From 1c9eb0b36798cc202bc584cae5c0bce78d2ca307 Mon Sep 17 00:00:00 2001
From: William Woodall <william@osrfoundation.org>
Date: Tue, 17 Nov 2015 11:32:58 -0800
Subject: [PATCH] only set scope exit after it was determined that spinning was
 changed to true

---
 rclcpp/src/rclcpp/executor.cpp                           | 4 ++--
 rclcpp/src/rclcpp/executors/multi_threaded_executor.cpp  | 2 +-
 rclcpp/src/rclcpp/executors/single_threaded_executor.cpp | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/rclcpp/src/rclcpp/executor.cpp b/rclcpp/src/rclcpp/executor.cpp
index 5e0f290..981934c 100644
--- a/rclcpp/src/rclcpp/executor.cpp
+++ b/rclcpp/src/rclcpp/executor.cpp
@@ -110,10 +110,10 @@ Executor::spin_node_some(rclcpp::node::Node::SharedPtr node)
 void
 Executor::spin_some()
 {
-  RCLCPP_SCOPE_EXIT(this->spinning.store(false); );
   if (spinning.exchange(true)) {
     throw std::runtime_error("spin_some() called while already spinning");
   }
+  RCLCPP_SCOPE_EXIT(this->spinning.store(false); );
   AnyExecutable::SharedPtr any_exec;
   while ((any_exec = get_next_executable(std::chrono::milliseconds::zero())) && spinning.load()) {
     execute_any_executable(any_exec);
@@ -123,10 +123,10 @@ Executor::spin_some()
 void
 Executor::spin_once(std::chrono::nanoseconds timeout)
 {
-  RCLCPP_SCOPE_EXIT(this->spinning.store(false); );
   if (spinning.exchange(true)) {
     throw std::runtime_error("spin_once() called while already spinning");
   }
+  RCLCPP_SCOPE_EXIT(this->spinning.store(false); );
   auto any_exec = get_next_executable(timeout);
   if (any_exec) {
     execute_any_executable(any_exec);
diff --git a/rclcpp/src/rclcpp/executors/multi_threaded_executor.cpp b/rclcpp/src/rclcpp/executors/multi_threaded_executor.cpp
index e7bcc63..63d555f 100644
--- a/rclcpp/src/rclcpp/executors/multi_threaded_executor.cpp
+++ b/rclcpp/src/rclcpp/executors/multi_threaded_executor.cpp
@@ -38,10 +38,10 @@ MultiThreadedExecutor::~MultiThreadedExecutor() {}
 void
 MultiThreadedExecutor::spin()
 {
-  RCLCPP_SCOPE_EXIT(this->spinning.store(false); );
   if (spinning.exchange(true)) {
     throw std::runtime_error("spin() called while already spinning");
   }
+  RCLCPP_SCOPE_EXIT(this->spinning.store(false); );
   std::vector<std::thread> threads;
   {
     std::lock_guard<std::mutex> wait_lock(wait_mutex_);
diff --git a/rclcpp/src/rclcpp/executors/single_threaded_executor.cpp b/rclcpp/src/rclcpp/executors/single_threaded_executor.cpp
index 87c25bd..204d422 100644
--- a/rclcpp/src/rclcpp/executors/single_threaded_executor.cpp
+++ b/rclcpp/src/rclcpp/executors/single_threaded_executor.cpp
@@ -28,10 +28,10 @@ SingleThreadedExecutor::~SingleThreadedExecutor() {}
 void
 SingleThreadedExecutor::spin()
 {
-  RCLCPP_SCOPE_EXIT(this->spinning.store(false); );
   if (spinning.exchange(true)) {
     throw std::runtime_error("spin_some() called while already spinning");
   }
+  RCLCPP_SCOPE_EXIT(this->spinning.store(false); );
   while (rclcpp::utilities::ok() && spinning.load()) {
     auto any_exec = get_next_executable();
     execute_any_executable(any_exec);