Aug 4 - Update code to follow up - MT11

migrations/versions/phase47_schedule_end_date.py

@@ -0,0 +1,73 @@
+"""phase47 — inspection schedule end date
+
+Ports single-tenant phase44 onto MT's `inspection_schedules` table. Adds:
+
+    end_date DATE NULL   -- last date this schedule may produce an occurrence
+
+Separates the two ideas that `next_run_at` was carrying at once. `next_run_at`
+is *mutable state* — InspectionSchedule.advance_due_date() rewrites it after
+every occurrence, whether the inspector completed a plan-mode schedule or the
+cron materialised an auto-mode one — whereas `end_date` is a *fixed boundary*
+set by the manager and never touched by the app. NULL means "repeat
+indefinitely", which is the behaviour every existing row has today, so there is
+no backfill and no schedule changes cadence on deploy.
+
+Applies to BOTH modes. Scoping it to plan mode would leave an auto schedule
+materialising inspections past its boundary forever, which is the exact failure
+the column exists to prevent.
+
+Only meaningful for recurring schedules; the create/edit routes force it to NULL
+when frequency == 'once' (a one-time schedule already ends by deactivating on
+completion) and reject an end date submitted against one.
+
+Uses an INFORMATION_SCHEMA column-existence check — safe to re-run on every
+tenant DB. Additive only: no existing column is renamed, retyped or dropped. In
+particular `next_run_at` keeps its name and its index — it is the API payload
+key (`next_due_date`) the iPad decodes and drives the cron.
+"""
+
+revision      = 'phase47_schedule_end_date'
+down_revision = 'phase46_schedule_recurrence'
+branch_labels = None
+depends_on    = None
+
+from alembic import op
+import sqlalchemy as sa
+
+
+_TABLE = 'inspection_schedules'
+
+
+def _table_exists(conn, table):
+    return conn.execute(sa.text(
+        "SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES "
+        "WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = :t"
+    ), {"t": table}).scalar() > 0
+
+
+def _column_exists(conn, table, column):
+    return conn.execute(sa.text(
+        "SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS "
+        "WHERE TABLE_SCHEMA = DATABASE() "
+        "AND TABLE_NAME = :t AND COLUMN_NAME = :c"
+    ), {"t": table, "c": column}).scalar() > 0
+
+
+def upgrade():
+    bind = op.get_bind()
+    if not _table_exists(bind, _TABLE):
+        return
+    if not _column_exists(bind, _TABLE, 'end_date'):
+        op.execute(sa.text(
+            f"ALTER TABLE {_TABLE} ADD COLUMN end_date DATE NULL AFTER next_run_at"
+        ))
+
+
+def downgrade():
+    bind = op.get_bind()
+    if not _table_exists(bind, _TABLE):
+        return
+    if _column_exists(bind, _TABLE, 'end_date'):
+        op.execute(sa.text(
+            f"ALTER TABLE {_TABLE} DROP COLUMN end_date"
+        ))