Clean up lua stack and weak pointers

src/engine/moduleengine.cpp

@@ -30,6 +30,7 @@
 
 #include <ghoul/logging/logmanager.h>
 #include <ghoul/misc/dictionary.h>
+#include <ghoul/misc/assert.h>
 
 #include <algorithm>
 

src/engine/moduleengine_lua.inl

@@ -57,6 +57,7 @@ int isLoaded(lua_State* L) {
     else
         lua_pushboolean(L, 0);
 
+    ghoul_assert(lua_gettop(L) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 

src/engine/openspaceengine_lua.inl

@@ -41,6 +41,7 @@ int toggleShutdown(lua_State* L) {
 
     OsEng.toggleShutdownMode();
 
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -58,6 +59,7 @@ int writeDocumentation(lua_State* L) {
     OsEng.writeStaticDocumentation();
     OsEng.writeSceneDocumentation();
 
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -115,10 +117,13 @@ int addVirtualProperty(lua_State* L) {
         );
     }
     else {
+        lua_settop(L, 0);
         return luaL_error(L, "Unknown property type '%s'", type.c_str());
     }
 
+    lua_settop(L, 0);
     OsEng.virtualPropertyManager().addProperty(std::move(prop));
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -134,8 +139,10 @@ int removeVirtualProperty(lua_State* L) {
     }
 
     const std::string name = lua_tostring(L, -1);
+    lua_settop(L, 0);
     properties::Property* p = OsEng.virtualPropertyManager().property(name);
     OsEng.virtualPropertyManager().removeProperty(p);
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -146,8 +153,8 @@ int removeVirtualProperty(lua_State* L) {
 */
 int removeAllVirtualProperties(lua_State* L) {
     const int nArguments = lua_gettop(L);
-    if (nArguments != 1) {
-        return luaL_error(L, "Expected %i arguments, got %i", 1, nArguments);
+    if (nArguments != 0) {
+        return luaL_error(L, "Expected %i arguments, got %i", 0, nArguments);
     }
 
     std::vector<properties::Property*> ps = OsEng.virtualPropertyManager().properties();
@@ -155,6 +162,8 @@ int removeAllVirtualProperties(lua_State* L) {
         OsEng.virtualPropertyManager().removeProperty(p);
         delete p;
     }
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -171,6 +180,7 @@ int addTag(lua_State* L) {
 
     const std::string uri = lua_tostring(L, -2);
     const std::string tag = lua_tostring(L, -1);
+    lua_settop(L, 0);
 
     SceneGraphNode* node = OsEng.renderEngine().scene()->sceneGraphNode(uri);
     if (!node) {
@@ -179,6 +189,7 @@ int addTag(lua_State* L) {
 
     node->addTag(std::move(tag));
 
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -195,6 +206,7 @@ int removeTag(lua_State* L) {
 
     const std::string uri = lua_tostring(L, -2);
     const std::string tag = lua_tostring(L, -1);
+    lua_settop(L, 0);
 
     SceneGraphNode* node = OsEng.renderEngine().scene()->sceneGraphNode(uri);
     if (!node) {
@@ -203,6 +215,7 @@ int removeTag(lua_State* L) {
 
     node->removeTag(tag);
 
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -217,6 +230,7 @@ int downloadFile(lua_State* L) {
         return luaL_error(L, "Expected %i arguments, got %i", 2, nArguments);
     std::string uri = luaL_checkstring(L, -2);
     std::string savePath = luaL_checkstring(L, -1);
+    lua_settop(L, 0);
 
     const std::string _loggerCat = "OpenSpaceEngine";
     LINFO("Downloading file from " << uri);
@@ -229,7 +243,9 @@ int downloadFile(lua_State* L) {
             errorMsg += ": " + future->errorMessage;
         return luaL_error(L, errorMsg.c_str());
     }
-    return 1;
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
+    return 0;
 }
 
