From 1542024cf386057de631ff36580c80d093ae6479 Mon Sep 17 00:00:00 2001
From: Ronnie Dutta <61982285+MetRonnie@users.noreply.github.com>
Date: Tue, 19 Mar 2024 17:36:15 +0000
Subject: [PATCH] Preserve n-window depth on reload

---
 changes.d/6029.feat.md                   |  1 +
 cylc/flow/data_store_mgr.py              | 10 +++++-----
 cylc/flow/network/resolvers.py           | 13 +++++++------
 tests/integration/test_data_store_mgr.py |  7 +++++++
 4 files changed, 20 insertions(+), 11 deletions(-)
 create mode 100644 changes.d/6029.feat.md

diff --git a/changes.d/6029.feat.md b/changes.d/6029.feat.md
new file mode 100644
index 00000000000..140424f6d03
--- /dev/null
+++ b/changes.d/6029.feat.md
@@ -0,0 +1 @@
+Workflow graph window extent is now preserved on reload.
diff --git a/cylc/flow/data_store_mgr.py b/cylc/flow/data_store_mgr.py
index 7a59e76d7a4..0d79fc22b57 100644
--- a/cylc/flow/data_store_mgr.py
+++ b/cylc/flow/data_store_mgr.py
@@ -463,7 +463,7 @@ class DataStoreMgr:
     ERR_PREFIX_JOBID_MATCH = 'No matching jobs found: '
     ERR_PREFIX_JOB_NOT_ON_SEQUENCE = 'Invalid cycle point for job: '
 
-    def __init__(self, schd):
+    def __init__(self, schd, n_edge_distance=1):
         self.schd = schd
         self.id_ = Tokens(
             user=self.schd.owner,
@@ -477,7 +477,7 @@ def __init__(self, schd):
         self.updated_state_families = set()
         # Update workflow state totals once more post delta application.
         self.state_update_follow_on = False
-        self.n_edge_distance = 1
+        self.n_edge_distance = n_edge_distance
         self.next_n_edge_distance = None
         self.latest_state_tasks = {
             state: deque(maxlen=LATEST_STATE_TASKS_QUEUE_SIZE)
@@ -530,7 +530,7 @@ def initiate_data_model(self, reloaded=False):
         """
         # Reset attributes/data-store on reload:
         if reloaded:
-            self.__init__(self.schd)
+            self.__init__(self.schd, self.n_edge_distance)
 
         # Static elements
         self.generate_definition_elements()
@@ -2110,11 +2110,11 @@ def _family_ascent_point_update(self, fp_id):
                 self.state_update_families.add(fam_node.first_parent)
             self.state_update_families.remove(fp_id)
 
-    def set_graph_window_extent(self, n_edge_distance):
+    def set_graph_window_extent(self, n_edge_distance: int) -> None:
         """Set what the max edge distance will change to.
 
         Args:
-            n_edge_distance (int):
+            n_edge_distance:
                 Maximum edge distance from active node.
 
         """
diff --git a/cylc/flow/network/resolvers.py b/cylc/flow/network/resolvers.py
index ea9bde97be2..5451ef501aa 100644
--- a/cylc/flow/network/resolvers.py
+++ b/cylc/flow/network/resolvers.py
@@ -839,24 +839,25 @@ def put_messages(
             )
         return (True, f'Messages queued: {len(messages)}')
 
-    def set_graph_window_extent(self, n_edge_distance):
+    def set_graph_window_extent(
+        self, n_edge_distance: int
+    ) -> Tuple[bool, str]:
         """Set data-store graph window to new max edge distance.
 
         Args:
-            n_edge_distance (int):
+            n_edge_distance:
                 Max edge distance 0..n from active node.
 
         Returns:
             tuple: (outcome, message)
 
-            outcome (bool)
+            outcome
                 True if command successfully queued.
-            message (str)
+            message
                 Information about outcome.
 
         """
         if n_edge_distance >= 0:
             self.schd.data_store_mgr.set_graph_window_extent(n_edge_distance)
             return (True, f'Maximum edge distance set to {n_edge_distance}')
-        else:
-            return (False, 'Edge distance cannot be negative')
+        return (False, 'Edge distance cannot be negative')
diff --git a/tests/integration/test_data_store_mgr.py b/tests/integration/test_data_store_mgr.py
index 78b24200634..65105d4b8a3 100644
--- a/tests/integration/test_data_store_mgr.py
+++ b/tests/integration/test_data_store_mgr.py
@@ -157,10 +157,17 @@ def test_increment_graph_window(harness):
 
 def test_initiate_data_model(harness):
     """Test method that generates all data elements in order."""
+    schd: Scheduler
     schd, data = harness
     assert len(data[WORKFLOW].task_proxies) == 2
     schd.data_store_mgr.initiate_data_model(reloaded=True)
     assert len(data[WORKFLOW].task_proxies) == 2
+    # Check n-window preserved on reload:
+    schd.data_store_mgr.set_graph_window_extent(2)
+    schd.data_store_mgr.update_data_structure()
+    assert schd.data_store_mgr.n_edge_distance == 2
+    schd.data_store_mgr.initiate_data_model(reloaded=True)
+    assert schd.data_store_mgr.n_edge_distance == 2
 
 
 async def test_delta_task_state(harness):