Recompute runahead limit after cylc remove

CHANGES.md

@@ -36,6 +36,9 @@ Maintenance release.
 
 ### Fixes
 
+[#5192](https://github.com/cylc/cylc-flow/pull/5192) - Recompute runahead limit
+after use of `cylc remove`.
+
 [#5125](https://github.com/cylc/cylc-flow/pull/5125) - Allow rose-suite.conf
 changes to be considered by ``cylc reinstall``.
 

cylc/flow/task_pool.py

@@ -105,8 +105,8 @@ def __init__(
 
         self.main_pool: Pool = {}
         self.hidden_pool: Pool = {}
-        self.main_pool_list: List[TaskProxy] = []
-        self.hidden_pool_list: List[TaskProxy] = []
+        self._main_pool_list: List[TaskProxy] = []
+        self._hidden_pool_list: List[TaskProxy] = []
         self.main_pool_changed = False
         self.hidden_pool_changed = False
 
@@ -703,22 +703,24 @@ def get_all_tasks(self) -> List[TaskProxy]:
 
     def get_tasks(self) -> List[TaskProxy]:
         """Return a list of task proxies in the main pool."""
+        # Cached list only for use internally in this method.
         if self.main_pool_changed:
             self.main_pool_changed = False
-            self.main_pool_list = []
+            self._main_pool_list = []
             for _, itask_id_map in self.main_pool.items():
                 for __, itask in itask_id_map.items():
-                    self.main_pool_list.append(itask)
-        return self.main_pool_list
+                    self._main_pool_list.append(itask)
+        return self._main_pool_list
 
     def get_hidden_tasks(self) -> List[TaskProxy]:
         """Return a list of task proxies in the hidden pool."""
+        # Cached list only for use internally in this method.
         if self.hidden_pool_changed:
             self.hidden_pool_changed = False
-            self.hidden_pool_list = []
+            self._hidden_pool_list = []
             for itask_id_maps in self.hidden_pool.values():
-                self.hidden_pool_list.extend(list(itask_id_maps.values()))
-        return self.hidden_pool_list
+                self._hidden_pool_list.extend(list(itask_id_maps.values()))
+        return self._hidden_pool_list
 
     def get_tasks_by_point(self):
         """Return a map of task proxies by cycle point."""
@@ -1530,6 +1532,8 @@ def remove_tasks(self, items):
         itasks, _, bad_items = self.filter_task_proxies(items)
         for itask in itasks:
             self.remove(itask, 'request')
+        if self.compute_runahead():
+            self.release_runahead_tasks()
         return len(bad_items)
 
     def force_trigger_tasks(
@@ -1718,8 +1722,8 @@ def stop_flow(self, flow_num):
     def log_task_pool(self, log_lvl=logging.DEBUG):
         """Log content of task and prerequisite pools in debug mode."""
         for pool, name in [
-            (self.main_pool_list, "Main"),
-            (self.hidden_pool_list, "Hidden")
+            (self.get_tasks(), "Main"),
+            (self.get_hidden_tasks(), "Hidden")
         ]:
             if pool:
                 LOG.log(

tests/integration/test_task_pool.py

@@ -558,3 +558,21 @@ async def test_reload_stopcp(
         assert str(schd.pool.stop_point) == '2020'
         schd.command_reload_workflow()
         assert str(schd.pool.stop_point) == '2020'
+
+
+async def test_runahead_after_remove(
+    example_flow: Scheduler
+) -> None:
+    """The runahead limit should be recomputed after tasks are removed.
+
+    """
+    task_pool = example_flow.pool
+    assert int(task_pool.runahead_limit_point) == 4
+
+    # No change after removing an intermediate cycle.
+    task_pool.remove_tasks(['3/*'])
+    assert int(task_pool.runahead_limit_point) == 4
+
+    # Should update after removing the first point.
+    task_pool.remove_tasks(['1/*'])
+    assert int(task_pool.runahead_limit_point) == 5