From d378e3a046f12d1a29484493eee7bc93fb79832f Mon Sep 17 00:00:00 2001
From: Tim Pillinger <26465611+wxtim@users.noreply.github.com>
Date: Mon, 22 Apr 2024 14:45:26 +0100
Subject: [PATCH] ensure that sim mode won't fail if an invalid date is
 broadcast to it

---
 cylc/flow/run_modes/simulation.py             | 37 +++++++++----------
 .../integration/run_modes/test_simulation.py  |  4 ++
 2 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/cylc/flow/run_modes/simulation.py b/cylc/flow/run_modes/simulation.py
index f2eb708aad3..3197857bec6 100644
--- a/cylc/flow/run_modes/simulation.py
+++ b/cylc/flow/run_modes/simulation.py
@@ -59,7 +59,9 @@ def submit_task_job(
     Returns:
         True - indicating that TaskJobManager need take no further action.
     """
-    configure_sim_mode(rtconfig)
+    configure_sim_mode(
+        rtconfig,
+        itask.tdef.rtconfig['simulation']['fail cycle points'])
     itask.summary['started_time'] = now[0]
     task_job_mgr._set_retry_timers(itask, rtconfig)
     itask.mode_settings = ModeSettings(
@@ -156,21 +158,12 @@ def __init__(
         if not rtconfig:
             rtconfig = itask.tdef.rtconfig
         if rtconfig and rtconfig != itask.tdef.rtconfig:
-            try:
-                rtconfig["simulation"][
-                    "fail cycle points"
-                ] = parse_fail_cycle_points(
-                    rtconfig["simulation"]["fail cycle points"]
-                )
-            except PointParsingError as exc:
-                # Broadcast Fail CP didn't parse
-                LOG.warning(
-                    'Broadcast fail cycle point was invalid:\n'
-                    f'    {exc.args[0]}'
-                )
-                rtconfig['simulation'][
-                    'fail cycle points'
-                ] = itask.tdef.rtconfig['simulation']['fail cycle points']
+            rtconfig["simulation"][
+                "fail cycle points"
+            ] = parse_fail_cycle_points(
+                rtconfig["simulation"]["fail cycle points"],
+                itask.tdef.rtconfig['simulation']['fail cycle points']
+            )
 
         # Calculate simulation info:
         self.simulated_run_length = (
@@ -183,7 +176,7 @@ def __init__(
         self.timeout = started_time + self.simulated_run_length
 
 
-def configure_sim_mode(rtc):
+def configure_sim_mode(rtc, fallback):
     """Adjust task defs for simulation and dummy mode.
 
     """
@@ -197,7 +190,8 @@ def configure_sim_mode(rtc):
     rtc["simulation"][
         "fail cycle points"
     ] = parse_fail_cycle_points(
-        rtc["simulation"]["fail cycle points"]
+        rtc["simulation"]["fail cycle points"],
+        fallback
     )
 
 
@@ -240,7 +234,7 @@ def disable_platforms(
 
 
 def parse_fail_cycle_points(
-    f_pts_orig: List[str]
+    f_pts_orig: List[str], fallback
 ) -> 'Union[None, List[PointBase]]':
     """Parse `[simulation][fail cycle points]`.
 
@@ -275,6 +269,7 @@ def parse_fail_cycle_points(
                     LOG.warning(
                         f'Invalid ISO 8601 date representation: {point_str}'
                     )
+                    return fallback
     return f_pts
 
 
@@ -303,7 +298,9 @@ def sim_time_check(
         if itask.mode_settings is None:
             rtconfig = task_events_manager.broadcast_mgr.get_updated_rtconfig(
                 itask)
-            rtconfig = configure_sim_mode(rtconfig)
+            rtconfig = configure_sim_mode(
+                rtconfig,
+                itask.tdef.rtconfig['simulation']['fail cycle points'])
             itask.mode_settings = ModeSettings(
                 itask,
                 db_mgr,
diff --git a/tests/integration/run_modes/test_simulation.py b/tests/integration/run_modes/test_simulation.py
index 9ac2f651ddb..dd38a0eed59 100644
--- a/tests/integration/run_modes/test_simulation.py
+++ b/tests/integration/run_modes/test_simulation.py
@@ -423,6 +423,10 @@ async def test_settings_broadcast(
             'Invalid ISO 8601 date representation: higadfuhasgiurguj'
             in log.messages[-1])
 
+        # Check that the invalid broadcast hasn't
+        # changed the itask sim mode settings:
+        assert itask.mode_settings.sim_task_fails is True
+
         schd.broadcast_mgr.put_broadcast(
             ['1066'], ['one'], [{
                 'simulation': {'fail cycle points': '1'}