Guard against stale due_time overwrite (Feature 07 fix) (#87)

tests/test_materialize.py

@@ -545,7 +545,7 @@ def test_materialize_uses_single_presence_snapshot_mid_walk(tmp_path) -> None:
     _with_db(tmp_path, "materialize-presence-snapshot.db")(_body)
 
 
-def test_materialize_stores_snapshot_due_time_not_live(tmp_path) -> None:
+def test_materialize_skips_stale_due_time_mid_walk(tmp_path) -> None:
     async def _body(database):
         children = ChildrenDao(database)
         child = await children.create("Ada", NOW)
@@ -566,21 +566,64 @@ def test_materialize_stores_snapshot_due_time_not_live(tmp_path) -> None:
             )
 
         # The window's due_time is edited to 10:15 between the input
-        # snapshot and the insert.  The walk must store the SNAPSHOT's
-        # 09:00, not the live 10:15 — the batch is governed entirely by
-        # the coherent snapshot it read.
+        # snapshot and the insert.  The walk's snapshotted 09:00 no
+        # longer matches the live 10:15, so the tuple is SKIPPED rather
+        # than writing a due_time that has already been superseded.
         count = await _materialize_with_change(
             database, start_iso, end_iso, _edit_due_time
         )
-        assert count == 3
+        assert count == 0
+        assert await QuestInstancesDao(database).list_by_date_range(
+            child.id, start_iso, end_iso
+        ) == []
+        return count
+
+    _with_db(tmp_path, "materialize-stale-due-time.db")(_body)
+
+
+def test_materialize_does_not_overwrite_regenerated_due_time(tmp_path) -> None:
+    async def _body(database):
+        children = ChildrenDao(database)
+        child = await children.create("Ada", NOW)
+
+        today = datetime.date.today()
+        start_iso = today.isoformat()
+        end_iso = (today + datetime.timedelta(days=2)).isoformat()
+
+        created = await create_quest_definition(
+            database,
+            "Daily chore",
+            ScheduleRule(rule_type=RuleType.DAILY, start_date=start_iso),
+            [child.id],
+            [("morning", "09:00")],
+        )
+
+        async def _edit_and_regenerate():
+            # A window-time edit + regeneration land after the stale walk
+            # read its input snapshot: the window moves to 10:15 and the
+            # regeneration upserts the newer due_time across the horizon.
+            await QuestDefinitionsDao(database).upsert_window(
+                created.definition.id, "morning", due_time="10:15"
+            )
+            await regenerate_for_definition(database, created.definition.id)
+
+        # The stale walk (snapshot due_time 09:00) then resumes.  It must
+        # SKIP these tuples — its snapshotted 09:00 no longer matches the
+        # live 10:15 — so the regeneration's newer due_time survives and
+        # is NOT overwritten by the stale value.
+        count = await _materialize_with_change(
+            database, start_iso, end_iso, _edit_and_regenerate
+        )
+        assert count == 0
+
         records = await QuestInstancesDao(database).list_by_date_range(
             child.id, start_iso, end_iso
         )
         assert len(records) == 3
-        assert {r.due_time for r in records} == {"09:00"}
+        assert {r.due_time for r in records} == {"10:15"}
         return records
 
-    _with_db(tmp_path, "materialize-snapshot-due-time.db")(_body)
+    _with_db(tmp_path, "materialize-regenerated-due-time.db")(_body)
 
 
 def test_materialize_honours_overrides(tmp_path) -> None: