Added a check for incorrect settings

programs/server/Server.cpp

@@ -125,6 +125,7 @@ namespace ErrorCodes
     extern const int FAILED_TO_GETPWUID;
     extern const int MISMATCHING_USERS_FOR_PROCESS_AND_DATA;
     extern const int NETWORK_ERROR;
+    extern const int UNKNOWN_ELEMENT_IN_CONFIG;
 }
 
 
@@ -210,6 +211,32 @@ void Server::defineOptions(Poco::Util::OptionSet & options)
     BaseDaemon::defineOptions(options);
 }
 
+
+/// Check that there is no user-level settings at the top level in config.
+/// This is a common source of mistake (user don't know where to write user-level setting).
+void checkForIncorrectSettings(const Poco::Util::AbstractConfiguration & config, const std::string & path)
+{
+    if (config.getBool("skip_check_for_incorrect_settings", false))
+        return;
+
+    Settings settings;
+    for (const auto & setting : settings)
+    {
+        std::string name = setting.getName().toString();
+        if (config.has(name))
+        {
+            throw Exception(fmt::format("A setting '{}' appeared at top level in config {}."
+                " But it is user-level setting that should be located in users.xml inside <profiles> section for specific profile."
+                " You can add it to <profiles><default> if you want to change default value of this setting."
+                " You can also disable the check - specify <skip_check_for_incorrect_settings>1</skip_check_for_incorrect_settings>"
+                " in the main configuration file.",
+                name, path),
+                ErrorCodes::UNKNOWN_ELEMENT_IN_CONFIG);
+        }
+    }
+}
+
+
 int Server::main(const std::vector<std::string> & /*args*/)
 {
     Poco::Logger * log = &logger();
@@ -269,6 +296,8 @@ int Server::main(const std::vector<std::string> & /*args*/)
         config().add(loaded_config.configuration.duplicate(), PRIO_DEFAULT, false);
     }
 
+    checkForIncorrectSettings(config(), config_path);
+
     const auto memory_amount = getMemoryAmount();
 
 #if defined(OS_LINUX)
@@ -473,13 +502,16 @@ int Server::main(const std::vector<std::string> & /*args*/)
         SensitiveDataMasker::setInstance(std::make_unique<SensitiveDataMasker>(config(), "query_masking_rules"));
     }
 
-    auto main_config_reloader = std::make_unique<ConfigReloader>(config_path,
+    auto main_config_reloader = std::make_unique<ConfigReloader>(
+        config_path,
         include_from_path,
         config().getString("path", ""),
         std::move(main_config_zk_node_cache),
         main_config_zk_changed_event,
         [&](ConfigurationPtr config)
         {
+            checkForIncorrectSettings(*config, config_path);
+
             // FIXME logging-related things need synchronization -- see the 'Logger * log' saved
             // in a lot of places. For now, disable updating log configuration without server restart.
             //setTextLog(global_context->getTextLog());
@@ -508,12 +540,17 @@ int Server::main(const std::vector<std::string> & /*args*/)
         if (Poco::File(config_dir + users_config_path).exists())
             users_config_path = config_dir + users_config_path;
     }
-    auto users_config_reloader = std::make_unique<ConfigReloader>(users_config_path,
+    auto users_config_reloader = std::make_unique<ConfigReloader>(
+        users_config_path,
         include_from_path,
         config().getString("path", ""),
         zkutil::ZooKeeperNodeCache([&] { return global_context->getZooKeeper(); }),
         std::make_shared<Poco::Event>(),
-        [&](ConfigurationPtr config) { global_context->setUsersConfig(config); },
+        [&](ConfigurationPtr config)
+        {
+            global_context->setUsersConfig(config);
+            checkForIncorrectSettings(*config, users_config_path);
+        },
         /* already_loaded = */ false);
 
     /// Reload config in SYSTEM RELOAD CONFIG query.

programs/server/config.xml

@@ -1,6 +1,9 @@
 <?xml version="1.0"?>
 <!--
   NOTE: User and query level settings are set up in "users.xml" file.
+  If you have accidentially specified user-level settings here, server won't start.
+  You can either move the settings to the right place inside "users.xml" file
+   or add <skip_check_for_incorrect_settings>1</skip_check_for_incorrect_settings> here.
 -->
 <yandex>
     <logger>