Load CSM environment after the restrictions are known

Safety-guards for CSM callbacks to abort on a bad implementation
Only run callbacks when the mods are loaded (and with it: builtin)

Duplication checks inside constructors

10 files changed, 64 insertions, 55 deletions

diff --git a/src/client/camera.cpp b/src/client/camera.cpp
index 7e953d4c7..025bd081d 100644
--- a/src/client/camera.cpp
+++ b/src/client/camera.cpp
@@ -99,9 +99,9 @@ bool Camera::successfullyCreated(std::string &error_message)
 		error_message.clear();
 	}
 
-	if (g_settings->getBool("enable_client_modding")) {
+	if (m_client->modsLoaded())
 		m_client->getScript()->on_camera_ready(this);
-	}
+
 	return error_message.empty();
 }
 
diff --git a/src/client/client.cpp b/src/client/client.cpp
index 4c5485325..9535acc8e 100644
--- a/src/client/client.cpp
+++ b/src/client/client.cpp
@@ -108,15 +108,6 @@ Client::Client(
 		m_minimap = new Minimap(this);
 	}
 	m_cache_save_interval = g_settings->getU16("server_map_save_interval");
-
-	m_modding_enabled = g_settings->getBool("enable_client_modding");
-	// Only create the client script environment if client scripting is enabled by the
-	// client.
-	if (m_modding_enabled) {
-		m_script = new ClientScripting(this);
-		m_env.setScript(m_script);
-		m_script->setEnv(&m_env);
-	}
 }
 
 void Client::loadMods()
@@ -124,9 +115,8 @@ void Client::loadMods()
 	// Don't load mods twice.
 	// If client scripting is disabled by the client, don't load builtin or
 	// client-provided mods.
-	if (m_mods_loaded || !m_modding_enabled) {
+	if (m_mods_loaded || !g_settings->getBool("enable_client_modding"))
 		return;
-	}
 
 	// If client scripting is disabled by the server, don't load builtin or
 	// client-provided mods.
@@ -135,11 +125,13 @@ void Client::loadMods()
 	if (checkCSMRestrictionFlag(CSMRestrictionFlags::CSM_RF_LOAD_CLIENT_MODS)) {
 		warningstream << "Client-provided mod loading is disabled by server." <<
 			std::endl;
-		// This line is needed because builtin is not loaded
-		m_modding_enabled = false;
 		return;
 	}
 
+	m_script = new ClientScripting(this);
+	m_env.setScript(m_script);
+	m_script->setEnv(&m_env);
+
 	// Load builtin
 	scanModIntoMemory(BUILTIN_MOD_NAME, getBuiltinLuaPath());
 	m_script->loadModFromMemory(BUILTIN_MOD_NAME);
@@ -185,9 +177,15 @@ void Client::loadMods()
 	for (const ModSpec &mod : m_mods)
 		m_script->loadModFromMemory(mod.name);
 
+	// Mods are done loading. Unlock callbacks
+	m_mods_loaded = true;
+
 	// Run a callback when mods are loaded
 	m_script->on_mods_loaded();
-	m_mods_loaded = true;
+	if (m_state == LC_Ready)
+		m_script->on_client_ready(m_env.getLocalPlayer());
+	if (m_camera)
+		m_script->on_camera_ready(m_camera);
 }
 
 bool Client::checkBuiltinIntegrity()
@@ -239,7 +237,7 @@ const ModSpec* Client::getModSpec(const std::string &modname) const
 void Client::Stop()
 {
 	m_shutdown = true;
-	if (m_modding_enabled)
+	if (m_mods_loaded)
 		m_script->on_shutdown();
 	//request all client managed threads to stop
 	m_mesh_update_thread.stop();
@@ -249,7 +247,7 @@ void Client::Stop()
 		m_localdb->endSave();
 	}
 
-	if (m_modding_enabled)
+	if (m_mods_loaded)
 		delete m_script;
 }
 
@@ -1497,7 +1495,7 @@ void Client::typeChatMessage(const std::wstring &message)
 		return;
 
