Fix a nasty race condition when trying to unschedule a tickAfterNext

task *before* the task actually makes it to the task queue

(Because that only happens on the next UI frame, in the current frame,
what's in the task queue is the anonymous wrapper function that passes
action to nextTick).

plugins/autosuspend.koplugin/main.lua

@@ -37,6 +37,7 @@ local AutoSuspend = WidgetContainer:new{
     task = nil,
     standby_task = nil,
     leave_standby_task = nil,
+    wrapped_leave_standby_task = nil,
     going_to_suspend = nil,
 }
 
@@ -184,6 +185,7 @@ function AutoSuspend:onCloseWidget()
 
     self:_unschedule_standby()
     self.standby_task = nil
+    self.wrapped_leave_standby_task = nil
     self.leave_standby_task = nil
 end
 
@@ -203,7 +205,13 @@ function AutoSuspend:_unschedule_standby()
     end
 
     -- Make sure we don't trigger a ghost LeaveStandby event...
+    if self.wrapped_leave_standby_task then
+        logger.dbg("AutoSuspend: unschedule leave standby task wrapper")
+        UIManager:unschedule(self.wrapped_leave_standby_task)
+    end
+
     if self.leave_standby_task then
+        logger.dbg("AutoSuspend: unschedule leave standby task")
         UIManager:unschedule(self.leave_standby_task)
     end
 end
@@ -330,6 +338,8 @@ end
 
 function AutoSuspend:onLeaveStandby()
     logger.dbg("AutoSuspend: onLeaveStandby")
+    -- If the Event got through, tickAfterNext did its thing, clear the reference to the initial nextTick wrapper...
+    self.wrapped_leave_standby_task = nil
     -- Unschedule suspend and shutdown, as the realtime clock has ticked
     self:_unschedule()
     -- Reschedule suspend and shutdown (we'll recompute the delay based on the last user input, *not* the current time).
@@ -594,7 +604,7 @@ function AutoSuspend:AllowStandbyHandler()
         -- (in case we were woken up by user input, as opposed to an rtc wake alarm)!
         -- (This ensures we'll use an up to date last_action_time, and that it only ever gets updated from *user* input).
         -- NOTE: UIManager consumes scheduled tasks before input events, which is why we can't use nextTick.
-        UIManager:tickAfterNext(self.leave_standby_task)
+        self.wrapped_leave_standby_task = UIManager:tickAfterNext(self.leave_standby_task)
     end
 end