try to fix some undefined behavior on cluster startup

arangod/Agency/AgencyFeature.cpp

@@ -50,6 +50,7 @@ AgencyFeature::AgencyFeature(application_features::ApplicationServer* server)
   startsAfter("Database");
   startsAfter("Dispatcher");
   startsAfter("Endpoint");
+  startsAfter("QueryRegistry");
   startsAfter("Scheduler");
   startsAfter("Server");
 }

arangod/Agency/Agent.cpp

@@ -25,6 +25,7 @@
 
 #include "Basics/ConditionLocker.h"
 #include "RestServer/DatabaseFeature.h"
+#include "RestServer/QueryRegistryFeature.h"
 #include "VocBase/server.h"
 #include "VocBase/vocbase.h"
 
@@ -279,13 +280,12 @@ append_entries_t Agent::sendAppendEntriesRPC (id_t follower_id) {
      0, true);
 
   return append_entries_t(t, true);
-  
 }
 
 // @brief load persistent state
-bool Agent::load () {
-  DatabaseFeature* database = dynamic_cast<DatabaseFeature*>(
-    ApplicationServer::lookupFeature("Database"));
+bool Agent::load() {
+  DatabaseFeature* database = 
+    ApplicationServer::getFeature<DatabaseFeature>("Database");
 
   auto vocbase = database->vocbase();
 
@@ -310,7 +310,9 @@ bool Agent::load () {
   _readDB.start(this);
 
   LOG_TOPIC(INFO, Logger::AGENCY) << "Starting constituent personality.";
-  _constituent.start(vocbase);
+  auto queryRegistry = QueryRegistryFeature::QUERY_REGISTRY;
+  TRI_ASSERT(queryRegistry != nullptr);
+  _constituent.start(vocbase, queryRegistry);
 
   if (_config.supervision) {
     LOG_TOPIC(INFO, Logger::AGENCY) << "Starting cluster sanity facilities";

arangod/Agency/Constituent.cpp

@@ -370,8 +370,10 @@ void Constituent::beginShutdown() {
   Thread::beginShutdown();
 }
 
-bool Constituent::start (TRI_vocbase_t* vocbase) {
+bool Constituent::start(TRI_vocbase_t* vocbase,
+                        aql::QueryRegistry* queryRegistry) {
   _vocbase = vocbase;
+  _queryRegistry = queryRegistry;
   return Thread::start();
 }
 

arangod/Agency/Constituent.h

@@ -96,9 +96,9 @@ public:
   size_t size() const;
 
   /// @brief Orderly shutdown of thread
-  void beginShutdown () override;
+  void beginShutdown() override;
 
-  bool start (TRI_vocbase_t* vocbase);
+  bool start(TRI_vocbase_t* vocbase, aql::QueryRegistry*);
 
 private:
 

arangod/Aql/ExecutionEngine.cpp

@@ -821,6 +821,8 @@ ExecutionEngine* ExecutionEngine::instantiateFromPlan(
   bool const isCoordinator =
       arangodb::ServerState::instance()->isCoordinator(role);
   bool const isDBServer = arangodb::ServerState::instance()->isDBServer(role);
+      
+  TRI_ASSERT(queryRegistry != nullptr);
 
   ExecutionEngine* engine = nullptr;
 
@@ -836,7 +838,6 @@ ExecutionEngine* ExecutionEngine::instantiateFromPlan(
 
     if (isCoordinator) {
       // instantiate the engine on the coordinator
-
       auto inst =
           std::make_unique<CoordinatorInstanciator>(query, queryRegistry);
       plan->root()->walk(inst.get());

arangod/Aql/Query.cpp

@@ -391,6 +391,8 @@ void Query::registerWarning(int code, char const* details) {
 /// to be able to only prepare a query from VelocyPack and then store it in the
 /// QueryRegistry.
 QueryResult Query::prepare(QueryRegistry* registry) {
+  TRI_ASSERT(registry != nullptr);
+
   try {
     init();
     enterState(PARSING);
@@ -513,6 +515,8 @@ QueryResult Query::prepare(QueryRegistry* registry) {
 
 /// @brief execute an AQL query
 QueryResult Query::execute(QueryRegistry* registry) {
+  TRI_ASSERT(registry != nullptr);
+
   std::unique_ptr<AqlWorkStack> work;
 
   try {

arangod/Cluster/ClusterFeature.cpp

@@ -62,6 +62,7 @@ ClusterFeature::ClusterFeature(application_features::ApplicationServer* server)
   startsAfter("Dispatcher");
   startsAfter("Scheduler");
   startsAfter("V8Dealer");
+  startsAfter("Database");
 }
 
