Trigger and set: fix default flow assignment for n=0 tasks.

changes.d/6367.fix.md

@@ -0,0 +1 @@
+Fix bug where `cylc trigger` and `cylc set` would assign active flows to existing tasks by default.

cylc/flow/command_validation.py

@@ -30,7 +30,7 @@
 
 
 ERR_OPT_FLOW_VAL = "Flow values must be an integer, or 'all', 'new', or 'none'"
-ERR_OPT_FLOW_INT = "Multiple flow options must all be integer valued"
+ERR_OPT_FLOW_COMBINE = "Cannot combine --flow={0} with other flow values"
 ERR_OPT_FLOW_WAIT = (
     f"--wait is not compatible with --flow={FLOW_NEW} or --flow={FLOW_NONE}"
 )
@@ -39,40 +39,47 @@
 def flow_opts(flows: List[str], flow_wait: bool) -> None:
     """Check validity of flow-related CLI options.
 
-    Note the schema defaults flows to ["all"].
+    Note the schema defaults flows to [].
 
     Examples:
         Good:
+        >>> flow_opts([], False)
         >>> flow_opts(["new"], False)
         >>> flow_opts(["1", "2"], False)
         >>> flow_opts(["1", "2"], True)
 
         Bad:
         >>> flow_opts(["none", "1"], False)
         Traceback (most recent call last):
-        cylc.flow.exceptions.InputError: ... must all be integer valued
+        cylc.flow.exceptions.InputError: Cannot combine --flow=none with other
+        flow values
 
         >>> flow_opts(["cheese", "2"], True)
         Traceback (most recent call last):
         cylc.flow.exceptions.InputError: ... or 'all', 'new', or 'none'
 
         >>> flow_opts(["new"], True)
         Traceback (most recent call last):
-        cylc.flow.exceptions.InputError: ...
+        cylc.flow.exceptions.InputError: --wait is not compatible with
+        --flow=new or --flow=none
 
     """
+    if not flows:
+        return
+
+    flows = [val.strip() for val in flows]
+
     for val in flows:
-        val = val.strip()
-        if val in [FLOW_NONE, FLOW_NEW, FLOW_ALL]:
+        if val in {FLOW_NONE, FLOW_NEW, FLOW_ALL}:
             if len(flows) != 1:
-                raise InputError(ERR_OPT_FLOW_INT)
+                raise InputError(ERR_OPT_FLOW_COMBINE.format(val))
         else:
             try:
                 int(val)
             except ValueError:
-                raise InputError(ERR_OPT_FLOW_VAL.format(val))
+                raise InputError(ERR_OPT_FLOW_VAL)
 
-    if flow_wait and flows[0] in [FLOW_NEW, FLOW_NONE]:
+    if flow_wait and flows[0] in {FLOW_NEW, FLOW_NONE}:
         raise InputError(ERR_OPT_FLOW_WAIT)
 
 

cylc/flow/data_store_mgr.py

@@ -1419,7 +1419,7 @@ def apply_task_proxy_db_history(self):
             itask, is_parent = self.db_load_task_proxies[relative_id]
             itask.submit_num = submit_num
             flow_nums = deserialise_set(flow_nums_str)
-            # Do not set states and outputs for future tasks in flow.
+            # Do not set states and outputs for inactive tasks in flow.
             if (
                     itask.flow_nums and
                     flow_nums != itask.flow_nums and

cylc/flow/network/schema.py

@@ -1998,17 +1998,20 @@ class Arguments:
 class FlowMutationArguments:
     flow = graphene.List(
         graphene.NonNull(Flow),
-        default_value=[FLOW_ALL],
+        default_value=[],
         description=sstrip(f'''
-            The flow(s) to trigger these tasks in.
-
-            This should be a list of flow numbers OR a single-item list
-            containing one of the following three strings:
-
-            * {FLOW_ALL} - Triggered tasks belong to all active flows
-              (default).
-            * {FLOW_NEW} - Triggered tasks are assigned to a new flow.
-            * {FLOW_NONE} - Triggered tasks do not belong to any flow.
+            The flow(s) to trigger/set these tasks in.
+
+            By default:
+            * active tasks (n=0) keep their existing flow assignment
+            * inactive tasks (n>0) get assigned all active flows
+
+            Otherwise you can assign (inactive tasks) or add to (active tasks):
+            * a list of integer flow numbers
+            or one of the following strings:
+            * {FLOW_ALL} - all active flows
+            * {FLOW_NEW} - an automatically generated new flow number
+            * {FLOW_NONE} - (ignored for active tasks): no flow
         ''')
     )
     flow_wait = Boolean(

cylc/flow/scripts/trigger.py

@@ -17,19 +17,12 @@
 
 """cylc trigger [OPTIONS] ARGS
 
-Force tasks to run despite unsatisfied prerequisites.
+Force tasks to run regardless of prerequisites.
 
 * Triggering an unqueued waiting task queues it, regardless of prerequisites.
 * Triggering a queued task submits it, regardless of queue limiting.
 * Triggering an active task has no effect (it already triggered).
 
