Fix duplicate task triggers

changes.d/6625.fix.md

@@ -0,0 +1 @@
+Efficiency improvement: avoid storing duplicate information on graph triggers.

cylc/flow/task_trigger.py

@@ -14,7 +14,11 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from typing import TYPE_CHECKING, Tuple
+from typing import (
+    TYPE_CHECKING,
+    Optional,
+    Tuple,
+)
 
 from cylc.flow.cycling.loader import (
     get_interval,
@@ -38,21 +42,28 @@ class TaskTrigger:
     """Class representing an upstream dependency.
 
     Args:
-        task_name (str): The name of the upstream task.
-        cycle_point_offset (str): String representing the offset of the
+        task_name: The name of the upstream task.
+        cycle_point_offset: String representing the offset of the
             upstream task (e.g. -P1D) if this dependency is not an absolute
             one. Else None.
-        output (str): The task state / output for this trigger e.g. succeeded.
+        output: The task state / output for this trigger e.g. succeeded.
 
     """
 
     __slots__ = ['task_name', 'cycle_point_offset', 'output',
                  'offset_is_irregular', 'offset_is_absolute',
                  'offset_is_from_icp', 'initial_point']
 
-    def __init__(self, task_name, cycle_point_offset, output,
-                 offset_is_irregular=False, offset_is_absolute=False,
-                 offset_is_from_icp=False, initial_point=None):
+    def __init__(
+        self,
+        task_name: str,
+        cycle_point_offset: Optional[str],
+        output: str,
+        offset_is_irregular: bool = False,
+        offset_is_absolute: bool = False,
+        offset_is_from_icp: bool = False,
+        initial_point: 'Optional[PointBase]' = None,
+    ):
         self.task_name = task_name
         self.cycle_point_offset = cycle_point_offset
         self.output = output
@@ -64,9 +75,10 @@ def __init__(self, task_name, cycle_point_offset, output,
         #   2000, 20000101T0600Z, 2000-01-01T06:00+00:00, ...
         # AND NON-ABSOLUTE IRREGULAR:
         #   -PT6H+P1D, T00, ...
-        if (self.offset_is_irregular and any(
-                self.cycle_point_offset.startswith(c)
-                for c in ['P', '+', '-', 'T'])):
+        if self.offset_is_irregular and any(
+            self.cycle_point_offset.startswith(c)  # type: ignore[union-attr]
+            for c in ['P', '+', '-', 'T']
+        ):
             self.offset_is_absolute = False
 
     def get_parent_point(self, from_point):
@@ -147,7 +159,28 @@ def __str__(self):
         else:
             return '%s:%s' % (self.task_name, self.output)
 
-    __repr__ = __str__
+    def __repr__(self) -> str:
+        """
+        >>> TaskTrigger('', '', '')
+        <TaskTrigger ...>
+        """
+        return f"<{type(self).__name__} {self}>"
+
+    def __hash__(self) -> int:
+        return hash((
+            self.task_name,
+            self.cycle_point_offset,
+            self.output,
+            self.offset_is_irregular,
+            self.offset_is_from_icp,
+            self.offset_is_absolute,
+            self.initial_point,
+        ))
+
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, TaskTrigger):
+            return NotImplemented
+        return hash(self) == hash(other)
 
     @staticmethod
     def standardise_name(name):

cylc/flow/taskdef.py

@@ -183,7 +183,7 @@ def __init__(self, name, rtcfg, start_point, initial_point):
         self.dependencies: Dict[SequenceBase, List[Dependency]] = {}
         self.outputs = {}  # {output: (message, is_required)}
         self.graph_children: Dict[
-            SequenceBase, Dict[str, List[Tuple[str, TaskTrigger]]]
+            SequenceBase, Dict[str, Set[Tuple[str, TaskTrigger]]]
         ] = {}
         self.graph_parents: Dict[
             SequenceBase, Set[Tuple[str, TaskTrigger]]
@@ -250,8 +250,8 @@ def add_graph_child(
         self.graph_children.setdefault(
             sequence, {}
         ).setdefault(
-            trigger.output, []
-        ).append((taskname, trigger))
+            trigger.output, set()
+        ).add((taskname, trigger))
 
     def add_graph_parent(
         self, trigger: 'TaskTrigger', parent: str, sequence: 'SequenceBase'

pytest.ini

@@ -27,6 +27,7 @@ addopts = --verbose
     # disable pytest-tornasync because it conflicts with pytest-asyncio's auto mode
     -p no:tornado
     -m "not linkcheck"
+verbosity_assertions = 2
 testpaths =
     cylc/flow/
     tests/unit/

tests/integration/test_graphql.py

@@ -287,6 +287,7 @@ async def test_edges(harness):
         'graphql',
         {'request_string': 'query { edges { id } }'}
     )
+    ret['edges'].sort(key=lambda x: x['id'])
     assert ret == {
         'edges': [
             {'id': id_}

tests/integration/test_taskdef.py

@@ -0,0 +1,46 @@
+# THIS FILE IS PART OF THE CYLC WORKFLOW ENGINE.
+# Copyright (C) NIWA & British Crown (Met Office) & Contributors.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from cylc.flow.config import WorkflowConfig
+from cylc.flow.pathutil import get_workflow_run_dir
+from cylc.flow.scheduler_cli import RunOptions
+from cylc.flow.task_outputs import TASK_OUTPUT_SUCCEEDED
+from cylc.flow.workflow_files import WorkflowFiles
+
+
+def test_graph_children(flow):
+    """TaskDef.graph_children should not include duplicates.
+
+    https://github.com/cylc/cylc-flow/issues/6619#issuecomment-2668932069
+    """
+    wid = flow({
+        'scheduling': {
+            'graph': {
+                'R1': 'foo | bar<n> => fin',
+            },
+        },
+        'task parameters': {
+            'n': '1..3',
+        },
+    })
+    config = WorkflowConfig(
+        wid, get_workflow_run_dir(wid, WorkflowFiles.FLOW_FILE), RunOptions()
+    )
+    foo = config.taskdefs['foo']
+    graph_children = list(foo.graph_children.values())[0]
+    assert [name for name, _ in graph_children[TASK_OUTPUT_SUCCEEDED]] == [
+        'fin'
+    ]

tests/unit/test_task_trigger.py

@@ -14,9 +14,16 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from cylc.flow.cycling.loader import get_point, get_sequence
-from cylc.flow.task_trigger import TaskTrigger, Dependency
+from cylc.flow.cycling.integer import IntegerPoint
+from cylc.flow.cycling.loader import (
+    get_point,
+    get_sequence,
+)
 from cylc.flow.task_outputs import TaskOutputs
+from cylc.flow.task_trigger import (
+    Dependency,
+    TaskTrigger,
+)
 
 
 def test_check_with_cycle_point():
@@ -171,3 +178,11 @@ def test_str(set_cycling_type):
 
     trigger = TaskTrigger('name', None, 'output')
     assert str(trigger) == 'name:output'
+
+
+def test_eq():
+    args = ('foo', '+P1', 'succeeded')
+    assert TaskTrigger(*args) == TaskTrigger(*args)
+    assert TaskTrigger(*args) != TaskTrigger(
+        *args, initial_point=IntegerPoint('1')
+    )