 ClusterFeature::~ClusterFeature() {

arangod/RestServer/CheckVersionFeature.cpp

@@ -68,18 +68,15 @@ void CheckVersionFeature::validateOptions(
 
   ApplicationServer::forceDisableFeatures(_nonServerFeatures);
 
-  LoggerFeature* logger =
-      dynamic_cast<LoggerFeature*>(ApplicationServer::lookupFeature("Logger"));
+  LoggerFeature* logger = ApplicationServer::getFeature<LoggerFeature>("Logger");
   logger->disableThreaded();
 
-  DatabaseFeature* database = dynamic_cast<DatabaseFeature*>(
-      ApplicationServer::lookupFeature("Database"));
+  DatabaseFeature* database = ApplicationServer::getFeature<DatabaseFeature>("Database");
   database->disableReplicationApplier();
   database->disableCompactor();
   database->enableCheckVersion();
 
-  V8DealerFeature* v8dealer = dynamic_cast<V8DealerFeature*>(
-      ApplicationServer::lookupFeature("V8Dealer"));
+  V8DealerFeature* v8dealer = ApplicationServer::getFeature<V8DealerFeature>("V8Dealer");
 
   v8dealer->setNumberContexts(1);
 }

arangod/RestServer/DatabaseFeature.cpp

@@ -182,23 +182,25 @@ void DatabaseFeature::updateContexts() {
   }
 
   auto queryRegistry = QueryRegistryFeature::QUERY_REGISTRY;
+  TRI_ASSERT(queryRegistry != nullptr);
+
   auto server = DatabaseServerFeature::SERVER;
+  TRI_ASSERT(server != nullptr);
+
   auto vocbase = _vocbase;
 
-  V8DealerFeature* dealer = dynamic_cast<V8DealerFeature*>(
-      ApplicationServer::lookupFeature("V8Dealer"));
-
-  if (dealer != nullptr) {
-    dealer->defineContextUpdate(
-        [queryRegistry, server, vocbase](
-            v8::Isolate* isolate, v8::Handle<v8::Context> context, size_t i) {
-          TRI_InitV8VocBridge(isolate, context, queryRegistry, server, vocbase,
-                              i);
-          TRI_InitV8Queries(isolate, context);
-          TRI_InitV8Cluster(isolate, context);
-        },
-        vocbase);
-  }
+  V8DealerFeature* dealer = 
+      ApplicationServer::getFeature<V8DealerFeature>("V8Dealer");
+  
+  dealer->defineContextUpdate(
+      [queryRegistry, server, vocbase](
+          v8::Isolate* isolate, v8::Handle<v8::Context> context, size_t i) {
+        TRI_InitV8VocBridge(isolate, context, queryRegistry, server, vocbase,
+                            i);
+        TRI_InitV8Queries(isolate, context);
+        TRI_InitV8Cluster(isolate, context);
+      },
+      vocbase);
 }
 
 void DatabaseFeature::shutdownCompactor() {

arangod/RestServer/QueryRegistryFeature.cpp

@@ -71,15 +71,18 @@ void QueryRegistryFeature::prepare() {
   std::pair<std::string, size_t> cacheProperties{_queryCacheMode,
                                                  _queryCacheEntries};
   arangodb::aql::QueryCache::instance()->setProperties(cacheProperties);
+  
+  // create the query registery
+  _queryRegistry.reset(new aql::QueryRegistry());
+  QUERY_REGISTRY = _queryRegistry.get();
 }
 
 void QueryRegistryFeature::start() {
-  // create the query registery
-  _queryRegistry.reset(new aql::QueryRegistry());
   DatabaseServerFeature::SERVER->_queryRegistry = _queryRegistry.get();
 }
 
 void QueryRegistryFeature::stop() {
   // clear the query registery
   DatabaseServerFeature::SERVER->_queryRegistry = nullptr;
+  // TODO: reset QUERY_REGISTRY as well?
 }

arangod/RestServer/ServerFeature.cpp

@@ -130,17 +130,17 @@ void ServerFeature::validateOptions(std::shared_ptr<ProgramOptions>) {
                                         "RestServer", "Scheduler", "Ssl",
                                         "Supervisor"});
 
-    DatabaseFeature* database = dynamic_cast<DatabaseFeature*>(
-        ApplicationServer::lookupFeature("Database"));
+    DatabaseFeature* database = 
+        ApplicationServer::getFeature<DatabaseFeature>("Database");
     database->disableReplicationApplier();
 
-    StatisticsFeature* statistics = dynamic_cast<StatisticsFeature*>(
-        ApplicationServer::lookupFeature("Statistics"));
+    StatisticsFeature* statistics = 
+        ApplicationServer::getFeature<StatisticsFeature>("Statistics");
     statistics->disableStatistics();
   }
 