-Incomplete and active-waiting tasks in the n=0 window already belong to a flow.
-Triggering them queues them to run (or rerun) in the same flow.
-
-Beyond n=0, triggered tasks get all current active flow numbers by default, or
-specified flow numbers via the --flow option. Those flows - if/when they catch
-up - will see tasks that ran after triggering event as having run already.
-
 Examples:
   # trigger task foo in cycle 1234 in test
   $ cylc trigger test//1234/foo
@@ -39,6 +32,21 @@
 
   # start a new flow by triggering 1234/foo in test
   $ cylc trigger --flow=new test//1234/foo
+
+Flows:
+  Active tasks (in the n=0 window) already belong to a flow.
+  * by default, if triggered, they run in the same flow
+  * or with --flow=all, they are assigned all active flows
+  * or with --flow=INT or --flow=new, the original and new flows are merged
+  * (--flow=none is ignored for active tasks)
+
+  Inactive tasks (n>0) do not already belong to a flow.
+  * by default they are assigned all active flows
+  * otherwise, they are assigned the --flow value
+
+  Note --flow=new increments the global flow counter with each use. If it
+  takes multiple commands to start a new flow use the actual flow number
+  after the first command (you can read it from the scheduler log).
 """
 
 from functools import partial

cylc/flow/task_pool.py

@@ -1280,35 +1280,35 @@ def set_hold_point(self, point: 'PointBase') -> None:
     def hold_tasks(self, items: Iterable[str]) -> int:
         """Hold tasks with IDs matching the specified items."""
         # Hold active tasks:
-        itasks, future_tasks, unmatched = self.filter_task_proxies(
+        itasks, inactive_tasks, unmatched = self.filter_task_proxies(
             items,
             warn=False,
             future=True,
         )
         for itask in itasks:
             self.hold_active_task(itask)
-        # Set future tasks to be held:
-        for name, cycle in future_tasks:
+        # Set inactive tasks to be held:
+        for name, cycle in inactive_tasks:
             self.data_store_mgr.delta_task_held((name, cycle, True))
-        self.tasks_to_hold.update(future_tasks)
+        self.tasks_to_hold.update(inactive_tasks)
         self.workflow_db_mgr.put_tasks_to_hold(self.tasks_to_hold)
         LOG.debug(f"Tasks to hold: {self.tasks_to_hold}")
         return len(unmatched)
 
     def release_held_tasks(self, items: Iterable[str]) -> int:
         """Release held tasks with IDs matching any specified items."""
         # Release active tasks:
-        itasks, future_tasks, unmatched = self.filter_task_proxies(
+        itasks, inactive_tasks, unmatched = self.filter_task_proxies(
             items,
             warn=False,
             future=True,
         )
         for itask in itasks:
             self.release_held_active_task(itask)
-        # Unhold future tasks:
-        for name, cycle in future_tasks:
+        # Unhold inactive tasks:
+        for name, cycle in inactive_tasks:
             self.data_store_mgr.delta_task_held((name, cycle, False))
-        self.tasks_to_hold.difference_update(future_tasks)
+        self.tasks_to_hold.difference_update(inactive_tasks)
         self.workflow_db_mgr.put_tasks_to_hold(self.tasks_to_hold)
         LOG.debug(f"Tasks to hold: {self.tasks_to_hold}")
         return len(unmatched)
@@ -1887,7 +1887,7 @@ def set_prereqs_and_outputs(
 
         Task matching restrictions (for now):
         - globs (cycle and name) only match in the pool
-        - future tasks must be specified individually
+        - inactive tasks must be specified individually
         - family names are not expanded to members
 
         Uses a transient task proxy to spawn children. (Even if parent was
@@ -1908,27 +1908,28 @@ def set_prereqs_and_outputs(
             flow_descr: description of new flow
 
         """
-        flow_nums = self._get_flow_nums(flow, flow_descr)
-        if flow_nums is None:
-            # Illegal flow command opts
-            return
-
-        # Get matching pool tasks and future task definitions.
-        itasks, future_tasks, unmatched = self.filter_task_proxies(
+        # Get matching pool tasks and inactive task definitions.
+        itasks, inactive_tasks, unmatched = self.filter_task_proxies(
             items,
             future=True,
             warn=False,
         )
 
+        flow_nums = self._get_flow_nums(flow, flow_descr)
+
+        # Set existing task proxies.
         for itask in itasks:
-            # Existing task proxies.
             self.merge_flows(itask, flow_nums)
             if prereqs:
                 self._set_prereqs_itask(itask, prereqs, flow_nums)
             else:
                 self._set_outputs_itask(itask, outputs)
 
-        for name, point in future_tasks:
+        # Spawn and set inactive tasks.
+        if not flow:
+            # default: assign to all active flows
+            flow_nums = self._get_active_flow_nums()
+        for name, point in inactive_tasks:
             tdef = self.config.get_taskdef(name)
             if prereqs:
                 self._set_prereqs_tdef(
@@ -2015,7 +2016,7 @@ def _set_prereqs_itask(
     def _set_prereqs_tdef(
         self, point, taskdef, prereqs, flow_nums, flow_wait
     ):
-        """Spawn a future task and set prerequisites on it."""
+        """Spawn an inactive task and set prerequisites on it."""
 
