Fix for bug#28075 COM_DEBUG crashes mysqld

Uninitialized in the constructor member variables were
pointing to nirvana and causing a crash when debug information
of the Event Scheduler was dumped in result to COM_DEBUG
packet sent to the server.

sql/event_queue.cc

@@ -70,10 +70,14 @@ event_queue_element_compare_q(void *vptr, byte* a, byte *b)
 */
 
 Event_queue::Event_queue()
-  :mutex_last_locked_at_line(0), mutex_last_unlocked_at_line(0),
+  :next_activation_at(0),
+   mutex_last_locked_at_line(0),
+   mutex_last_unlocked_at_line(0),
+   mutex_last_locked_in_func("n/a"),
+   mutex_last_unlocked_in_func("n/a"),
+   mutex_last_attempted_lock_in_func("n/a"),
    mutex_last_attempted_lock_at_line(0),
    mutex_queue_data_locked(FALSE),
-   next_activation_at(0),
    mutex_queue_data_attempting_lock(FALSE)
 {
   mutex_last_unlocked_in_func= mutex_last_locked_in_func=
@@ -739,8 +743,11 @@ Event_queue::dump_internal_status()
 
   MYSQL_TIME time;
   my_tz_UTC->gmt_sec_to_TIME(&time, next_activation_at);
-  printf("Next activation : %04d-%02d-%02d %02d:%02d:%02d\n",
-         time.year, time.month, time.day, time.hour, time.minute, time.second);
+  if (time.year != 1970)
+    printf("Next activation : %04d-%02d-%02d %02d:%02d:%02d\n",
+           time.year, time.month, time.day, time.hour, time.minute, time.second);
+  else
+    printf("Next activation : never");
 
   DBUG_VOID_RETURN;
 }

sql/event_queue.h

@@ -104,7 +104,6 @@ private:
   bool mutex_queue_data_locked;
   bool mutex_queue_data_attempting_lock;
   bool waiting_on_cond;
-
 };
 
 #endif /* _EVENT_QUEUE_H_ */

sql/event_scheduler.cc

@@ -42,7 +42,6 @@ Event_db_repository *Event_worker_thread::db_repository;
 static
 const LEX_STRING scheduler_states_names[] =
 {
-  { C_STRING_WITH_LEN("UNINITIALIZED") },
   { C_STRING_WITH_LEN("INITIALIZED") },
   { C_STRING_WITH_LEN("RUNNING") },
   { C_STRING_WITH_LEN("STOPPING") }
@@ -331,9 +330,15 @@ end:
 
 
 Event_scheduler::Event_scheduler(Event_queue *queue_arg)
-  :state(UNINITIALIZED),
+  :state(INITIALIZED),
   scheduler_thd(NULL),
   queue(queue_arg),
+  mutex_last_locked_at_line(0),
+  mutex_last_unlocked_at_line(0),
+  mutex_last_locked_in_func("n/a"),
+  mutex_last_unlocked_in_func("n/a"),
+  mutex_scheduler_data_locked(FALSE),
+  waiting_on_cond(FALSE),
   started_events(0)
 {
   pthread_mutex_init(&LOCK_scheduler_state, MY_MUTEX_INIT_FAST);

sql/event_scheduler.h

@@ -111,8 +111,7 @@ private:
 
   enum enum_state
   {
-    UNINITIALIZED = 0,
-    INITIALIZED,
+    INITIALIZED = 0,
     RUNNING,
     STOPPING
   };