Bad sql grammar for a single-element expression array in IN-clause

[ishulz]

I have a problem with generating a tuple-based expressions in my queryDsl generated SQL statements. All works fine if the expression in IN-clause is an array with more than one element (more than one expression) - the result looks like 'in ((?, ?), ... (?, ?))'. But if this array contains only one expression, IN-clause is just 'in (?, ?)' and this is a wrong SQL relation operator format.

This is a small test which showcases my problem:

    @ParameterizedTest(name = "[{index}] {0}")
    @CsvSource(delimiter = '|', value = {
        "Array contains 3 items | 3 | (?, ?) in ((?, ?), (?, ?), (?, ?))",
        "Array contains 2 items | 2 | (?, ?) in ((?, ?), (?, ?))",
        "Array contains 1 item   | 1 | (?, ?) in ((?, ?))"
    })
    public void test(String description, Integer count, String expected) {
        SimpleExpression<?>[] expressions = IntStream.range(0, count)
            .mapToObj(__ -> tuple(ConstantImpl.create(1), ConstantImpl.create(2)))
            .toArray(SimpleExpression[]::new);
        SQLSerializer serializer = new SQLSerializer(new Configuration(SQLTemplates.DEFAULT));
        BooleanExpression expression = tuple(ConstantImpl.create(0), ConstantImpl.create(1000))
            .in(expressions);
        serializer.handle(expression);
        assertThat(serializer.toString())
            .isEqualTo(expected);
    }


    public SimpleExpression<Object> tuple(Expression<?>... args) {
        return Expressions.template(Object.class, "({0}, {1})", args);
    }

This test fails on the 'Array contains 1 item' case (two other cases are successful):

Expected :(?, ?) in ((?, ?))
Actual   :(?, ?) in (?, ?)

but select * from someTable where (a, b) in (1, 2) is definitely a bad grammar SQL statement.

Looks like I have done something wrong - I was not able to make one-element array of expressions for IN-clause to be rendered properly - to the in ((?, ?)) pattern. Is it possible somehow to make queryDsl render a single-element array of expressions in the properly nested '((?, ?))' patterm?