Release tasks from hidden pool even if workflow paused.

CHANGES.md

@@ -110,6 +110,11 @@ renamed to `CYLC_WORKFLOW_ID`. `CYLC_WORKFLOW_NAME` re-added as
 [#4443](https://github.com/cylc/cylc-flow/pull/4443) - fix for slow polling
 generating an incorrect submit-failed result.
 
+[#4436](https://github.com/cylc/cylc-flow/pull/4436) -
+If the workflow is paused, hold tasks just before job prep.
+Distinguish between succeeded and expired state icons in `cylc tui`.
+Spawn parentless tasks out the runahead limit immediately.
+
 [#4421](https://github.com/cylc/cylc-flow/pull/4421) -
 Remove use of the `ps` system call (fixes a bug reported with Alpine Linux).
 

cylc/flow/scheduler.py

@@ -1235,23 +1235,33 @@ def release_queued_tasks(self):
             itask.waiting_on_job_prep
         ]
 
-        if (not self.is_paused and
-                self.stop_mode is None and self.auto_restart_time is None):
-            # Add newly released tasks to those still preparing.
-            self.pre_submit_tasks += self.pool.release_queued_tasks()
-            if self.pre_submit_tasks:
-                self.is_updated = True
-                self.task_job_mgr.task_remote_mgr.rsync_includes = (
-                    self.config.get_validated_rsync_includes())
-                for itask in self.task_job_mgr.submit_task_jobs(
-                        self.workflow,
-                        self.pre_submit_tasks,
-                        self.curve_auth,
-                        self.client_pub_key_dir,
-                        self.config.run_mode('simulation')):
-                    # TODO log flow labels here (beware effect on ref tests)
-                    LOG.info('[%s] -triggered off %s',
-                             itask, itask.state.get_resolved_dependencies())
+        # Add newly released tasks to those still preparing.
+        self.pre_submit_tasks += self.pool.release_queued_tasks()
+
+        if (
+            self.pre_submit_tasks and
+            not self.is_paused and
+            self.stop_mode is None and
+            self.auto_restart_time is None
+        ):
+            # Start the job submission process.
+            self.is_updated = True
+
+            self.task_job_mgr.task_remote_mgr.rsync_includes = (
+                self.config.get_validated_rsync_includes())
+
+            for itask in self.task_job_mgr.submit_task_jobs(
+                self.workflow,
+                self.pre_submit_tasks,
+                self.curve_auth,
+                self.client_pub_key_dir,
+                self.config.run_mode('simulation')
+            ):
+                # TODO log flow labels here (beware effect on ref tests)
+                LOG.info(
+                    '[%s] -triggered off %s',
+                    itask, itask.state.get_resolved_dependencies()
+                )
 
     def process_workflow_db_queue(self):
         """Update workflow DB."""
@@ -1424,6 +1434,9 @@ async def main_loop(self):
         while True:  # MAIN LOOP
             tinit = time()
 
+            # Useful for debugging core scheduler issues:
+            # self.pool.log_task_pool(logging.CRITICAL)
+
             if self.pool.do_reload:
                 # Re-initialise data model on reload
                 self.data_store_mgr.initiate_data_model(reloaded=True)
@@ -1437,7 +1450,7 @@ async def main_loop(self):
 
             self.process_command_queue()
 
-            if not self.is_paused and self.pool.release_runahead_tasks():
+            if self.pool.release_runahead_tasks():
                 self.is_updated = True
                 self.reset_inactivity_timer()
 
@@ -1488,6 +1501,7 @@ async def main_loop(self):
                 self.xtrigger_mgr.housekeep(self.pool.get_tasks())
 
             self.pool.set_expired_tasks()
+
             self.release_queued_tasks()
 
             if self.pool.sim_time_check(self.message_queue):

cylc/flow/task_job_mgr.py

@@ -101,8 +101,9 @@
     TaskRemoteMgr
 )
 from cylc.flow.task_state import (
-    TASK_STATUS_RUNNING,
+    TASK_STATUS_PREPARING,
     TASK_STATUS_SUBMITTED,
+    TASK_STATUS_RUNNING,
     TASK_STATUSES_ACTIVE
 )
 from cylc.flow.wallclock import (
@@ -219,8 +220,11 @@ def prep_submit_task_jobs(self, workflow, itasks, check_syntax=True):
         prepared_tasks = []
         bad_tasks = []
         for itask in itasks:
-            prep_task = self._prep_submit_task_job(workflow, itask,
-                                                   check_syntax=check_syntax)
+            if itask.state.reset(TASK_STATUS_PREPARING):
+                self.data_store_mgr.delta_task_state(itask)
+                self.workflow_db_mgr.put_update_task_state(itask)
+            prep_task = self._prep_submit_task_job(
+                workflow, itask, check_syntax=check_syntax)
             if prep_task:
                 prepared_tasks.append(itask)
             elif prep_task is False:
@@ -254,6 +258,7 @@ def submit_task_jobs(self, workflow, itasks, curve_auth,
         if not prepared_tasks:
             return bad_tasks
         auth_itasks = {}  # {platform: [itask, ...], ...}
+
         for itask in prepared_tasks:
             platform_name = itask.platform['name']
             auth_itasks.setdefault(platform_name, [])