Demote invalid event handler error => warning (#6917)

Author: wxtim

changes.d/6197.fix.md

@@ -0,0 +1 @@
+Demote errors about invalid task event names to warnings

cylc/flow/config.py

@@ -1761,7 +1761,7 @@ def _check_task_event_names(self, taskdef: 'TaskDef') -> None:
                 taskdef.rtconfig['outputs'],
             )
             if invalid:
-                raise WorkflowConfigError(
+                LOG.warning(
                     "Invalid event name(s) for "
                     f"[runtime][{taskdef.name}][events]{setting}: "
                     + ', '.join(sorted(invalid))

tests/functional/events/36-task-event-bad-custom-template.t

@@ -19,7 +19,7 @@
 
 . "$(dirname "$0")/test_header"
 
-set_test_number 3
+set_test_number 4
 
 init_workflow "${TEST_NAME_BASE}" <<'__FLOW_CONFIG__'
 [scheduling]
@@ -36,11 +36,16 @@ cylc message -- ${CYLC_WORKFLOW_ID} ${CYLC_TASK_JOB} \
             lily = lily
             iris = iris
         [[[events]]]
-            handler events = rose, lily, iris, warning
+            handler events = rose, lily, iris, warning, arsenic
+            # (arsenic is an invalid event)
             handlers = echo %(message)s
 __FLOW_CONFIG__
 
-run_ok "${TEST_NAME_BASE}-validate" cylc validate "${WORKFLOW_NAME}"
+TEST_NAME="${TEST_NAME_BASE}-validate"
+run_ok "$TEST_NAME" cylc validate "${WORKFLOW_NAME}"
+
+dump_std "${TEST_NAME}"
+grep_ok 'WARNING - Invalid event name.*arsenic' "${TEST_NAME}.stderr"
 
 workflow_run_ok "${TEST_NAME_BASE}-run" \
     cylc play --debug --no-detach "${WORKFLOW_NAME}"

tests/functional/events/36-task-event-bad-custom-template/flow.cylc

@@ -671,3 +671,29 @@ async def test_invalid_starttask(one_conf, flow, scheduler, start):
     with pytest.raises(InputError, match='a///b'):
         async with start(schd):
             pass
+
+
+async def test_task_event_bad_custom_template(
+    flow, validate, scheduler, start, log_filter
+):
+    """Validation fails if task event handler has a bad custom template.
+    """
+    exception = (
+        r"bad task event handler template t1: echo %\(rubbish\)s:"
+        r" KeyError\('rubbish'\)"
+    )
+    events = {
+        'handlers': 'echo %(rubbish)s',
+        'handler events': 'succeeded'
+    }
+    wid = flow({
+        'scheduling': {'graph': {'R1': 't1'}},
+        'runtime': {'t1': {'events': events}},
+    })
+    with pytest.raises(WorkflowConfigError, match=exception):
+        validate(wid)
+
+    schd = scheduler(wid)
+    with pytest.raises(WorkflowConfigError, match=exception):
+        async with start(schd):
+            pass

tests/functional/events/36-task-event-bad-custom-template/reference.log

@@ -1791,8 +1791,8 @@ def test_val_wflow_event_names(item, tmp_flow_config, log_filter):
 
 
 @pytest.mark.parametrize('item', ['handler events', 'mail events'])
-def test_check_task_event_names(item, tmp_flow_config):
-    """"Any invalid task handler events raise an error."""
+def test_check_task_event_names(item, tmp_flow_config, log_filter):
+    """"Any invalid task handler events are warned about."""
     flow_file = tmp_flow_config('foo', f"""
         [scheduling]
             [[graph]]
@@ -1805,9 +1805,9 @@ def test_check_task_event_names(item, tmp_flow_config):
                 [[[outputs]]]
                     owl = who
     """)
-    with pytest.raises(WorkflowConfigError) as ex_info:
-        WorkflowConfig('foo', str(flow_file), ValidateOptions())
-    assert str(ex_info.value) == (
+
+    WorkflowConfig('foo', str(flow_file), ValidateOptions())
+    assert log_filter(contains=(
         f"Invalid event name(s) for [runtime][foo][events]{item}: "
         "badger, horse"
-    )
+    ))