Give an error and exit if there are unknown parameters

If an unknown option is given via either the command line args or
the conf file, throw an error and exit

Update tests for ArgsManager knowing args

Ignore unknown options in the config file for bitcoin-cli

Fix tests and bitcoin-cli to match actual options used

12 files changed, 205 insertions, 66 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 7f9a1d5609..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
@@ -779,7 +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);
 
@@ -790,15 +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);
@@ -810,7 +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) {
@@ -833,7 +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());
@@ -855,8 +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 1d318e2851..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
@@ -156,7 +157,7 @@ protected:
     std::set<std::string> m_network_only_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();
@@ -166,8 +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
@@ -263,9 +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;