-  V8DealerFeature* v8dealer = dynamic_cast<V8DealerFeature*>(
-      ApplicationServer::lookupFeature("V8Dealer"));
+  V8DealerFeature* v8dealer = 
+      ApplicationServer::getFeature<V8DealerFeature>("V8Dealer");
 
   if (_operationMode == OperationMode::MODE_SCRIPT ||
       _operationMode == OperationMode::MODE_UNITTESTS) {
@@ -162,8 +162,8 @@ void ServerFeature::validateOptions(std::shared_ptr<ProgramOptions>) {
 
 void ServerFeature::start() {
   if (_operationMode != OperationMode::MODE_CONSOLE && _restServer) {
-    auto scheduler = dynamic_cast<SchedulerFeature*>(
-        ApplicationServer::lookupFeature("Scheduler"));
+    auto scheduler = 
+        ApplicationServer::getFeature<SchedulerFeature>("Scheduler");
 
     if (scheduler != nullptr) {
       scheduler->buildControlCHandler();
@@ -236,8 +236,8 @@ std::string ServerFeature::operationModeString(OperationMode mode) {
 }
 
 int ServerFeature::runUnitTests() {
-  DatabaseFeature* database = dynamic_cast<DatabaseFeature*>(
-      ApplicationServer::lookupFeature("Database"));
+  DatabaseFeature* database = 
+      ApplicationServer::getFeature<DatabaseFeature>("Database");
   V8Context* context =
       V8DealerFeature::DEALER->enterContext(database->vocbase(), true);
 
@@ -295,8 +295,8 @@ int ServerFeature::runUnitTests() {
 int ServerFeature::runScript() {
   bool ok = false;
 
-  DatabaseFeature* database = dynamic_cast<DatabaseFeature*>(
-      ApplicationServer::lookupFeature("Database"));
+  DatabaseFeature* database = 
+      ApplicationServer::getFeature<DatabaseFeature>("Database");
   V8Context* context =
       V8DealerFeature::DEALER->enterContext(database->vocbase(), true);
 

arangod/V8Server/V8DealerFeature.cpp

@@ -101,6 +101,7 @@ V8DealerFeature::V8DealerFeature(
   startsAfter("Action");
   startsAfter("Database");
   startsAfter("Dispatcher");
+  startsAfter("QueryRegistry");
   startsAfter("Scheduler");
   startsAfter("V8Platform");
   startsAfter("WorkMonitor");
@@ -178,8 +179,8 @@ void V8DealerFeature::start() {
 
   // try to guess a suitable number of contexts
   if (0 == _nrContexts && 0 == _forceNrContexts) {
-    DispatcherFeature* dispatcher = dynamic_cast<DispatcherFeature*>(
-        ApplicationServer::lookupFeature("Dispatcher"));
+    DispatcherFeature* dispatcher = 
+        ApplicationServer::getFeature<DispatcherFeature>("Dispatcher");
 
     if (dispatcher != nullptr) {
       _nrContexts = dispatcher->concurrency();
@@ -215,8 +216,8 @@ void V8DealerFeature::start() {
 
   applyContextUpdates();
 
-  DatabaseFeature* database = dynamic_cast<DatabaseFeature*>(
-      ApplicationServer::lookupFeature("Database"));
+  DatabaseFeature* database = 
+      ApplicationServer::getFeature<DatabaseFeature>("Database");
 
   loadJavascript(database->vocbase(), "server/initialize.js");
 

arangod/V8Server/v8-vocbase.cpp

@@ -3447,6 +3447,7 @@ void TRI_InitV8VocBridge(v8::Isolate* isolate, v8::Handle<v8::Context> context,
   static_cast<V8TransactionContext*>(v8g->_transactionContext)->makeGlobal();
 
   // register the query registry
+  TRI_ASSERT(queryRegistry != nullptr);
   v8g->_queryRegistry = queryRegistry;
 
   // register the server

arangod/VocBase/server.cpp

@@ -1071,8 +1071,7 @@ static void DatabaseManager(void* data) {
 
       usleep(DATABASE_MANAGER_INTERVAL);
       // The following is only necessary after a wait:
-      auto queryRegistry =
-          static_cast<arangodb::aql::QueryRegistry*>(server->_queryRegistry);
+      auto queryRegistry = server->_queryRegistry.load();
 
       if (queryRegistry != nullptr) {
         queryRegistry->expireQueries();
@@ -1092,8 +1091,7 @@ static void DatabaseManager(void* data) {
         for (auto& p : theLists->_coordinatorDatabases) {
           TRI_vocbase_t* vocbase = p.second;
           TRI_ASSERT(vocbase != nullptr);
-          auto cursorRepository = static_cast<arangodb::CursorRepository*>(
-              vocbase->_cursorRepository);
+          auto cursorRepository = vocbase->_cursorRepository;
 
           try {
             cursorRepository->garbageCollect(false);