[ScriptExecutor] Error Handler is not removed properly from stack in script executor.
Bug: 269522410
Test: atest ScriptExecutorFunctionalTests:ScriptExecutorFunctionalTest
Change-Id: I6f6a80b9baacf6a6281d5fe4290d2c75f6ab9495
diff --git a/packages/ScriptExecutor/src/LuaEngine.cpp b/packages/ScriptExecutor/src/LuaEngine.cpp
index 64b74d2..a450f84 100644
--- a/packages/ScriptExecutor/src/LuaEngine.cpp
+++ b/packages/ScriptExecutor/src/LuaEngine.cpp
@@ -147,6 +147,13 @@
int err_handler_index = -n_args - 2;
lua_insert(mLuaState, err_handler_index);
+ // After lua_pcall, the function and all arguments are removed from the stack i.e. (n_args+1)
+ // If there is no error then lua_pcall pushes "n_results" elements to the stack.
+ // But in case of error, lua_pcall pushes exactly one element (error message).
+ // So, "error message" will be at top of the stack i.e. "-1".
+ // Therefore, we need to pop error_handler explicitly.
+ // error_handler will be at "-2" index from top of stack after lua_pcall,
+ // but once we pop error_message from top of stack, error_handler's new index will be "-1".
int status = lua_pcall(mLuaState, n_args, n_results, err_handler_index);
if (status) {
const char* error = lua_tostring(mLuaState, -1);
@@ -162,8 +169,7 @@
std::string error_msg = s.substr(0, dpos - 1);
std::string stack_traceback = s.substr(dpos + delimiter.length() + 2);
- lua_remove(mLuaState, err_handler_index); // remove the error_handler from the stack.
- lua_pop(mLuaState, 1); // pop the error object from the stack.
+ lua_pop(mLuaState, 2); // pop top 2 elements (error message & error handler) from the stack
std::ostringstream out;
out << "Error encountered while running the script. The returned error code=" << status
<< ". Refer to lua.h file of Lua C API library for error code definitions. Error: "
@@ -171,6 +177,7 @@
sListener->onError(ERROR_TYPE_LUA_RUNTIME_ERROR, out.str().c_str(),
stack_traceback.c_str());
}
+ lua_pop(mLuaState, 1); // pop top element (error handler) from the stack.
return status;
}