 } // namespace luascriptfunctions

src/engine/wrapper/windowwrapper.cpp

@@ -41,6 +41,8 @@ int setSynchronization(lua_State* L) {
 
     bool b = lua_toboolean(L, -1) != 0;
     OsEng.windowWrapper().setSynchronization(b);
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 

src/interaction/keybindingmanager_lua.inl

@@ -69,6 +69,8 @@ int bindKey(lua_State* L) {
         std::move(documentation)
     );
 
+    lua_settop(L, 0);
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -115,6 +117,8 @@ int bindKeyLocal(lua_State* L) {
         std::move(documentation)
         );
 
+    lua_settop(L, 0);
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -131,6 +135,7 @@ int getKeyBindings(lua_State* L) {
     }
 
     std::string key = luaL_checkstring(L, -1);
+    lua_settop(L, 0);
 
     using KeyInformation = interaction::KeyBindingManager::KeyInformation;
 
@@ -153,6 +158,8 @@ int getKeyBindings(lua_State* L) {
         lua_settable(L, -3);
         ++i;
     }
+
+    ghoul_assert(lua_gettop(L) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 
@@ -168,9 +175,11 @@ int clearKey(lua_State* L) {
     }
 
     std::string key = luaL_checkstring(L, -1);
+    lua_settop(L, 0);
 
     OsEng.keyBindingManager().removeKeyBinding(key);
 
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -187,6 +196,7 @@ int clearKeys(lua_State* L) {
 
     OsEng.keyBindingManager().resetKeyBindings();
 
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 

src/interaction/navigationhandler_lua.inl

@@ -33,12 +33,14 @@ int restoreCameraStateFromFile(lua_State* L) {
     }
 
     std::string cameraStateFilePath = luaL_checkstring(L, -1);
+    lua_settop(L, 0);
 
     if (cameraStateFilePath.empty()) {
         return luaL_error(L, "filepath string is empty");
     }
 
     OsEng.navigationHandler().restoreCameraStateFromFile(cameraStateFilePath);
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -53,8 +55,12 @@ int setCameraState(lua_State* L) {
         ghoul::lua::luaDictionaryFromState(L, dictionary);
         OsEng.navigationHandler().setCameraStateFromDictionary(dictionary);
     } catch (const ghoul::RuntimeError& e) {
+        lua_settop(L, 0);
         return luaL_error(L, "Could not set camera state: %s", e.what());
     }
+
+    lua_settop(L, 0);
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -67,12 +73,14 @@ int saveCameraStateToFile(lua_State* L) {
     }
 
     std::string cameraStateFilePath = luaL_checkstring(L, -1);
+    lua_settop(L, 0);
 
     if (cameraStateFilePath.empty()) {
         return luaL_error(L, "filepath string is empty");
     }
 
     OsEng.navigationHandler().saveCameraStateToFile(cameraStateFilePath);
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -85,6 +93,7 @@ int resetCameraDirection(lua_State* L) {
     }
 
     OsEng.navigationHandler().resetCameraDirection();
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 

src/mission/missionmanager_lua.inl

@@ -36,6 +36,8 @@ int loadMission(lua_State* L) {
     }
     std::string name = MissionManager::ref().loadMission(absPath(missionFileName));
     lua_pushstring(L, name.c_str());
+
+    ghoul_assert(lua_gettop(L) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 
@@ -55,6 +57,8 @@ int unloadMission(lua_State* L) {
     }
 
     MissionManager::ref().unloadMission(missionName);
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -72,6 +76,8 @@ int hasMission(lua_State* L) {
     bool hasMission = MissionManager::ref().hasMission(missionName);
 
     lua_pushboolean(L, hasMission);
+
+    ghoul_assert(lua_gettop(L) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 
@@ -86,6 +92,8 @@ int setCurrentMission(lua_State* L) {
         return luaL_error(L, "Mission name is empty");
     }
     MissionManager::ref().setCurrentMission(missionName);
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 

