[OU-FIX] event: remap cancelled events onto Ended before dropping the Cancelled stage

openupgrade_scripts/scripts/event/19.0.1.9/pre-migration.py

@@ -37,8 +37,51 @@ def event_event_badge_format(env):
     )
 
 
+def remap_cancelled_stage(env):
+    """
+    19.0 drops the Cancelled stage in favour of kanban_state='cancel'.
+    event.event.stage_id is ondelete='restrict', so remap cancelled events
+    onto the surviving Ended stage (flagged cancelled) before removing the
+    stage and its ir_model_data row. Pure SQL: event's models are not in
+    the registry during its own pre-migration.
+    """
+    env.cr.execute(
+        """
+        SELECT name, res_id FROM ir_model_data
+        WHERE module = 'event' AND model = 'event.stage'
+          AND name IN ('event_stage_cancelled', 'event_stage_done')
+        """
+    )
+    stages = dict(env.cr.fetchall())
+    cancelled = stages.get("event_stage_cancelled")
+    done = stages.get("event_stage_done")
+    if not cancelled:
+        return
+    if done:
+        openupgrade.logged_query(
+            env.cr,
+            """
+            UPDATE event_event
+            SET stage_id = %s, kanban_state = 'cancel'
+            WHERE stage_id = %s
+            """,
+            (done, cancelled),
+        )
+    openupgrade.logged_query(
+        env.cr, "DELETE FROM event_stage WHERE id = %s", (cancelled,)
+    )
+    openupgrade.logged_query(
+        env.cr,
+        """
+        DELETE FROM ir_model_data
+        WHERE module = 'event' AND name = 'event_stage_cancelled'
+        """,
+    )
+
+
 @openupgrade.migrate()
 def migrate(env, version):
     openupgrade.copy_columns(env.cr, _copy_columns)
     openupgrade.add_fields(env, _added_fields)
     event_event_badge_format(env)
+    remap_cancelled_stage(env)