 	// If message was consumed by script API, don't send it to server
-	if (m_modding_enabled && m_script->on_sending_message(wide_to_utf8(message)))
+	if (m_mods_loaded && m_script->on_sending_message(wide_to_utf8(message)))
 		return;
 
 	// Send to others
@@ -1693,9 +1691,8 @@ void Client::afterContentReceived()
 	m_state = LC_Ready;
 	sendReady();
 
-	if (g_settings->getBool("enable_client_modding")) {
+	if (m_mods_loaded)
 		m_script->on_client_ready(m_env.getLocalPlayer());
-	}
 
 	text = wgettext("Done!");
 	RenderingEngine::draw_load_screen(text, guienv, m_tsrc, 0, 100);
diff --git a/src/client/client.h b/src/client/client.h
index 85456fe4d..6dad48c3d 100644
--- a/src/client/client.h
+++ b/src/client/client.h
@@ -397,7 +397,6 @@ public:
 	}
 
 	ClientScripting *getScript() { return m_script; }
-	const bool moddingEnabled() const { return m_modding_enabled; }
 	const bool modsLoaded() const { return m_mods_loaded; }
 
 	void pushToEventQueue(ClientEvent *event);
diff --git a/src/client/game.cpp b/src/client/game.cpp
index 5bf41bcd6..b5508f2cb 100644
--- a/src/client/game.cpp
+++ b/src/client/game.cpp
@@ -184,7 +184,7 @@ struct LocalFormspecHandler : public TextDest
 			return;
 		}
 
-		if (m_client && m_client->moddingEnabled())
+		if (m_client && m_client->modsLoaded())
 			m_client->getScript()->on_formspec_input(m_formname, fields);
 	}
 
@@ -1870,7 +1870,7 @@ void Game::processKeyInput()
 	} else if (wasKeyDown(KeyType::CMD)) {
 		openConsole(0.2, L"/");
 	} else if (wasKeyDown(KeyType::CMD_LOCAL)) {
-		if (client->moddingEnabled())
+		if (client->modsLoaded())
 			openConsole(0.2, L".");
 		else
 			m_game_ui->showStatusText(wgettext("Client side scripting is disabled"));
@@ -2026,7 +2026,7 @@ void Game::openInventory()
 	InventoryLocation inventoryloc;
 	inventoryloc.setCurrentPlayer();
 
-	if (!client->moddingEnabled()
+	if (!client->modsLoaded()
 			|| !client->getScript()->on_inventory_open(fs_src->m_client->getInventory(inventoryloc))) {
 		TextDest *txt_dst = new TextDestPlayerInventory(client);
 		auto *&formspec = m_game_ui->updateFormspec("");
@@ -2516,9 +2516,8 @@ void Game::handleClientEvent_None(ClientEvent *event, CameraOrientation *cam)
 
 void Game::handleClientEvent_PlayerDamage(ClientEvent *event, CameraOrientation *cam)
 {
-	if (client->moddingEnabled()) {
+	if (client->modsLoaded())
 		client->getScript()->on_damage_taken(event->player_damage.amount);
-	}
 
 	// Damage flash and hurt tilt are not used at death
 	if (client->getHP() > 0) {
@@ -2546,7 +2545,7 @@ void Game::handleClientEvent_Deathscreen(ClientEvent *event, CameraOrientation *
 {
 	// If client scripting is enabled, deathscreen is handled by CSM code in
 	// builtin/client/init.lua
-	if (client->moddingEnabled())
+	if (client->modsLoaded())
 		client->getScript()->on_death();
 	else
 		showDeathFormspec();
@@ -3033,9 +3032,8 @@ void Game::processPlayerInteraction(f32 dtime, bool show_hud, bool show_debug)
 	else
 		runData.repeat_rightclick_timer = 0;
 