src/network/parallelconnection_lua.inl

@@ -31,6 +31,8 @@ int connect(lua_State* L) {
     if (OsEng.windowWrapper().isMaster()) {
         OsEng.parallelConnection().clientConnect();
     }
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -41,6 +43,8 @@ int disconnect(lua_State* L) {
     if (OsEng.windowWrapper().isMaster()) {
         OsEng.parallelConnection().signalDisconnect();
     }
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -51,6 +55,8 @@ int requestHostship(lua_State* L) {
     if (OsEng.windowWrapper().isMaster()) {
         OsEng.parallelConnection().requestHostship();
     }
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -61,6 +67,8 @@ int resignHostship(lua_State* L) {
     if (OsEng.windowWrapper().isMaster()) {
         OsEng.parallelConnection().resignHostship();
     }
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 

src/rendering/dashboard.cpp

@@ -27,6 +27,7 @@
 #include <openspace/rendering/dashboarditem.h>
 #include <openspace/scripting/scriptengine.h>
 
+#include <ghoul/misc/assert.h>
 #include "dashboard_lua.inl"
 
 namespace openspace {

src/rendering/dashboard_lua.inl

@@ -46,10 +46,14 @@ int addDashboardItem(lua_State* L) {
         }
         catch (const ghoul::lua::LuaFormatException& e) {
             LERRORC("addDashboardItem", e.what());
+            lua_settop(L, 0);
             return 0;
         }
+        lua_settop(L, 0);
 
         OsEng.dashboard().addDashboardItem(DashboardItem::createFromDictionary(d));
+
+        ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
         return 0;
     }
     else {
@@ -68,6 +72,8 @@ int removeDashboardItems(lua_State* L) {
     }
 
     OsEng.dashboard().removeDashboardItems();
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 

src/rendering/renderengine_lua.inl

@@ -41,6 +41,8 @@ int setRenderer(lua_State* L) {
     }
     std::string r = lua_tostring(L, -1);
     OsEng.renderEngine().setRendererFromString(r);
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -61,6 +63,8 @@ int toggleFade(lua_State* L) {
     int direction = OsEng.renderEngine().globalBlackOutFactor() == fadedIn ? -1 : 1;
 
     OsEng.renderEngine().startFading(direction, static_cast<float>(t));
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -78,6 +82,8 @@ int fadeIn(lua_State* L) {
     double t = luaL_checknumber(L, -1);
 
     OsEng.renderEngine().startFading(1, static_cast<float>(t));
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 /**
@@ -94,6 +100,8 @@ int fadeOut(lua_State* L) {
     double t = luaL_checknumber(L, -1);
 
     OsEng.renderEngine().startFading(-1, static_cast<float>(t));
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -119,6 +127,7 @@ int addScreenSpaceRenderable(lua_State* L) {
     );
     OsEng.renderEngine().addScreenSpaceRenderable(s);
 
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -140,11 +149,13 @@ int removeScreenSpaceRenderable(lua_State* L) {
             "removeScreenSpaceRenderable",
             errorLocation(L) << "Could not find ScreenSpaceRenderable '" << name << "'"
         );
+        ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
         return 0;
     }
 
     OsEng.renderEngine().removeScreenSpaceRenderable(s);
 
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 

src/scene/asset.cpp

@@ -27,6 +27,7 @@
 
 #include <ghoul/logging/logmanager.h>
 
+#include <iterator>
 #include <algorithm>
 #include <unordered_set>
 
@@ -185,10 +186,10 @@ void Asset::clearSynchronizations() {
     for (const SynchronizationWatcher::WatchHandle& h : _syncWatches) {
         _synchronizationWatcher->unwatchSynchronization(h);
     }
+    _syncWatches.clear();
 }
 
-void Asset::syncStateChanged(ResourceSynchronization::State state)
-{
+void Asset::syncStateChanged(ResourceSynchronization::State state) {
     if (state == ResourceSynchronization::State::Resolved) {
         if (!isSynchronized() && isSyncResolveReady()) {
             setState(State::SyncResolved);
@@ -274,28 +275,39 @@ bool Asset::isSyncingOrResolved() const {
         s == State::InitializationFailed;
 }
 