         itask = self.spawn_task(taskdef.name, point, flow_nums, flow_wait)
         if itask is None:
@@ -2063,38 +2064,30 @@ def remove_tasks(self, items):
         return len(bad_items)
 
     def _get_flow_nums(
-            self,
-            flow: List[str],
-            meta: Optional[str] = None,
-    ) -> Optional[Set[int]]:
-        """Get correct flow numbers given user command options."""
-        if set(flow).intersection({FLOW_ALL, FLOW_NEW, FLOW_NONE}):
-            if len(flow) != 1:
-                LOG.warning(
-                    f'The "flow" values {FLOW_ALL}, {FLOW_NEW} & {FLOW_NONE}'
-                    ' cannot be used in combination with integer flow numbers.'
-                )
-                return None
-            if flow[0] == FLOW_ALL:
-                flow_nums = self._get_active_flow_nums()
-            elif flow[0] == FLOW_NEW:
-                flow_nums = {self.flow_mgr.get_flow_num(meta=meta)}
-            elif flow[0] == FLOW_NONE:
-                flow_nums = set()
-        else:
-            try:
-                flow_nums = {
-                    self.flow_mgr.get_flow_num(
-                        flow_num=int(n), meta=meta
-                    )
-                    for n in flow
-                }
-            except ValueError:
-                LOG.warning(
-                    f"Ignoring command: illegal flow values {flow}"
-                )
-                return None
-        return flow_nums
+        self,
+        flow: List[str],
+        meta: Optional[str] = None,
+    ) -> Set[int]:
+        """Return flow numbers corresponding to user command options.
+
+        Arg should have been validated already during command validation.
+
+        In the default case (--flow option not provided), stick with the
+        existing flows (so return empty set) - NOTE this only applies for
+        active tasks.
+
+        """
+        if flow == [FLOW_NONE]:
+            return set()
+        if flow == [FLOW_ALL]:
+            return self._get_active_flow_nums()
+        if flow == [FLOW_NEW]:
+            return {self.flow_mgr.get_flow_num(meta=meta)}
+        # else specific flow numbers:
+        return {
+            self.flow_mgr.get_flow_num(flow_num=int(n), meta=meta)
+            for n in flow
+        }
 
     def _force_trigger(self, itask):
         """Assumes task is in the pool"""
@@ -2157,30 +2150,28 @@ def force_trigger_tasks(
               unless flow-wait is set.
 
         """
-        # Get flow numbers for the tasks to be triggered.
-        flow_nums = self._get_flow_nums(flow, flow_descr)
-        if flow_nums is None:
-            return
-
-        # Get matching tasks proxies, and matching future task IDs.
+        # Get matching tasks proxies, and matching inactive task IDs.
         existing_tasks, future_ids, unmatched = self.filter_task_proxies(
             items, future=True, warn=False,
         )
 
-        # Trigger existing tasks.
+        flow_nums = self._get_flow_nums(flow, flow_descr)
+
+        # Trigger active tasks.
         for itask in existing_tasks:
             if itask.state(TASK_STATUS_PREPARING, *TASK_STATUSES_ACTIVE):
                 LOG.warning(f"[{itask}] ignoring trigger - already active")
                 continue
             self.merge_flows(itask, flow_nums)
             self._force_trigger(itask)
 
-        # Spawn and trigger future tasks.
+        # Spawn and trigger inactive tasks.
+        if not flow:
+            # default: assign to all active flows
+            flow_nums = self._get_active_flow_nums()
         for name, point in future_ids:
-
             if not self.can_be_spawned(name, point):
                 continue
-
             submit_num, _, prev_fwait = (
                 self._get_task_history(name, point, flow_nums)
             )
@@ -2321,13 +2312,13 @@ def filter_task_proxies(
         )
         future_matched: 'Set[Tuple[str, PointBase]]' = set()
         if future and unmatched:
-            future_matched, unmatched = self.match_future_tasks(
+            future_matched, unmatched = self.match_inactive_tasks(
                 unmatched
             )
 
         return matched, future_matched, unmatched
 
-    def match_future_tasks(
+    def match_inactive_tasks(
         self,
         ids: Iterable[str],
     ) -> Tuple[Set[Tuple[str, 'PointBase']], List[str]]:

tests/functional/cylc-set/04-switch/flow.cylc

@@ -1,4 +1,4 @@
-# Set outputs of future task to direct the flow at an optional branch point.
+# Set outputs of inactive task to direct the flow at an optional branch point.
 
 [scheduler]
     [[events]]

tests/functional/cylc-set/05-expire/flow.cylc

@@ -1,4 +1,4 @@
-# Expire a future task, so it won't run.
+# Expire an inactive task, so it won't run.
 
 [scheduler]
     [[events]]