main loop: re-raise CylcError as MainLoopPluginException

cylc/flow/main_loop/__init__.py

@@ -53,6 +53,17 @@
 from cylc.flow.exceptions import CylcError, UserInputError
 
 
+class MainLoopPluginException(Exception):
+    """Raised in-place of CylcError exceptions.
+    
+    Note:
+        * Not an instace of CylcError as that is used for controlled
+          shutdown e.g. SchedulerStop.
+
+    """
+
+
+
 def load_plugins(config, additional_plugins=None):
     """Load main loop plugins from the suite/global configuration.
 
@@ -112,10 +123,12 @@ async def _wrapper(fcn, scheduler, state, timings=False):
     start_time = time()
     try:
         await fcn(scheduler, state)
+    except CylcError as exc:
+        # allow CylcErrors through (e.g. SchedulerStop)
+        # NOTE: the `from None` bit gets rid of this gunk:
+        # > During handling of the above exception another exception
+        raise MainLoopPluginException(exc) from None
     except Exception as exc:
-        if isinstance(exc, CylcError):
-            # allow CylcErrors through (e.g. SchedulerStop)
-            raise
         LOG.error(f'Error in main loop plugin {sig}')
         LOG.exception(exc)
     else:

cylc/flow/main_loop/health_check.py

@@ -42,15 +42,18 @@ async def during(scheduler, _):
 
 def _check_suite_run_dir(scheduler):
     if not os.path.exists(scheduler.suite_run_dir):
-        raise CylcError('Suite run directory cannot be accessed.')
+        raise CylcError(
+            'Suite run directory does not exist:'
+            f' {scheduler.suite_run_dir}'
+        )
 
 
 def _check_contact_file(scheduler):
     try:
         contact_data = suite_files.load_contact_file(
             scheduler.suite)
         if contact_data != scheduler.contact_data:
-            raise AssertionError('contact file modified')
+            raise CylcError('contact file modified')
     except (AssertionError, IOError, ValueError, SuiteServiceFileError):
         raise CylcError(
             '%s: contact file corrupted/modified and may be left'

cylc/flow/tests/main_loop/main_loop.py

@@ -9,8 +9,9 @@
 from cylc.flow import CYLC_LOG
 from cylc.flow.exceptions import CylcError
 from cylc.flow.main_loop import (
-    load_plugins,
+    MainLoopPluginException,
     _wrapper,
+    load_plugins,
     before,
     during,
     after
@@ -132,7 +133,7 @@ async def test_coro(*_):
         None,
         None
     )
-    with pytest.raises(CylcError):
+    with pytest.raises(MainLoopPluginException):
         asyncio.run(coro)
 
 

tests/events/48-suite-aborted.t

@@ -27,7 +27,7 @@ suite_run_fail "${TEST_NAME_BASE}-run" \
 cylc cat-log "${SUITE_NAME}" >'log'
 grep_ok 'CRITICAL - Suite shutting down - contact file modified' 'log'
 cmp_ok "${SUITE_RUN_DIR}/handler.out" <<'__OUT__'
-contact file modified
+aborted contact file modified
 __OUT__
 
 purge_suite "${SUITE_NAME}"