ALTER TABLE tasks ADD COLUMN merge_state TEXT NOT NULL DEFAULT '';
ALTER TABLE tasks ADD COLUMN merge_by TEXT NOT NULL DEFAULT '';
UPDATE tasks SET
	merge_state = CASE
		WHEN finalizing != '' THEN 'finalizing'
		WHEN merging_by != '' AND merge_after_turn = 1 THEN 'claimed'
		WHEN merging_by != '' THEN 'turn'
		WHEN merge_queued_by != '' THEN 'held'
		ELSE ''
	END,
	merge_by = CASE
		WHEN finalizing != '' THEN finalizing
		WHEN merging_by != '' THEN merging_by
		ELSE merge_queued_by
	END;
UPDATE tasks SET merge_queued_at = '' WHERE merge_state != 'held';
ALTER TABLE tasks DROP COLUMN merge_queued_by;
ALTER TABLE tasks DROP COLUMN merging_by;
ALTER TABLE tasks DROP COLUMN merge_after_turn;
ALTER TABLE tasks DROP COLUMN finalizing;