 usage += HelpMessageGroup("UI Options:");
-            else if (last_cat == OptionsCategory::COMMANDS)
+                break;
+            case OptionsCategory::COMMANDS:
                 usage += HelpMessageGroup("Commands:");
-            else if (last_cat == OptionsCategory::REGISTER_COMMANDS)
+                break;
+            case OptionsCategory::REGISTER_COMMANDS:
                 usage += HelpMessageGroup("Register Commands:");
+                break;
+            default:
+                break;
         }
-        if (show_debug || !arg.second.second) {
-            usage += HelpMessageOpt(arg.first.second, arg.second.first);
+
+        // When we get to the hidden options, stop
+        if (arg_map.first == OptionsCategory::HIDDEN) break;
+
+        for (const auto& arg : arg_map.second) {
+            if (show_debug || !arg.second.m_debug_only) {
+                std::string name;
+                if (arg.second.m_help_param.empty()) {
+                    name = arg.first;
+                } else {
+                    name = arg.first + arg.second.m_help_param;
+                }
+                usage += HelpMessageOpt(name, arg.second.m_help_text);
+            }
         }
     }
     return usage;
@@ -747,7 +804,7 @@ fs::path GetConfigFile(const std::string& confPath)
     return AbsPathForConfigVal(fs::path(confPath), false);
 }
 
-void ArgsManager::ReadConfigStream(std::istream& stream)
+bool ArgsManager::ReadConfigStream(std::istream& stream, std::string& error, bool ignore_invalid_keys)
 {
     LOCK(cs_args);
 
@@ -758,15 +815,23 @@ void ArgsManager::ReadConfigStream(std::istream& stream)
     {
         std::string strKey = std::string("-") + it->string_key;
         std::string strValue = it->value[0];
+
         if (InterpretNegatedOption(strKey, strValue)) {
             m_config_args[strKey].clear();
         } else {
             m_config_args[strKey].push_back(strValue);
         }
+
+        // Check that the arg is known
+        if (!IsArgKnown(strKey, error) && !ignore_invalid_keys) {
+            error = strprintf("Invalid configuration value %s", it->string_key.c_str());
+            return false;
+        }
     }
+    return true;
 }
 
-void ArgsManager::ReadConfigFiles()
+bool ArgsManager::ReadConfigFiles(std::string& error, bool ignore_invalid_keys)
 {
     {
         LOCK(cs_args);
@@ -778,7 +843,9 @@ void ArgsManager::ReadConfigFiles()
 
     // ok to not have a config file
     if (stream.good()) {
-        ReadConfigStream(stream);
+        if (!ReadConfigStream(stream, error, ignore_invalid_keys)) {
+            return false;
+        }
         // if there is an -includeconf in the override args, but it is empty, that means the user
         // passed '-noincludeconf' on the command line, in which case we should not include anything
         if (m_override_args.count("-includeconf") == 0) {
@@ -801,7 +868,9 @@ void ArgsManager::ReadConfigFiles()
             for (const std::string& to_include : includeconf) {
                 fs::ifstream include_config(GetConfigFile(to_include));
                 if (include_config.good()) {
-                    ReadConfigStream(include_config);
+                    if (!ReadConfigStream(include_config, error, ignore_invalid_keys)) {
+                        return false;
+                    }
                     LogPrintf("Included configuration file %s\n", to_include.c_str());
                 } else {
                     fprintf(stderr, "Failed to include configuration file %s\n", to_include.c_str());
@@ -823,8 +892,10 @@ void ArgsManager::ReadConfigFiles()
     // If datadir is changed in .conf file:
     ClearDatadirCache();
     if (!fs::is_directory(GetDataDir(false))) {
-        throw std::runtime_error(strprintf("specified data directory \"%s\" does not exist.", gArgs.GetArg("-datadir", "").c_str()));
+        error = strprintf("specified data directory \"%s\" does not exist.", gArgs.GetArg("-datadir", "").c_str());
+        return false;
     }
+    return true;
 }
 
 std::string ArgsManager::GetChainName() const
diff --git a/src/util.h b/src/util.h
index 17dd5c0683..62c3f7c18b 100644
--- a/src/util.h
+++ b/src/util.h
@@ -118,8 +118,7 @@ inline bool IsSwitchChar(char c)
 #endif
 }
 
-enum class OptionsCategory
-{
+enum class OptionsCategory {
     OPTIONS,
     CONNECTION,
     WALLET,
@@ -132,7 +131,9 @@ enum class OptionsCategory
     RPC,
     GUI,
     COMMANDS,
-    REGISTER_COMMANDS
+    REGISTER_COMMANDS,
+
+    HIDDEN // Always the last option to avoid printing these in the help
 };
 
 class ArgsManager
@@ -140,14 +141,23 @@ class ArgsManager
 protected:
     friend class ArgsManagerHelper;
 
+    struct Arg
+    {
+        std::string m_help_param;
+        std::string m_help_text;
+        bool m_debug_only;
+
+        Arg(const std::string& help_param, const std::string& help_text, bool debug_only) : m_help_param(help_param), m_help_text(help_text), m_debug_only(debug_only) {};
+    };
+
     mutable CCriticalSection cs_args;
     std::map<std::string, std::vector<std::string>> m_override_args;
     std::map<std::string, std::vector<std::string>> m_config_args;
     std::string m_network;
     std::set<std::string> m_network_only_args;
-    std::map<std::pair<OptionsCategory, std::string>, std::pair<std::string, bool>> m_available_args;
+    std::map<OptionsCategory, std::map<std::string, Arg>> m_available_args;
 
-    void ReadConfigStream(std::istream& stream);
+    bool ReadConfigStream(std::istream& stream, std::string& error, bool ignore_invalid_keys = false);
 
 public:
     ArgsManager();
@@ -157,8 +167,8 @@ public:
      */
     void SelectConfigNetwork(const std::string& network);
 
-    void ParseParameters(int argc, const char*const argv[]);
-    void ReadConfigFiles();
+    bool ParseParameters(int argc, const char* const argv[], std::string& error);
+    bool ReadConfigFiles(std::string& error, bool ignore_invalid_keys = false);
 
     /**
      * Log warnings for options in m_section_only_args when
@@ -254,9 +264,19 @@ public:
     void AddArg(const std::string& name, const std::string& help, const bool debug_only, const OptionsCategory& cat);
 
     /**
+     * Clear available arguments
+     */
+    void ClearArgs() { m_available_args.clear(); }
+
+    /**
      * Get the help string
      */
     std::string GetHelpMessage();
+
+    /**
+     * Check whether we know of this arg
+     */
+    bool IsArgKnown(const std::string& key, std::string& error);
 };
 
 extern ArgsManager gArgs;