-
 	if (selected_def.usable && input->getLeftState()) {
-		if (input->getLeftClicked() && (!client->moddingEnabled()
+		if (input->getLeftClicked() && (!client->modsLoaded()
 				|| !client->getScript()->on_item_use(selected_item, pointed)))
 			client->interact(INTERACT_USE, pointed);
 	} else if (pointed.type == POINTEDTHING_NODE) {
@@ -3240,7 +3238,7 @@ void Game::handlePointingAtNode(const PointedThing &pointed,
 				soundmaker->m_player_rightpunch_sound =
 						def.sound_place;
 
-				if (client->moddingEnabled())
+				if (client->modsLoaded())
 					client->getScript()->on_placenode(pointed, def);
 			} else {
 				soundmaker->m_player_rightpunch_sound =
@@ -3496,7 +3494,7 @@ void Game::handleDigging(const PointedThing &pointed, const v3s16 &nodepos,
 	if (!runData.digging) {
 		infostream << "Started digging" << std::endl;
 		runData.dig_instantly = runData.dig_time_complete == 0;
-		if (client->moddingEnabled() && client->getScript()->on_punchnode(nodepos, n))
+		if (client->modsLoaded() && client->getScript()->on_punchnode(nodepos, n))
 			return;
 		client->interact(INTERACT_START_DIGGING, pointed);
 		runData.digging = true;
@@ -3556,7 +3554,7 @@ void Game::handleDigging(const PointedThing &pointed, const v3s16 &nodepos,
 		bool is_valid_position;
 		MapNode wasnode = map.getNode(nodepos, &is_valid_position);
 		if (is_valid_position) {
-			if (client->moddingEnabled() &&
+			if (client->modsLoaded() &&
 					client->getScript()->on_dignode(nodepos, wasnode)) {
 				return;
 			}
diff --git a/src/network/clientpackethandler.cpp b/src/network/clientpackethandler.cpp
index 91829474e..a8ae8a5ef 100644
--- a/src/network/clientpackethandler.cpp
+++ b/src/network/clientpackethandler.cpp
@@ -415,7 +415,7 @@ void Client::handleCommand_ChatMessage(NetworkPacket *pkt)
 	chatMessage->type = (ChatMessageType) message_type;
 
 	// @TODO send this to CSM using ChatMessage object
-	if (moddingEnabled() && m_script->on_receiving_message(
+	if (modsLoaded() && m_script->on_receiving_message(
 			wide_to_utf8(chatMessage->message))) {
 		// Message was consumed by CSM and should not be handled by client
 		delete chatMessage;
@@ -532,9 +532,8 @@ void Client::handleCommand_HP(NetworkPacket* pkt)
 
 	player->hp = hp;
 
-	if (moddingEnabled()) {
+	if (modsLoaded())
 		m_script->on_hp_modification(hp);
-	}
 
 	if (hp < oldhp) {
 		// Add to ClientEvent queue
diff --git a/src/script/cpp_api/s_base.cpp b/src/script/cpp_api/s_base.cpp
index e73f613ce..caa335d76 100644
--- a/src/script/cpp_api/s_base.cpp
+++ b/src/script/cpp_api/s_base.cpp
@@ -232,6 +232,13 @@ void ScriptApiBase::loadModFromMemory(const std::string &mod_name)
 void ScriptApiBase::runCallbacksRaw(int nargs,
 		RunCallbacksMode mode, const char *fxn)
 {
+#ifndef SERVER
+	// Hard fail for bad guarded callbacks
+	// Only run callbacks when the scripting enviroment is loaded
+	FATAL_ERROR_IF(m_type == ScriptingType::Client &&
+			!getClient()->modsLoaded(), fxn);
+#endif
+
 #ifdef SCRIPTAPI_LOCK_DEBUG
 	assert(m_lock_recursion_count > 0);
 #endif
diff --git a/src/script/cpp_api/s_security.cpp b/src/script/cpp_api/s_security.cpp
index 876c7761a..d972be980 100644
--- a/src/script/cpp_api/s_security.cpp
+++ b/src/script/cpp_api/s_security.cpp
@@ -264,6 +264,7 @@ void ScriptApiSecurity::initializeSecurityClient()
 	};
 	static const char *debug_whitelist[] = {
 		"getinfo",
+		"traceback"
 	};
 
