friendlier error message when using a renamed option

arangod/RestServer/CheckVersionFeature.cpp

@@ -54,6 +54,8 @@ CheckVersionFeature::CheckVersionFeature(
 void CheckVersionFeature::collectOptions(
     std::shared_ptr<ProgramOptions> options) {
   options->addSection("database", "Configure the database");
+  
+  options->addOldOption("check-version", "database.check-version");
 
   options->addHiddenOption("--database.check-version",
                            "checks the versions of the database and exit",

arangod/RestServer/DatabaseFeature.cpp

@@ -69,6 +69,8 @@ DatabaseFeature::DatabaseFeature(ApplicationServer* server)
 
 void DatabaseFeature::collectOptions(std::shared_ptr<ProgramOptions> options) {
   options->addSection("database", "Configure the database");
+  
+  options->addOldOption("server.disable-replication-applier", "database.replication-applier");
 
   options->addOption("--database.directory", "path to the database directory",
                      new StringParameter(&_directory));

arangod/RestServer/EndpointFeature.cpp

@@ -51,6 +51,9 @@ EndpointFeature::EndpointFeature(
 }
 
 void EndpointFeature::collectOptions(std::shared_ptr<ProgramOptions> options) {
+  options->addOldOption("server.backlog-size", "tcp.backlog-size");
+  options->addOldOption("server.reuse-address", "tcp.reuse-address");
+
   options->addSection("server", "Server features");
 
   options->addOption("--server.endpoint",

arangod/RestServer/QueryRegistryFeature.cpp

@@ -46,6 +46,10 @@ QueryRegistryFeature::QueryRegistryFeature(ApplicationServer* server)
 void QueryRegistryFeature::collectOptions(
     std::shared_ptr<ProgramOptions> options) {
   options->addSection("query", "Configure queries");
+  
+  options->addOldOption("database.query-cache-mode", "query.cache-mode");
+  options->addOldOption("database.query-cache-max-results", "query.cache-entries");
+  options->addOldOption("database.disable-query-tracking", "query.tracking");
 
   options->addOption("--query.tracking", "whether to track queries",
                      new BooleanParameter(&_queryTracking));

arangod/RestServer/RestServerFeature.cpp

@@ -108,6 +108,14 @@ void RestServerFeature::collectOptions(
     std::shared_ptr<ProgramOptions> options) {
   options->addSection("server", "Server features");
   
+  options->addOldOption("server.disable-authentication", "server.authentication");
+  options->addOldOption("server.disable-authentication-unix-sockets", "server.authentication-unix-sockets");
+  options->addOldOption("server.authenticate-system-only", "server.authentication-system-only");
+  options->addOldOption("server.allow-method-override", "http.allow-method-override");
+  options->addOldOption("server.hide-product-header", "http.hide-product-header");
+  options->addOldOption("server.keep-alive-timeout", "http.keep-alive-timeout");
+  options->addOldOption("server.default-api-compatibility", "");
+
   options->addOption("--server.authentication",
                      "enable or disable authentication for ALL client requests",
                      new BooleanParameter(&_authentication));

arangod/RestServer/UpgradeFeature.cpp

@@ -58,6 +58,8 @@ UpgradeFeature::UpgradeFeature(
 
 void UpgradeFeature::collectOptions(std::shared_ptr<ProgramOptions> options) {
   options->addSection("database", "Configure the database");
+  
+  options->addOldOption("upgrade", "--database.auto-upgrade");
 
   options->addOption("--database.auto-upgrade",
                      "perform a database upgrade if necessary",

arangod/Statistics/StatisticsFeature.cpp

@@ -39,6 +39,8 @@ StatisticsFeature::StatisticsFeature(application_features::ApplicationServer* se
 }
 
 void StatisticsFeature::collectOptions(std::shared_ptr<ProgramOptions> options) {
+  options->addOldOption("server.disable-statistics", "server.statistics");
+  
   options->addSection("server", "Server features");
 
   options->addHiddenOption(

arangod/V8Server/FoxxQueuesFeature.cpp

@@ -40,6 +40,9 @@ FoxxQueuesFeature::FoxxQueuesFeature(
 
 void FoxxQueuesFeature::collectOptions(std::shared_ptr<ProgramOptions> options) {
   options->addSection("foxx", "Configure Foxx");
+  
+  options->addOldOption("server.foxx-queues", "foxx.queues");
+  options->addOldOption("server.foxx-queues-poll-interval", "foxx.queues-poll-interval");
 
   options->addOption(
       "--foxx.queues", 

lib/ApplicationFeatures/TempFeature.cpp

@@ -41,6 +41,8 @@ TempFeature::TempFeature(application_features::ApplicationServer* server,
 }
 
 void TempFeature::collectOptions(std::shared_ptr<ProgramOptions> options) {
+  options->addOldOption("temp-path", "temp.path");
+
   options->addSection("temp", "Configure the temporary files");
 
   options->addOption("--temp.path", "path for temporary files",

lib/Logger/LoggerFeature.cpp

@@ -64,6 +64,12 @@ LoggerFeature::LoggerFeature(application_features::ApplicationServer* server,
 }
 
 void LoggerFeature::collectOptions(std::shared_ptr<ProgramOptions> options) {
+  options->addOldOption("log.tty", "log.foreground-tty");
+  options->addOldOption("log.content-filter", "");
+  options->addOldOption("log.source-filter", "");
+  options->addOldOption("log.application", "");
+  options->addOldOption("log.facility", "");
+  
   options->addHiddenOption("--log", "the global or topic-specific log level",
                            new VectorParameter<StringParameter>(&_levels));
 

lib/ProgramOptions/ProgramOptions.h

@@ -141,6 +141,16 @@ class ProgramOptions {
   // set context for error reporting
   void setContext(std::string const& value) { _context = value; }
 
