FATAL: ReleaseSavepoint: unexpected state SUBABORT_RESTART

[darold]

When a nested write statement from a SELECT function fail the fatal error in subject is thrown. Code to reproduce:

LOAD 'pg_statement_rollback.so';
SET pg_statement_rollback.enabled TO on;
SET pg_statement_rollback.savepoint_name TO 'aze';
SET pg_statement_rollback.enable_writeonly TO on;

DROP SCHEMA IF EXISTS testrsl CASCADE;
CREATE SCHEMA testrsl;

SET search_path TO testrsl,public;

SET log_min_duration_statement TO -1;
SET log_statement TO 'all';
SET log_duration TO off;
SET client_min_messages TO LOG;

CREATE FUNCTION test_insert_fail() RETURNS integer AS $$
BEGIN
    INSERT INTO tbl_rsl VALUES (2, 'two');
    INSERT INTO tbl_rsl VALUES ('three', 3);
    RETURN 1;
END
$$ LANGUAGE plpgsql;
\echo Test internal automatic savepoint with a failing DO block
BEGIN;
DROP TABLE IF EXISTS tbl_rsl;
CREATE TABLE tbl_rsl(id integer, val varchar(256));
INSERT INTO tbl_rsl VALUES (1, 'one');
DO $$ BEGIN PERFORM test_insert_fail(); END $$;
ROLLBACK TO SAVEPOINT aze;
DELETE FROM tbl_rsl WHERE id = 1;
SELECT * FROM tbl_rsl; -- Should show 0 record
COMMIT;

DROP SCHEMA testrsl CASCADE;