Make rclpy.try_shutdown() behavior to follow rclpy.shutdown() more closely (#868)

Signed-off-by: Ivan Santiago Paunovic <[email protected]>

Author: ivanpauno

rclpy/rclpy/__init__.py

@@ -100,6 +100,13 @@ def get_global_executor() -> 'Executor':
         # imported locally to avoid loading extensions on module import
         from rclpy.executors import SingleThreadedExecutor
         __executor = SingleThreadedExecutor()
+        context = get_default_context()
+
+        def reset_executor():
+            global __executor
+            __executor.shutdown()
+            __executor = None
+        context.on_shutdown(reset_executor)
     return __executor
 
 
@@ -116,10 +123,6 @@ def shutdown(*, context: Context = None, uninstall_handlers: Optional[bool] = No
         If `True`, signal handlers will be uninstalled.
         If not, signal handlers won't be uninstalled.
     """
-    global __executor
-    if __executor is not None:
-        __executor.shutdown()
-        __executor = None
     _shutdown(context=context)
     if (
         uninstall_handlers or (

rclpy/rclpy/context.py

@@ -127,7 +127,7 @@ def on_shutdown(self, callback: Callable[[], None]):
                 if ismethod(callback):
                     self._callbacks.append(weakref.WeakMethod(callback, self._remove_callback))
                 else:
-                    self._callbacks.append(weakref.ref(callback, self._remove_callback))
+                    self._callbacks.append(callback)
 
     def _logging_fini(self):
         # This function must be called with self._lock held.

rclpy/rclpy/utilities.py

@@ -60,9 +60,19 @@ def shutdown(*, context=None):
 
 def try_shutdown(*, context=None):
     """Shutdown rclpy if not already shutdown."""
+    global g_context_lock
+    global g_default_context
     if context is None:
-        context = get_default_context()
-    return context.try_shutdown()
+        # Replace the default context with a new one if shutdown was successful
+        # or if the context was already shutdown.
+        with g_context_lock:
+            if g_default_context is None:
+                g_default_context = Context()
+            g_default_context.try_shutdown()
+            if not g_default_context.ok():
+                g_default_context = None
+    else:
+        return context.try_shutdown()
 
 
 def get_rmw_implementation_identifier():