-- sift.verify raises ERRCODE_INDEX_CORRUPTED, and never crashes, on a damaged position stream:
-- 0xFF bytes are written over every block of a positioned index in turn, at three offsets (the index is small and the position blocks of
-- format 4 lie at other places than the records did: one offset can miss them all)
CREATE EXTENSION pg_sift_test CASCADE;
CREATE TABLE vp (id serial PRIMARY KEY, body text);
INSERT INTO vp (body) SELECT 'w' || (i % 7) || ' x' || (i % 101) || ' common doc' || i % 50 || ' common' FROM generate_series(1, 3000) i;
CREATE INDEX vp_idx ON vp USING sift (body);
CREATE TABLE vp_verdict (blk int, state text, msg text);

DO $$
DECLARE
	nb int := pg_relation_size('vp_idx') / 8192;
	o int;
BEGIN
	FOREACH o IN ARRAY ARRAY[1600, 4200, 6200] LOOP
		FOR b IN 2 .. nb - 1 LOOP
			PERFORM sift._test_poke('vp_idx', b, o, -1, 8);
			BEGIN
				PERFORM sift.verify('vp_idx');
				INSERT INTO vp_verdict VALUES (b, 'ok', NULL);
			EXCEPTION WHEN OTHERS THEN
				INSERT INTO vp_verdict VALUES (b, SQLSTATE, SQLERRM);
			END;
			REINDEX INDEX vp_idx;
		END LOOP;
	END LOOP;
END $$;

SELECT count(*) > 0 AS blocks_poked, bool_and(state IN ('ok', 'XX002')) AS ok_or_corrupt,
	count(*) FILTER (WHERE msg ~ 'position (record|stream)') > 0 AS position_damage_found FROM vp_verdict;
SELECT sift.verify('vp_idx', true);

DROP TABLE vp, vp_verdict;
DROP EXTENSION pg_sift_test;
DROP EXTENSION pg_sift;