Pass a errfunc to lua_pcall to get a traceback

src/script/common/c_content.cpp

@@ -871,6 +871,8 @@ void read_groups(lua_State *L, int index,
 /******************************************************************************/
 void push_items(lua_State *L, const std::vector<ItemStack> &items)
 {
+	lua_pushcfunction(L, script_error_handler);
+	int errorhandler = lua_gettop(L);
 	// Get the table insert function
 	lua_getglobal(L, "table");
 	lua_getfield(L, -1, "insert");
@@ -883,11 +885,12 @@ void push_items(lua_State *L, const std::vector<ItemStack> &items)
 		lua_pushvalue(L, table_insert);
 		lua_pushvalue(L, table);
 		LuaItemStack::create(L, item);
-		if(lua_pcall(L, 2, 0, 0))
-			script_error(L, "error: %s", lua_tostring(L, -1));
+		if(lua_pcall(L, 2, 0, errorhandler))
+			script_error(L);
 	}
-	lua_remove(L, -2); // Remove table
 	lua_remove(L, -2); // Remove insert
+	lua_remove(L, -2); // Remove table
+	lua_remove(L, -2); // Remove error handler
 }
 
 /******************************************************************************/

src/script/common/c_internal.cpp

@@ -23,32 +23,41 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 std::string script_get_backtrace(lua_State *L)
 {
 	std::string s;
-	lua_getfield(L, LUA_GLOBALSINDEX, "debug");
+	lua_getglobal(L, "debug");
 	if(lua_istable(L, -1)){
 		lua_getfield(L, -1, "traceback");
-		if(lua_isfunction(L, -1)){
+		if(lua_isfunction(L, -1)) {
 			lua_call(L, 0, 1);
 			if(lua_isstring(L, -1)){
-				s += lua_tostring(L, -1);
+				s = lua_tostring(L, -1);
 			}
-			lua_pop(L, 1);
-		}
-		else{
-			lua_pop(L, 1);
 		}
+		lua_pop(L, 1);
 	}
 	lua_pop(L, 1);
 	return s;
 }
 
-void script_error(lua_State *L, const char *fmt, ...)
+int script_error_handler(lua_State *L) {
+	lua_getglobal(L, "debug");
+	if (!lua_istable(L, -1)) {
+		lua_pop(L, 1);
+		return 1;
+	}
+	lua_getfield(L, -1, "traceback");
+	if (!lua_isfunction(L, -1)) {
+		lua_pop(L, 2);
+		return 1;
+	}
+	lua_pushvalue(L, 1);
+	lua_pushinteger(L, 2);
+	lua_call(L, 2, 1);
+	return 1;
+}
+
+void script_error(lua_State *L)
 {
-	va_list argp;
-	va_start(argp, fmt);
-	char buf[10000];
-	vsnprintf(buf, 10000, fmt, argp);
-	va_end(argp);
-	throw LuaError(L, buf);
+	throw LuaError(NULL, lua_tostring(L, -1));
 }
 
 // Push the list of callbacks (a lua table).
@@ -61,13 +70,20 @@ void script_run_callbacks(lua_State *L, int nargs, RunCallbacksMode mode)
 {
 	// Insert the return value into the lua stack, below the table
 	assert(lua_gettop(L) >= nargs + 1);
+
 	lua_pushnil(L);
-	lua_insert(L, -(nargs + 1) - 1);
+	int rv = lua_gettop(L) - nargs - 1;
+	lua_insert(L, rv);
+
+	// Insert error handler after return value
+	lua_pushcfunction(L, script_error_handler);
+	int errorhandler = rv + 1;
+	lua_insert(L, errorhandler);
+
 	// Stack now looks like this:
-	// ... <return value = nil> <table> <arg#1> <arg#2> ... <arg#n>
+	// ... <return value = nil> <error handler> <table> <arg#1> <arg#2> ... <arg#n>
 
-	int rv = lua_gettop(L) - nargs - 1;
-	int table = rv + 1;
+	int table = errorhandler + 1;
 	int arg = table + 1;
 
 	luaL_checktype(L, table, LUA_TTABLE);
@@ -81,8 +97,8 @@ void script_run_callbacks(lua_State *L, int nargs, RunCallbacksMode mode)
 		// Call function
 		for(int i = 0; i < nargs; i++)
 			lua_pushvalue(L, arg+i);
-		if(lua_pcall(L, nargs, 1, 0))
-			script_error(L, "error: %s", lua_tostring(L, -1));
+		if(lua_pcall(L, nargs, 1, errorhandler))
+			script_error(L);
 
 		// Move return value to designated space in stack
 		// Or pop it

src/script/common/c_internal.h

@@ -64,9 +64,10 @@ enum RunCallbacksMode
 	// are converted by lua_toboolean to true or false, respectively.
 };
 
-std::string script_get_backtrace   (lua_State *L);
-void        script_error           (lua_State *L, const char *fmt, ...);
-void        script_run_callbacks   (lua_State *L, int nargs,
-                                    RunCallbacksMode mode);
+std::string script_get_backtrace(lua_State *L);
+int script_error_handler(lua_State *L);
+void script_error(lua_State *L);
+void script_run_callbacks(lua_State *L, int nargs,
+		RunCallbacksMode mode);
 