 #if USE_LUAJIT
diff --git a/src/script/lua_api/l_camera.cpp b/src/script/lua_api/l_camera.cpp
index 462006777..80071b3b8 100644
--- a/src/script/lua_api/l_camera.cpp
+++ b/src/script/lua_api/l_camera.cpp
@@ -31,19 +31,24 @@ LuaCamera::LuaCamera(Camera *m) : m_camera(m)
 
 void LuaCamera::create(lua_State *L, Camera *m)
 {
+	lua_getglobal(L, "core");
+	luaL_checktype(L, -1, LUA_TTABLE);
+	int objectstable = lua_gettop(L);
+	lua_getfield(L, -1, "camera");
+
+	// Duplication check
+	if (lua_type(L, -1) == LUA_TUSERDATA) {
+		lua_pop(L, 1);
+		return;
+	}
+
 	LuaCamera *o = new LuaCamera(m);
 	*(void **)(lua_newuserdata(L, sizeof(void *))) = o;
 	luaL_getmetatable(L, className);
 	lua_setmetatable(L, -2);
 
-	int camera_object = lua_gettop(L);
-
-	lua_getglobal(L, "core");
-	luaL_checktype(L, -1, LUA_TTABLE);
-	int coretable = lua_gettop(L);
-
-	lua_pushvalue(L, camera_object);
-	lua_setfield(L, coretable, "camera");
+	lua_pushvalue(L, lua_gettop(L));
+	lua_setfield(L, objectstable, "camera");
 }
 
 int LuaCamera::l_set_camera_mode(lua_State *L)
diff --git a/src/script/lua_api/l_localplayer.cpp b/src/script/lua_api/l_localplayer.cpp
index 7444d0e88..3e14e48e4 100644
--- a/src/script/lua_api/l_localplayer.cpp
+++ b/src/script/lua_api/l_localplayer.cpp
@@ -30,20 +30,24 @@ LuaLocalPlayer::LuaLocalPlayer(LocalPlayer *m) : m_localplayer(m)
 
 void LuaLocalPlayer::create(lua_State *L, LocalPlayer *m)
 {
+	lua_getglobal(L, "core");
+	luaL_checktype(L, -1, LUA_TTABLE);
+	int objectstable = lua_gettop(L);
+	lua_getfield(L, -1, "localplayer");
+
+	// Duplication check
+	if (lua_type(L, -1) == LUA_TUSERDATA) {
+		lua_pop(L, 1);
+		return;
+	}
+
 	LuaLocalPlayer *o = new LuaLocalPlayer(m);
 	*(void **)(lua_newuserdata(L, sizeof(void *))) = o;
 	luaL_getmetatable(L, className);
 	lua_setmetatable(L, -2);
 
-	// Keep localplayer object stack id
-	int localplayer_object = lua_gettop(L);
-
-	lua_getglobal(L, "core");
-	luaL_checktype(L, -1, LUA_TTABLE);
-	int coretable = lua_gettop(L);
-
-	lua_pushvalue(L, localplayer_object);
-	lua_setfield(L, coretable, "localplayer");
+	lua_pushvalue(L, lua_gettop(L));
+	lua_setfield(L, objectstable, "localplayer");
 }
 
 int LuaLocalPlayer::l_get_velocity(lua_State *L)
diff --git a/src/script/scripting_client.cpp b/src/script/scripting_client.cpp
index 86e5f2874..239c98e57 100644
--- a/src/script/scripting_client.cpp
+++ b/src/script/scripting_client.cpp
@@ -84,8 +84,7 @@ void ClientScripting::InitializeModApi(lua_State *L, int top)
 
 void ClientScripting::on_client_ready(LocalPlayer *localplayer)
 {
-	lua_State *L = getStack();
-	LuaLocalPlayer::create(L, localplayer);
+	LuaLocalPlayer::create(getStack(), localplayer);
 }
 
 void ClientScripting::on_camera_ready(Camera *camera)