-bool Asset::hasLoadedParent() const {
-    for (const auto& p : _requiringAssets) {
-        std::shared_ptr<Asset> parent = p.lock();
-        if (!parent) {
-            continue;
-        }
-        if (parent->isLoaded()) {
-            return true;
+bool Asset::hasLoadedParent() {
+    {
+        std::vector<std::weak_ptr<Asset>>::iterator it = _requiringAssets.begin();
+        while (it != _requiringAssets.end()) {
+            std::shared_ptr<Asset> parent = it->lock();
+            if (!parent) {
+                it = _requiringAssets.erase(it);
+                continue;
+            }
+            if (parent->isLoaded()) {
+                return true;
+            }
+            ++it;
         }
     }
-    for (const auto& p : _requestingAssets) {
-        std::shared_ptr<Asset> parent = p.lock();
-        if (!parent) {
-            continue;
-        }
-        if (parent->isLoaded()) {
-            return true;
-        }
-        if (parent->hasLoadedParent()) {
-            return true;
+    {
+        std::vector<std::weak_ptr<Asset>>::iterator it = _requestingAssets.begin();
+        while (it != _requestingAssets.end()) {
+            std::shared_ptr<Asset> parent = it->lock();
+            if (!parent) {
+                it = _requestingAssets.erase(it);
+                continue;
+            }
+            if (parent->isLoaded()) {
+                return true;
+            }
+            if (parent->hasLoadedParent()) {
+                return true;
+            }
+            ++it;
         }
     }
+
     return false;
 }
 

src/scene/assetloader.cpp

@@ -145,6 +145,8 @@ void AssetLoader::setUpAssetLuaTable(Asset* asset) {
     |- onDeinitialize
     */
 
+    int top = lua_gettop(*_luaState);
+
     // Push the global table of AssetInfos to the lua stack.
     lua_rawgeti(*_luaState, LUA_REGISTRYINDEX, _assetsTableRef);
     int globalTableIndex = lua_gettop(*_luaState);
@@ -227,9 +229,11 @@ void AssetLoader::setUpAssetLuaTable(Asset* asset) {
     // Extend global asset info table (pushed to the lua stack earlier)
     // with this AssetInfo table
     lua_setfield(*_luaState, globalTableIndex, asset->id().c_str());
+    lua_settop(*_luaState, top);
 }
 
 void AssetLoader::tearDownAssetLuaTable(Asset* asset) {
+    int top = lua_gettop(*_luaState);
     // Push the global table of AssetInfos to the lua stack.
     lua_rawgeti(*_luaState, LUA_REGISTRYINDEX, _assetsTableRef);
     int globalTableIndex = lua_gettop(*_luaState);
@@ -238,9 +242,11 @@ void AssetLoader::tearDownAssetLuaTable(Asset* asset) {
 
     // Clear entry from global asset table (pushed to the lua stack earlier)
     lua_setfield(*_luaState, globalTableIndex, asset->id().c_str());
+    lua_settop(*_luaState, top);
 }
 
 bool AssetLoader::loadAsset(std::shared_ptr<Asset> asset) {
+    int top = lua_gettop(*_luaState);
     std::shared_ptr<Asset> parentAsset = _currentAsset;
 
     setCurrentAsset(asset);
@@ -251,6 +257,7 @@ bool AssetLoader::loadAsset(std::shared_ptr<Asset> asset) {
     if (!FileSys.fileExists(asset->assetFilePath())) {
         LERROR("Could not load asset '" << asset->assetFilePath() <<
                "': File does not exist.");
+        lua_settop(*_luaState, top);
         return false;
     }
 
