Fix actor bug arising from overwriting task specifications in the local scheduler (#513)

* copy task specifications put into the actor task cache so it won't get overwritten when the scheduler receives the next task

* cleanup

* cleanup and fix

* linting

* fix jenkins test

* fix linting

src/common/lib/python/common_extension.cc

@@ -99,8 +99,7 @@ PyObject *PyTask_from_string(PyObject *self, PyObject *args) {
   PyTask *result = PyObject_New(PyTask, &PyTaskType);
   result = (PyTask *) PyObject_Init((PyObject *) result, &PyTaskType);
   result->size = size;
-  result->spec = (TaskSpec *) malloc(size);
-  memcpy(result->spec, data, size);
+  result->spec = TaskSpec_copy((TaskSpec *) data, size);
   /* TODO(pcm): Use flatbuffers validation here. */
   return (PyObject *) result;
 }

src/common/task.cc

@@ -288,6 +288,12 @@ bool TaskSpec_is_dependent_on(TaskSpec *spec, ObjectID object_id) {
   return false;
 }
 
+TaskSpec *TaskSpec_copy(TaskSpec *spec, int64_t task_spec_size) {
+  TaskSpec *copy = (TaskSpec *) malloc(task_spec_size);
+  memcpy(copy, spec, task_spec_size);
+  return copy;
+}
+
 void TaskSpec_free(TaskSpec *spec) {
   free(spec);
 }

src/common/task.h

@@ -291,6 +291,15 @@ ObjectID task_compute_put_id(TaskID task_id, int64_t put_index);
  */
 void TaskSpec_print(TaskSpec *spec, UT_string *output);
 
+/**
+ * Create a copy of the task spec. Must be freed with TaskSpec_free after use.
+ *
+ * @param spec The task specification that will be copied.
+ * @param task_spec_size The size of the task specification in bytes.
+ * @returns Pointer to the copy of the task specification.
+ */
+TaskSpec *TaskSpec_copy(TaskSpec *spec, int64_t task_spec_size);
+
 /**
  * Free a task_spec.
  *
@@ -355,7 +364,7 @@ Task *Task_alloc(TaskSpec *spec,
                  DBClientID local_scheduler_id);
 
 /**
- * Create a copy of the task. Must be freed with free_task after use.
+ * Create a copy of the task. Must be freed with Task_free after use.
  *
  * @param other The task that will be copied.
  * @returns Pointer to the copy of the task.