 #endif /* C_INTERNAL_H_ */

src/script/common/c_types.cpp

@@ -25,9 +25,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 LuaError::LuaError(lua_State *L, const std::string &s)
 {
-	m_s = "LuaError: ";
-	m_s += s + "\n";
-	m_s += script_get_backtrace(L);
+	m_s = "LuaError: " + s;
+	if (L) m_s += '\n' + script_get_backtrace(L);
 }
 
 struct EnumString es_ItemType[] =

src/script/cpp_api/s_base.cpp

@@ -55,23 +55,6 @@ class ModNameStorer
 	}
 };
 
-static int loadScript_ErrorHandler(lua_State *L) {
-	lua_getfield(L, LUA_GLOBALSINDEX, "debug");
-	if (!lua_istable(L, -1)) {
-		lua_pop(L, 1);
-		return 1;
-	}
-	lua_getfield(L, -1, "traceback");
-	if (!lua_isfunction(L, -1)) {
-		lua_pop(L, 2);
-		return 1;
-	}
-	lua_pushvalue(L, 1);
-	lua_pushinteger(L, 2);
-	lua_call(L, 2, 1);
-	return 1;
-}
-
 
 /*
 	ScriptApiBase
@@ -133,7 +116,7 @@ bool ScriptApiBase::loadScript(const std::string &scriptpath)
 
 	lua_State *L = getStack();
 
-	lua_pushcfunction(L, loadScript_ErrorHandler);
+	lua_pushcfunction(L, script_error_handler);
 	int errorhandler = lua_gettop(L);
 
 	int ret = luaL_loadfile(L, scriptpath.c_str()) || lua_pcall(L, 0, 0, errorhandler);
@@ -144,7 +127,7 @@ bool ScriptApiBase::loadScript(const std::string &scriptpath)
 		errorstream<<std::endl;
 		errorstream<<lua_tostring(L, -1)<<std::endl;
 		errorstream<<std::endl;
-		errorstream<<"=======END OF ERROR FROM LUA ========"<<std::endl;
+		errorstream<<"======= END OF ERROR FROM LUA ========"<<std::endl;
 		lua_pop(L, 1); // Pop error message from stack
 		lua_pop(L, 1); // Pop the error handler from stack
 		return false;
@@ -159,19 +142,13 @@ void ScriptApiBase::realityCheck()
 	if(top >= 30){
 		dstream<<"Stack is over 30:"<<std::endl;
 		stackDump(dstream);
-		scriptError("Stack is over 30 (reality check)");
+		throw LuaError(m_luastack, "Stack is over 30 (reality check)");
 	}
 }
 
-void ScriptApiBase::scriptError(const char *fmt, ...)
+void ScriptApiBase::scriptError()
 {
-	va_list argp;
-	va_start(argp, fmt);
-	char buf[10000];
-	vsnprintf(buf, 10000, fmt, argp);
-	va_end(argp);
-	//errorstream<<"SCRIPT ERROR: "<<buf;
-	throw LuaError(m_luastack, buf);
+	throw LuaError(NULL, lua_tostring(m_luastack, -1));
 }
 
 void ScriptApiBase::stackDump(std::ostream &o)

src/script/cpp_api/s_base.h

@@ -31,6 +31,7 @@ extern "C" {
 #include "jthread/jmutex.h"
 #include "jthread/jmutexautolock.h"
 #include "common/c_types.h"
+#include "common/c_internal.h"
 
 #define SCRIPTAPI_LOCK_DEBUG
 
@@ -65,7 +66,7 @@ class ScriptApiBase {
 		{ return m_luastack; }
 
 	void realityCheck();
-	void scriptError(const char *fmt, ...);
+	void scriptError();
 	void stackDump(std::ostream &o);
 
 	Server* getServer() { return m_server; }

src/script/cpp_api/s_entity.cpp

@@ -78,25 +78,29 @@ void ScriptApiEntity::luaentity_Activate(u16 id,
 {
 	SCRIPTAPI_PRECHECKHEADER
 
+	lua_pushcfunction(L, script_error_handler);
+	int errorhandler = lua_gettop(L);
+
 	verbosestream<<"scriptapi_luaentity_activate: id="<<id<<std::endl;
 
 	// Get minetest.luaentities[id]
-	luaentity_get(L,id);
+	luaentity_get(L, id);
 	int object = lua_gettop(L);
 
 	// Get on_activate function
-	lua_pushvalue(L, object);
 	lua_getfield(L, -1, "on_activate");
-	if(!lua_isnil(L, -1)){
+	if(!lua_isnil(L, -1)) {
 		luaL_checktype(L, -1, LUA_TFUNCTION);
 		lua_pushvalue(L, object); // self
 		lua_pushlstring(L, staticdata.c_str(), staticdata.size());
 		lua_pushinteger(L, dtime_s);
 		// Call with 3 arguments, 0 results
-		if(lua_pcall(L, 3, 0, 0))
-			scriptError("error running function on_activate: %s\n",
-					lua_tostring(L, -1));
+		if(lua_pcall(L, 3, 0, errorhandler))
+			scriptError();
+	} else {
+		lua_pop(L, 1);
 	}
+	lua_pop(L, 2); // Pop object and error handler
 }
 
 void ScriptApiEntity::luaentity_Remove(u16 id)
@@ -123,26 +127,29 @@ std::string ScriptApiEntity::luaentity_GetStaticdata(u16 id)
 {
 	SCRIPTAPI_PRECHECKHEADER
 