@@ -258,9 +265,11 @@ bool AssetLoader::loadAsset(std::shared_ptr<Asset> asset) {
         ghoul::lua::runScriptFile(*_luaState, asset->assetFilePath());
     } catch (const ghoul::lua::LuaRuntimeException& e) {
         LERROR("Could not load asset '" << asset->assetFilePath() << "': " << e.message);
+        lua_settop(*_luaState, top);
         return false;
     }
 
+    lua_settop(*_luaState, top);
     return true;
 }
 
@@ -384,6 +393,7 @@ int AssetLoader::onInitializeLua(Asset* asset) {
     SCRIPT_CHECK_ARGUMENTS("onInitialize", *_luaState, 1, nArguments);
     int referenceIndex = luaL_ref(*_luaState, LUA_REGISTRYINDEX);
     _onInitializationFunctionRefs[asset].push_back(referenceIndex);
+    lua_settop(*_luaState, 0);
     return 0;
 }
 
@@ -392,6 +402,7 @@ int AssetLoader::onDeinitializeLua(Asset* asset) {
     SCRIPT_CHECK_ARGUMENTS("onDeinitialize", *_luaState, 1, nArguments);
     int referenceIndex = luaL_ref(*_luaState, LUA_REGISTRYINDEX);
     _onDeinitializationFunctionRefs[asset].push_back(referenceIndex);
+    lua_settop(*_luaState, 0);
     return 0;
 }
 
@@ -401,7 +412,7 @@ int AssetLoader::onInitializeDependencyLua(Asset* dependant, Asset* dependency)
     int referenceIndex = luaL_ref(*_luaState, LUA_REGISTRYINDEX);
     _onDependencyInitializationFunctionRefs[dependant][dependency]
         .push_back(referenceIndex);
-
+    lua_settop(*_luaState, 0);
     return 0;
 }
 
@@ -411,7 +422,7 @@ int AssetLoader::onDeinitializeDependencyLua(Asset* dependant, Asset* dependency
     int referenceIndex = luaL_ref(*_luaState, LUA_REGISTRYINDEX);
     _onDependencyDeinitializationFunctionRefs[dependant][dependency]
         .push_back(referenceIndex);
-
+    lua_settop(*_luaState, 0);
     return 0;
 }
 
@@ -547,7 +558,10 @@ int AssetLoader::localResourceLua(Asset* asset) {
     std::string resourceName = luaL_checkstring(*_luaState, -1);
     std::string resolved = asset->resolveLocalResource(resourceName);
 
+    lua_settop(*_luaState, 0);
     lua_pushstring(*_luaState, resolved.c_str());
+
+    ghoul_assert(lua_gettop(*_luaState) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 
@@ -565,17 +579,23 @@ int AssetLoader::syncedResourceLua(Asset* asset) {
 
     asset->addSynchronization(sync);
 
+    lua_settop(*_luaState, 0);
     lua_pushstring(*_luaState, absolutePath.c_str());
+
+    ghoul_assert(lua_gettop(*_luaState) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 
 void AssetLoader::setCurrentAsset(std::shared_ptr<Asset> asset) {
+    int top = lua_gettop(*_luaState);
+
     _currentAsset = asset;
     // Set `asset` lua global to point to the current asset table
 
     if (asset == _rootAsset) {
         lua_pushnil(*_luaState);
         lua_setglobal(*_luaState, AssetGlobalVariableName);
+        lua_settop(*_luaState, top);
         return;
     }
 
@@ -583,6 +603,8 @@ void AssetLoader::setCurrentAsset(std::shared_ptr<Asset> asset) {
     lua_getfield(*_luaState, -1, asset->id().c_str());
     lua_getfield(*_luaState, -1, AssetTableName);
     lua_setglobal(*_luaState, AssetGlobalVariableName);
+
+    lua_settop(*_luaState, top);
 }
 
 int AssetLoader::requireLua(Asset* dependant) {
@@ -590,6 +612,7 @@ int AssetLoader::requireLua(Asset* dependant) {
     SCRIPT_CHECK_ARGUMENTS("require", *_luaState, 1, nArguments);
 
     std::string assetName = luaL_checkstring(*_luaState, 1);
+    lua_settop(*_luaState, 0);
 
     std::shared_ptr<Asset> dependency = require(assetName);
 
