Broadcasting to a truncated cycle point can bring down a workflow

[MetRonnie]

Description

cylc broadcast is not performing sufficient validation of inputted cycle points.

Reproducible Example

Take any datetime cycling workflow, and broadcast using a cycle point that is truncated, e.g. using only the year of decade 05 instead of the full year 2005:

$ cylc broadcast datetime -p 050101T0000Z -s '[environment]FOO=1'
Broadcast set:
+ [05-01-01T00:00Z/root] [environment]FOO=1

Scheduler log:

INFO - Command "broadcast" received.
    broadcast(cycle_points=['050101T0000Z'], mode=put_broadcast, namespaces=['root'], settings=[{'environment': {'FOO': '1'}}])
INFO - Broadcast set:
    + [05-01-01T00:00Z/root] [environment]FOO=1
...
ERROR - Cannot compare truncated to non-truncated TimePoint: 05-01-01T00:00Z, 20050101T0000Z
    Traceback (most recent call last):
      File "~/cylc-flow/cylc/flow/scheduler_cli.py", line 689, in cylc_play
        asyncio.get_running_loop()
    RuntimeError: no running event loop
    During handling of the above exception, another exception occurred:
    Traceback (most recent call last):
      File "~/cylc-flow/cylc/flow/scheduler.py", line 652, in run_scheduler
        await self._main_loop()
      File "~/cylc-flow/cylc/flow/scheduler.py", line 1534, in _main_loop
        self.broadcast_mgr.expire_broadcast(self.pool.get_min_point())
      File "~/cylc-flow/cylc/flow/broadcast_mgr.py", line 158, in expire_broadcast
        get_point(point_string) < cutoff_point):
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      File "~/cylc-flow/cylc/flow/cycling/__init__.py", line 137, in __lt__
        return self.__cmp__(other) == -1
               ^^^^^^^^^^^^^^^^^^^
      File "~/cylc-flow/cylc/flow/cycling/__init__.py", line 129, in __cmp__
        return self._cmp(other)
               ^^^^^^^^^^^^^^^^
      File "~/cylc-flow/cylc/flow/cycling/iso8601.py", line 127, in _cmp
        return self._iso_point_cmp(self.value, other.value, CALENDAR.mode)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      File "~/cylc-flow/cylc/flow/cycling/iso8601.py", line 135, in _iso_point_cmp
        return cmp(point, other_point)
               ^^^^^^^^^^^^^^^^^^^^^^^
      File "~/cylc-flow/cylc/flow/cycling/__init__.py", line 478, in cmp
        if self == other:
           ^^^^^^^^^^^^^
      File "~/micromamba/envs/cylc8/lib/python3.12/site-packages/metomi/isodatetime/data.py", line 1684, in __eq__
        return self._cmp(other, "eq")
               ^^^^^^^^^^^^^^^^^^^^^^
      File "~/micromamba/envs/cylc8/lib/python3.12/site-packages/metomi/isodatetime/data.py", line 1659, in _cmp
        raise ValueError(
    ValueError: Cannot compare truncated to non-truncated TimePoint: 05-01-01T00:00Z, 20050101T0000Z
CRITICAL - Workflow shutting down - Cannot compare truncated to non-truncated TimePoint: 05-01-01T00:00Z, 20050101T0000Z

This results in the scheduler crashing immediately on startup if you try to restart the workflow.

Expected Behaviour

cylc broadcast should fail if you pass it a truncated cycle point? It certainly shouldn't crash the scheduler.

[oliver-sanders]

Closed by #6414