+	lua_pushcfunction(L, script_error_handler);
+	int errorhandler = lua_gettop(L);
+
 	//infostream<<"scriptapi_luaentity_get_staticdata: id="<<id<<std::endl;
 
 	// Get minetest.luaentities[id]
-	luaentity_get(L,id);
+	luaentity_get(L, id);
 	int object = lua_gettop(L);
 
 	// Get get_staticdata function
-	lua_pushvalue(L, object);
 	lua_getfield(L, -1, "get_staticdata");
 	if(lua_isnil(L, -1))
 		return "";
 
 	luaL_checktype(L, -1, LUA_TFUNCTION);
 	lua_pushvalue(L, object); // self
 	// Call with 1 arguments, 1 results
-	if(lua_pcall(L, 1, 1, 0))
-		scriptError("error running function get_staticdata: %s\n",
-				lua_tostring(L, -1));
+	if(lua_pcall(L, 1, 1, errorhandler))
+		scriptError();
+	lua_remove(L, object); // Remove object
+	lua_remove(L, errorhandler); // Remove error handler
 
-	size_t len=0;
+	size_t len = 0;
 	const char *s = lua_tolstring(L, -1, &len);
 	return std::string(s, len);
 }
@@ -192,10 +199,13 @@ void ScriptApiEntity::luaentity_Step(u16 id, float dtime)
 {
 	SCRIPTAPI_PRECHECKHEADER
 
+	lua_pushcfunction(L, script_error_handler);
+	int errorhandler = lua_gettop(L);
+
 	//infostream<<"scriptapi_luaentity_step: id="<<id<<std::endl;
 
 	// Get minetest.luaentities[id]
-	luaentity_get(L,id);
+	luaentity_get(L, id);
 	int object = lua_gettop(L);
 	// State: object is at top of stack
 	// Get step function
@@ -206,8 +216,10 @@ void ScriptApiEntity::luaentity_Step(u16 id, float dtime)
 	lua_pushvalue(L, object); // self
 	lua_pushnumber(L, dtime); // dtime
 	// Call with 2 arguments, 0 results
-	if(lua_pcall(L, 2, 0, 0))
-		scriptError("error running function 'on_step': %s\n", lua_tostring(L, -1));
+	if(lua_pcall(L, 2, 0, errorhandler))
+		scriptError();
+	lua_remove(L, object); // Remove object
+	lua_remove(L, errorhandler); // Remove error handler
 }
 
 // Calls entity:on_punch(ObjectRef puncher, time_from_last_punch,
@@ -218,6 +230,9 @@ void ScriptApiEntity::luaentity_Punch(u16 id,
 {
 	SCRIPTAPI_PRECHECKHEADER
 
+	lua_pushcfunction(L, script_error_handler);
+	int errorhandler = lua_gettop(L);
+
 	//infostream<<"scriptapi_luaentity_step: id="<<id<<std::endl;
 
 	// Get minetest.luaentities[id]
@@ -235,8 +250,10 @@ void ScriptApiEntity::luaentity_Punch(u16 id,
 	push_tool_capabilities(L, *toolcap);
 	push_v3f(L, dir);
 	// Call with 5 arguments, 0 results
-	if(lua_pcall(L, 5, 0, 0))
-		scriptError("error running function 'on_punch': %s\n", lua_tostring(L, -1));
+	if(lua_pcall(L, 5, 0, errorhandler))
+		scriptError();
+	lua_remove(L, object); // Remove object
+	lua_remove(L, errorhandler); // Remove error handler
 }
 
 // Calls entity:on_rightclick(ObjectRef clicker)
@@ -245,6 +262,9 @@ void ScriptApiEntity::luaentity_Rightclick(u16 id,
 {
 	SCRIPTAPI_PRECHECKHEADER
 
+	lua_pushcfunction(L, script_error_handler);
+	int errorhandler = lua_gettop(L);
+
 	//infostream<<"scriptapi_luaentity_step: id="<<id<<std::endl;
 
 	// Get minetest.luaentities[id]
@@ -259,7 +279,9 @@ void ScriptApiEntity::luaentity_Rightclick(u16 id,
 	lua_pushvalue(L, object); // self
 	objectrefGetOrCreate(clicker); // Clicker reference
 	// Call with 2 arguments, 0 results
-	if(lua_pcall(L, 2, 0, 0))
-		scriptError("error running function 'on_rightclick': %s\n", lua_tostring(L, -1));
+	if(lua_pcall(L, 2, 0, errorhandler))
+		scriptError();
+	lua_remove(L, object); // Remove object
+	lua_remove(L, errorhandler); // Remove error handler
 }