Event exec timer fix for #2889 (#2890)

Signed-off-by: Janosch Machowinski <[email protected]>
Signed-off-by: Janosch Machowinski <[email protected]>
Co-authored-by: Janosch Machowinski <[email protected]>
Co-authored-by: Alejandro Hernández Cordero <[email protected]>

Author: 3 people

rclcpp/src/rclcpp/experimental/timers_manager.cpp

@@ -273,20 +273,22 @@ void TimersManager::run_timers()
     if (!time_to_sleep.has_value() || (time_to_sleep.value() == std::chrono::nanoseconds::max()) ) {
       // Wait until notification that timers have been updated
       timers_cv_.wait(lock, [this]() {return timers_updated_;});
+    } else if (time_to_sleep.value() != std::chrono::nanoseconds::zero()) {
+      // If time_to_sleep is zero, we immediately execute. Otherwise, wait
+      // until timeout or notification that timers have been updated
+      timers_cv_.wait_for(lock, time_to_sleep.value(), [this]() {return timers_updated_;});
+    }
 
+    if (timers_updated_) {
       // Re-heap in case ordering changed due to a cancelled timer
       // re-activating.
       TimersHeap locked_heap = weak_timers_heap_.validate_and_lock();
       locked_heap.heapify();
       weak_timers_heap_.store(locked_heap);
-    } else if (time_to_sleep.value() != std::chrono::nanoseconds::zero()) {
-      // If time_to_sleep is zero, we immediately execute. Otherwise, wait
-      // until timeout or notification that timers have been updated
-      timers_cv_.wait_for(lock, time_to_sleep.value(), [this]() {return timers_updated_;});
-    }
 
-    // Reset timers updated flag
-    timers_updated_ = false;
+      // Reset timers updated flag
+      timers_updated_ = false;
+    }
 
     // Execute timers
     this->execute_ready_timers_unsafe();