@@ -614,6 +637,12 @@ int AssetLoader::requireLua(Asset* dependant) {
 
     lua_pushvalue(*_luaState, exportsTableIndex);
     lua_pushvalue(*_luaState, dependencyTableIndex);
+
+    lua_replace(*_luaState, 2);
+    lua_replace(*_luaState, 1);
+    lua_settop(*_luaState, 2);
+
+    ghoul_assert(lua_gettop(*_luaState) == 2, "Incorrect number of items left on stack");
     return 2;
 }
 
@@ -622,6 +651,7 @@ int AssetLoader::requestLua(Asset* parent) {
     SCRIPT_CHECK_ARGUMENTS("request", *_luaState, 1, nArguments);
 
     std::string assetName = luaL_checkstring(*_luaState, 1);
+    lua_settop(*_luaState, 0);
 
     std::shared_ptr<Asset> child = request(assetName);
 
@@ -635,6 +665,11 @@ int AssetLoader::requestLua(Asset* parent) {
     int dependencyTableIndex = lua_gettop(*_luaState);
 
     lua_pushvalue(*_luaState, dependencyTableIndex);
+
+    lua_replace(*_luaState, 1);
+    lua_settop(*_luaState, 1);
+
+    ghoul_assert(lua_gettop(*_luaState) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 
@@ -647,7 +682,9 @@ int AssetLoader::existsLua(Asset* asset) {
     ghoul::filesystem::Directory directory = currentDirectory();
     std::string path = generateAssetPath(directory, assetName);
 
+    lua_settop(*_luaState, 0);
     lua_pushboolean(*_luaState, FileSys.fileExists(path));
+    ghoul_assert(lua_gettop(*_luaState) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 
@@ -665,10 +702,15 @@ int AssetLoader::exportAssetLua(Asset* asset) {
     // push the second argument
     lua_pushvalue(*_luaState, 2);
     lua_setfield(*_luaState, exportsTableIndex, exportName.c_str());
+
+    lua_settop(*_luaState, 0);
+    ghoul_assert(lua_gettop(*_luaState) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
 void AssetLoader::addLuaDependencyTable(Asset* dependant, Asset* dependency) {
+    int top = lua_gettop(*_luaState);
+
     const std::string dependantId = dependant->id();
     const std::string dependencyId = dependency->id();
 
@@ -701,6 +743,8 @@ void AssetLoader::addLuaDependencyTable(Asset* dependant, Asset* dependency) {
 
     // Register the dependant table on the imported asset's dependants table.
     lua_setfield(*_luaState, dependantsTableIndex, dependantId.c_str());
+
+    lua_settop(*_luaState, top);
 }
 
 void AssetLoader::addAssetListener(AssetListener* listener) {

src/scene/scene_lua.inl

@@ -320,10 +320,13 @@ int property_getValue(lua_State* L) {
             "property_getValue",
             errorLocation(L) << "Property with URL '" << uri << "' was not found"
         );
+        ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
         return 0;
-    }
-    else
+    } else {
         prop->getLuaValue(L);
+    }
+
+    ghoul_assert(lua_gettop(L) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 
@@ -340,6 +343,7 @@ int loadScene(lua_State* L) {
     std::string sceneFile = luaL_checkstring(L, -1);
     OsEng.scheduleLoadSingleAsset(sceneFile);
 
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -377,6 +381,9 @@ int addSceneGraphNode(lua_State* L) {
     } catch (const ghoul::RuntimeError& e) {
         return luaL_error(L, "Error loading scene graph node: %s", e.what());
     }
+
+    lua_settop(L, 0);
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -405,7 +412,10 @@ int removeSceneGraphNode(lua_State* L) {
     }
     node->deinitializeGL();
     parent->detachChild(*node);
-    return 1;
+
+    lua_settop(L, 0);
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
+    return 0;
 }
 
