Change Proctitle to IDLE after an Error (#7863)

python/ray/_raylet.pyx

@@ -473,10 +473,10 @@ cdef execute_task(
             if isinstance(error, RayTaskError):
                 # Avoid recursive nesting of RayTaskError.
                 failure_object = RayTaskError(function_name, backtrace,
-                                              error.cause_cls)
+                                              error.cause_cls, proctitle=title)
             else:
                 failure_object = RayTaskError(function_name, backtrace,
-                                              error.__class__)
+                                              error.__class__, proctitle=title)
             errors = []
             for _ in range(c_return_ids.size()):
                 errors.append(failure_object)

python/ray/worker.py

@@ -1344,8 +1344,10 @@ def disconnect(exiting_interpreter=False):
 @contextmanager
 def _changeproctitle(title, next_title):
     setproctitle.setproctitle(title)
-    yield
-    setproctitle.setproctitle(next_title)
+    try:
+        yield
+    finally:
+        setproctitle.setproctitle(next_title)
 
 
 def register_custom_serializer(cls,