job.py: Stop sending the result from a job through the pipe

This is not needed now that jobs run in the smae process, we can just
return the value from the method.

1 files changed, 8 insertions, 30 deletions

diff --git a/src/buildstream/_scheduler/jobs/job.py b/src/buildstream/_scheduler/jobs/job.py
index b2c65b6ba..3fde4148d 100644
--- a/src/buildstream/_scheduler/jobs/job.py
+++ b/src/buildstream/_scheduler/jobs/job.py
@@ -73,7 +73,6 @@ class _Envelope:
 class _MessageType(FastEnum):
     LOG_MESSAGE = 1
     ERROR = 2
-    RESULT = 3
 
 
 # Job()
@@ -177,8 +176,8 @@ class Job:
         loop = asyncio.get_event_loop()
 
         async def execute():
-            result = await loop.run_in_executor(None, self._child.child_action, pipe_w)
-            await self._parent_child_completed(result)
+            ret_code, self._result = await loop.run_in_executor(None, self._child.child_action, pipe_w)
+            await self._parent_child_completed(ret_code)
 
         self._task = loop.create_task(execute())
 
@@ -389,9 +388,6 @@ class Job:
             # reported from a child task in the main process, this global state
             # is currently managed in _exceptions.py
             set_last_task_error(envelope.message["domain"], envelope.message["reason"])
-        elif envelope.message_type is _MessageType.RESULT:
-            assert self._result is None
-            self._result = envelope.message
         else:
             assert False, "Unhandled message type '{}': {}".format(envelope.message_type, envelope.message)
 
@@ -548,7 +544,7 @@ class ChildJob:
                 with self._terminate_lock:
                     self._thread_id = threading.current_thread().ident
                     if self._should_terminate:
-                        return _ReturnCode.TERMINATED
+                        return _ReturnCode.TERMINATED, None
 
                 try:
                     # Try the task action
@@ -558,7 +554,7 @@ class ChildJob:
                     self.message(MessageType.SKIPPED, str(e), elapsed=elapsed, logfile=filename)
 
                     # Alert parent of skip by return code
-                    return _ReturnCode.SKIPPED
+                    return _ReturnCode.SKIPPED, None
                 except BstError as e:
                     elapsed = datetime.datetime.now() - timeinfo.start_time
                     retry_flag = e.temporary
@@ -585,7 +581,7 @@ class ChildJob:
 
                     # Set return code based on whether or not the error was temporary.
                     #
-                    return _ReturnCode.FAIL if retry_flag else _ReturnCode.PERM_FAIL
+                    return _ReturnCode.FAIL if retry_flag else _ReturnCode.PERM_FAIL, None
                 except Exception:  # pylint: disable=broad-except
 
                     # If an unhandled (not normalized to BstError) occurs, that's a bug,
@@ -597,24 +593,22 @@ class ChildJob:
 
                     self.message(MessageType.BUG, self.action_name, elapsed=elapsed, detail=detail, logfile=filename)
                     # Unhandled exceptions should permenantly fail
-                    return _ReturnCode.PERM_FAIL
+                    return _ReturnCode.PERM_FAIL, None
 
                 else:
                     # No exception occurred in the action
-                    self._child_send_result(result)
-
                     elapsed = datetime.datetime.now() - timeinfo.start_time
                     self.message(MessageType.SUCCESS, self.action_name, elapsed=elapsed, logfile=filename)
 
                     # Shutdown needs to stay outside of the above context manager,
                     # make sure we dont try to handle SIGTERM while the process
                     # is already busy in sys.exit()
-                    return _ReturnCode.OK
+                    return _ReturnCode.OK, result
                 finally:
                     self._thread_id = None
             except TerminateException:
                 self._thread_id = None
-                return _ReturnCode.TERMINATED
+                return _ReturnCode.TERMINATED, None
             finally:
                 self._pipe_w.close()
 
@@ -671,22 +665,6 @@ class ChildJob:
 
         self._send_message(_MessageType.ERROR, {"domain": domain, "reason": reason})
 
-    # _child_send_result()
-    #
-    # Sends the serialized result to the main process through the message pipe
-    #
-    # Args:
-    #    result (any): None, or a simple object (must be pickle-able, i.e.
-    #                  strings, lists, dicts, numbers, but not Element
-    #                  instances).
-    #
-    # Note: If None is passed here, nothing needs to be sent, the
-    #       result member in the parent process will simply remain None.
-    #
-    def _child_send_result(self, result):
-        if result is not None:
-            self._send_message(_MessageType.RESULT, result)
-
     # _child_message_handler()
     #
     # A Context delegate for handling messages, this replaces the