 
@@ -416,7 +426,10 @@ int hasSceneGraphNode(lua_State* L) {
     std::string nodeName = luaL_checkstring(L, -1);
     SceneGraphNode* node = OsEng.renderEngine().scene()->sceneGraphNode(nodeName);
 
+    lua_settop(L, 0);
     lua_pushboolean(L, node != nullptr);
+
+    ghoul_assert(lua_gettop(L) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 

src/scripting/scriptengine.cpp

@@ -81,6 +81,8 @@ void ScriptEngine::deinitialize() {
 
 void ScriptEngine::initializeLuaState(lua_State* state) {
     LDEBUG("Create openspace base library");
+    int top = lua_gettop(state);
+
     lua_newtable(state);
     lua_setglobal(state, OpenSpaceLibraryName.c_str());
 
@@ -88,6 +90,8 @@ void ScriptEngine::initializeLuaState(lua_State* state) {
     for (LuaLibrary& lib : _registeredLibraries) {
         registerLuaLibrary(state, lib);
     }
+
+    lua_settop(state, top);
 }
 
 ghoul::lua::LuaState * ScriptEngine::luaState() {
@@ -462,6 +466,7 @@ void ScriptEngine::remapPrintFunction() {
 
 bool ScriptEngine::registerLuaLibrary(lua_State* state, LuaLibrary& library) {
     ghoul_assert(state, "State must not be nullptr");
+    int top = lua_gettop(state);
 
     lua_getglobal(state, OpenSpaceLibraryName.c_str());
     if (library.name.empty()) {
@@ -471,6 +476,7 @@ bool ScriptEngine::registerLuaLibrary(lua_State* state, LuaLibrary& library) {
     else {
         const bool allowed = isLibraryNameAllowed(state, library.name);
         if (!allowed) {
+            lua_settop(state, top);
             return false;
         }
 
@@ -492,6 +498,8 @@ bool ScriptEngine::registerLuaLibrary(lua_State* state, LuaLibrary& library) {
         // Pop the table
         lua_pop(state, 1);
     }
+
+    lua_settop(state, top);
     return true;
 }
 

src/scripting/scriptengine_lua.inl

@@ -71,6 +71,8 @@ int walkCommon(lua_State* L, Func func) {
         );
     }
 
+    lua_settop(L, 0);
+
     // Copy values into the lua_State
     lua_newtable(L);
 
@@ -79,6 +81,7 @@ int walkCommon(lua_State* L, Func func) {
         lua_rawseti(L, -2, i + 1);
     }
 
+    ghoul_assert(lua_gettop(L) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 } // namespace
@@ -115,6 +118,7 @@ int printInternal(ghoul::logging::LogLevel level, lua_State* L) {
             LOGC(level, "print", lua_tostring(L, -1));
             break;
     }
+    lua_settop(L, 0);
     return 0;
 }
 
@@ -197,6 +201,8 @@ int absolutePath(lua_State* L) {
     }
 
     std::string path = luaL_checkstring(L, -1);
+    lua_settop(L, 0);
+
     path = absPath(path);
     //path = FileSys.convertPathSeparator(path, '/');
     lua_pushstring(L, path.c_str());
@@ -217,6 +223,7 @@ int setPathToken(lua_State* L) {
 
     const std::string path = luaL_checkstring(L, -1);
     const std::string pathToken = luaL_checkstring(L, -2);
+    lua_settop(L, 0);
     FileSys.registerPathToken(
         pathToken,
         path,
@@ -238,6 +245,8 @@ int fileExists(lua_State* L) {
 
     const std::string file = luaL_checkstring(L, -1);
     const bool e = FileSys.fileExists(absPath(file));
+
+    lua_settop(L, 0);
     lua_pushboolean(L, (e ? 1 : 0));
     return 1;
 }
@@ -255,6 +264,8 @@ int directoryExists(lua_State* L) {
 
