Remove ExecutorStatus abstract class (#2835)

This removes the ExecutorStatus abstract class, instead using its only concrete implementation PollItem everywhere that ExecutorStatus was previously used.

This requires some circular imports to let type annotations work - some now annotate some things as PollItem rather than ExecutorStatus. This is done using from __future__ import annotations and import rather than from ... import ...

parsl/dataflow/job_error_handler.py

@@ -1,16 +1,19 @@
+from __future__ import annotations
+
 from typing import List, Dict
 
-from parsl.dataflow.executor_status import ExecutorStatus
+import parsl.dataflow.job_status_poller as jsp
+
 from parsl.executors.base import ParslExecutor
 from parsl.providers.base import JobStatus, JobState
 
 
 class JobErrorHandler:
-    def run(self, status: List[ExecutorStatus]):
+    def run(self, status: List[jsp.PollItem]):
         for es in status:
             self._check_irrecoverable_executor(es)
 
-    def _check_irrecoverable_executor(self, es: ExecutorStatus):
+    def _check_irrecoverable_executor(self, es: jsp.PollItem):
         if not es.executor.error_management_enabled:
             return
         es.executor.handle_errors(self, es.status)

parsl/dataflow/job_status_poller.py

@@ -5,7 +5,6 @@
 from typing import Dict, Sequence
 from typing import List  # noqa F401 (used in type annotation)
 
-from parsl.dataflow.executor_status import ExecutorStatus
 from parsl.dataflow.job_error_handler import JobErrorHandler
 from parsl.dataflow.strategy import Strategy
 from parsl.executors.base import ParslExecutor
@@ -15,10 +14,11 @@
 
 from parsl.utils import Timer
 
+
 logger = logging.getLogger(__name__)
 
 
-class PollItem(ExecutorStatus):
+class PollItem:
     def __init__(self, executor: ParslExecutor, dfk: "parsl.dataflow.dflow.DataFlowKernel"):
         self._executor = executor
         self._dfk = dfk

parsl/dataflow/strategy.py

@@ -1,10 +1,12 @@
+from __future__ import annotations
 import logging
 import time
 import math
 import warnings
 from typing import Dict, List, Optional
 
-from parsl.dataflow.executor_status import ExecutorStatus
+import parsl.dataflow.job_status_poller as jsp
+
 from parsl.executors import HighThroughputExecutor
 from parsl.executors.base import ParslExecutor
 from parsl.executors.status_handling import BlockProviderExecutor
@@ -134,7 +136,7 @@ def add_executors(self, executors):
         for executor in executors:
             self.executors[executor.label] = {'idle_since': None}
 
-    def _strategy_noop(self, status: List[ExecutorStatus]) -> None:
+    def _strategy_noop(self, status: List[jsp.PollItem]) -> None:
         """Do nothing.
         """
         logger.debug("strategy_noop: doing nothing")