+  // sets the old options map
+  void setOldOptions(std::unordered_map<std::string, std::string> const& old) {
+    _oldOptions = old;
+  }
+ 
+  // sets a single old option and its replacement name 
+  void addOldOption(std::string const& old, std::string const& replacement) {
+    _oldOptions[old] = replacement;
+  }
+
   // adds a section to the options
   void addSection(Section const& section) {
     checkIfSealed();
@@ -364,7 +374,7 @@ class ProgramOptions {
     return (*it2).second.parameter->requiresValue();
   }
 
-  // returns a pointer to an option, specified by option name
+  // returns a pointer to an option value, specified by option name
   // returns a nullptr if the option is unknown
   template <typename T>
   T* get(std::string const& name) {
@@ -385,20 +395,83 @@ class ProgramOptions {
 
     return dynamic_cast<T>(option.parameter.get());
   }
+  
+  // returns an option description
+  std::string getDescription(std::string const& name) {
+    auto parts = Option::splitName(name);
+    auto it = _sections.find(parts.first);
+
+    if (it == _sections.end()) {
+      return "";
+    }
+
+    auto it2 = (*it).second.options.find(parts.second);
+
+    if (it2 == (*it).second.options.end()) {
+      return "";
+    }
+
+    return (*it2).second.description;
+  }
 
   // handle an unknown option
   bool unknownOption(std::string const& name) {
-    fail("unknown option '--" + name + "'");
+    char const* colorStart;
+    char const* colorEnd;
+
+    if (isatty(STDERR_FILENO)) {
+      colorStart = TRI_SHELL_COLOR_BRIGHT;
+      colorEnd = TRI_SHELL_COLOR_RESET;
+    } else {
+      colorStart = colorEnd = "";
+    }
+
+    fail(std::string("unknown option '") + colorStart + "--" + name + colorEnd + "'");
 
     auto similarOptions = similar(name, 8, 4);
     if (!similarOptions.empty()) {
-      std::cerr << "Did you mean one of these?" << std::endl;
+      if (similarOptions.size() == 1) {
+        std::cerr << "Did you mean this?" << std::endl;
+      } else {
+        std::cerr << "Did you mean one of these?" << std::endl;
+      }
+      // determine maximum width
+      size_t maxWidth = 0;
       for (auto const& it : similarOptions) {
-        std::cerr << "  " << it << std::endl;
+        maxWidth = (std::max)(maxWidth, it.size());
+      }
+
+      for (auto const& it : similarOptions) {
+        std::cerr << "  " << colorStart << Option::pad(it, maxWidth) << colorEnd
+                  << "    " << getDescription(it) 
+                  << std::endl;
       }
       std::cerr << std::endl;
     }
-    std::cerr << "Use --help or --help-all to get an overview of available options" 
+    
+    auto it = _oldOptions.find(name);
+    if (it != _oldOptions.end()) {
+      // a now removed or renamed option was specified...
+      auto& now = (*it).second;
+      if (now.empty()) {
+        std::cerr << "Please note that the specified option '"
+                  << colorStart << "--" << name << colorEnd 
+                  << "' has been removed in this ArangoDB version"; 
+      } else {
+        std::cerr << "Please note that the specified option '" 
+                  << colorStart << "--" << name << colorEnd 
+                  << "' has been renamed to '--" << colorStart
+                  << now << colorEnd << "' in this ArangoDB version"; 
+      }
+
+      std::cerr << std::endl 
+                << "Please be sure to read the manual section about changed options" 
+                << std::endl << std::endl;
+    }
+
+    std::cerr << "Use " << colorStart << "--help" << colorEnd 
+              << " or " << colorStart << "--help-all" << colorEnd
+              << " to get an overview of available options"
               << std::endl << std::endl; 
     
     return false;
@@ -507,6 +580,9 @@ class ProgramOptions {
   // shorthands for options, translating from short options to long option names
   // e.g. "-c" to "--configuration"
   std::unordered_map<std::string, std::string> _shorthands;
+  // map with old options and their new equivalents, used for printing more
+  // meaningful error messages when an invalid (but once valid) option was used
+  std::unordered_map<std::string, std::string> _oldOptions;
   // callback function for determining the terminal width
   TerminalWidthFuncType _terminalWidth;
   // callback function for determining the similarity between two option names

lib/Ssl/SslServerFeature.cpp

@@ -52,6 +52,13 @@ SslServerFeature::SslServerFeature(application_features::ApplicationServer* serv
 }
 
 void SslServerFeature::collectOptions(std::shared_ptr<ProgramOptions> options) {
+  options->addOldOption("server.cafile", "ssl.cafile");
+  options->addOldOption("server.keyfile", "ssl.keyfile");
+  options->addOldOption("server.ssl-cache", "ssl.session-cache");
+  options->addOldOption("server.ssl-cipher-list", "ssl.cipher-list");
+  options->addOldOption("server.ssl-options", "ssl.options");
+  options->addOldOption("server.ssl-protocol", "ssl.protocol");
+
   options->addSection("ssl", "Configure SSL communication");
 
   options->addOption("--ssl.cafile", "ca file used for secure connections",