Aug 25 - Implement new function allow Director (internal & customer) to assign and inspection to another inspector

migrations/versions/phase53_followup_assignee.py

@@ -0,0 +1,68 @@
+"""phase53 — assign a follow-up re-inspection to a specific inspector
+
+Adds `inspections.follow_up_assigned_to` (FK -> users.id, ON DELETE SET NULL).
+
+Until now a follow-up implicitly belonged to whoever performed the original
+inspection: they were the one notified, and the mobile API only ever showed
+follow-ups where `inspector_id == the caller`. A director could not hand the
+re-inspection to somebody else.
+
+NULL means exactly what it meant before — the follow-up belongs to the
+inspection's own inspector — so every existing row keeps its current behaviour
+and no backfill is needed. `Inspection.follow_up_owner` is the one place that
+resolves assignee-or-inspector.
+
+**This is the THIRD FK from inspections to users** (inspector_id,
+follow_up_requested_by, and now this). Rule 86: any relationship between the two
+tables must pin `foreign_keys` explicitly or the mapper is ambiguous — and it
+raises on first ORM *use*, not at import, so the app starts fine and then every
+request 500s. `Inspection.follow_up_assignee` pins it; `User.inspections` was
+already pinned in phase46.
+
+INFORMATION_SCHEMA checks — safe to re-run.
+"""
+
+revision      = 'phase53_followup_assignee'
+down_revision = 'phase52_template_contracts'
+branch_labels = None
+depends_on    = None
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def _has_column(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 _has_constraint(conn, table, name):
+    return conn.execute(sa.text(
+        "SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS "
+        "WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = :t AND CONSTRAINT_NAME = :n"
+    ), {'t': table, 'n': name}).scalar() > 0
+
+
+def upgrade():
+    conn = op.get_bind()
+    if not _has_column(conn, 'inspections', 'follow_up_assigned_to'):
+        op.add_column('inspections',
+                      sa.Column('follow_up_assigned_to', sa.Integer, nullable=True))
+    if not _has_constraint(conn, 'inspections', 'fk_inspections_followup_assignee'):
+        op.create_foreign_key(
+            'fk_inspections_followup_assignee', 'inspections', 'users',
+            ['follow_up_assigned_to'], ['id'], ondelete='SET NULL',
+        )
+
+
+def downgrade():
+    conn = op.get_bind()
+    if _has_constraint(conn, 'inspections', 'fk_inspections_followup_assignee'):
+        op.drop_constraint('fk_inspections_followup_assignee', 'inspections',
+                           type_='foreignkey')
+    if _has_column(conn, 'inspections', 'follow_up_assigned_to'):
+        # Assignments are discarded; every follow-up reverts to belonging to the
+        # inspection's own inspector, which is where it started.
+        op.drop_column('inspections', 'follow_up_assigned_to')