     const std::string file = luaL_checkstring(L, -1);
     const bool e = FileSys.directoryExists(absPath(file));
+
+    lua_settop(L, 0);
     lua_pushboolean(L, (e ? 1 : 0));
     return 1;
 }
@@ -315,6 +326,8 @@ int directoryForPath(lua_State* L) {
 
     const std::string file = luaL_checkstring(L, -1);
     const std::string path = ghoul::filesystem::File(file).directoryName();
+
+    lua_settop(L, 0);
     lua_pushstring(L, path.c_str());
     return 1;
 }

src/scripting/scriptscheduler_lua.inl

@@ -39,6 +39,7 @@ int loadFile(lua_State* L) {
         ghoul::lua::loadDictionaryFromFile(missionFileName, L)
     );
 
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -84,6 +85,7 @@ int loadScheduledScript(lua_State* L) {
         return luaL_error(L, "Expected %i-%i arguments, got %i", 2, 4, nArguments);
     }
 
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -95,6 +97,7 @@ int clear(lua_State* L) {
 
     OsEng.scriptScheduler().clearSchedule();
 
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 

src/util/spicemanager_lua.inl

@@ -49,7 +49,10 @@ int loadKernel(lua_State* L) {
     }
     unsigned int result = SpiceManager::ref().loadKernel(argument);
 
+    lua_settop(L, 0);
     lua_pushnumber(L, result);
+
+    ghoul_assert(lua_gettop(L) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 
@@ -71,6 +74,8 @@ int unloadKernel(lua_State* L) {
             ghoul::lua::errorLocation(L) <<
             "Expected argument of type 'string' or 'number'"
         );
+        lua_settop(L, 0);
+        ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
         return 0;
     }
 
@@ -84,6 +89,9 @@ int unloadKernel(lua_State* L) {
         SpiceManager::ref().unloadKernel(argument);
     }
 
+    lua_settop(L, 0);
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 

src/util/time_lua.inl

@@ -46,6 +46,7 @@ int time_setDeltaTime(lua_State* L) {
     if (isNumber) {
         double value = lua_tonumber(L, -1);
         OsEng.timeManager().time().setDeltaTime(value);
+        ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
         return 0;
     }
     else {
@@ -67,6 +68,7 @@ int time_setDeltaTime(lua_State* L) {
  */
 int time_deltaTime(lua_State* L) {
     lua_pushnumber(L, OsEng.timeManager().time().deltaTime());
+    ghoul_assert(lua_gettop(L) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 
@@ -82,6 +84,7 @@ int time_togglePause(lua_State* L) {
     }
 
     OsEng.timeManager().time().togglePause();
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -98,6 +101,8 @@ int time_setPause(lua_State* L) {
 
     bool pause = lua_toboolean(L, -1) == 1;
     OsEng.timeManager().time().setPause(pause);
+
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -137,6 +142,7 @@ int time_setTime(lua_State* L) {
         OsEng.timeManager().time().setTime(time);
         return 0;
     }
+    ghoul_assert(lua_gettop(L) == 0, "Incorrect number of items left on stack");
     return 0;
 }
 
@@ -148,6 +154,7 @@ int time_setTime(lua_State* L) {
  */
 int time_currentTime(lua_State* L) {
     lua_pushnumber(L, OsEng.timeManager().time().j2000Seconds());
+    ghoul_assert(lua_gettop(L) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 
@@ -159,6 +166,7 @@ int time_currentTime(lua_State* L) {
  */
 int time_currentTimeUTC(lua_State* L) {
     lua_pushstring(L, OsEng.timeManager().time().UTC().c_str());
+    ghoul_assert(lua_gettop(L) == 1, "Incorrect number of items left on stack");
     return 1;
 }
 
@@ -182,6 +190,7 @@ int time_currentWallTime(lua_State* L) {
         utcTime->tm_sec
     );
     lua_pushstring(L, time.c_str());
+    ghoul_assert(lua_gettop(L) == 1, "Incorrect number of items left on stack");
     return 1;
 }