HQL no longer deals with empty collections as bind values for nullness predicates in junction with other predicates

While it is true that a collection_valued_input_parameter is the only allowed parameter in the IN clause, I think a collection parameter can be used in other contexts. Specifically to this case, the null comparison expression grammar is:

Now, the JPQL BNF does not have an explicit production for input_parameter, but I think it would be safe to assume that it means ‘any parameter type defined in the grammar’, which would include collection_valued_input_parameter. Obviously that is an interpretation and the grammar is ambiguous without that production, but in this specific case I believe that it makes sense to be able to determine whether a parameter, not a path_expression, is null or not in terms of whether the value that is passed through the parameter is null or not.

We have introduced a check for this unsupported behavior, you should now obtain a clear error message. See for additional details.

You want to do dynamic filtering, so why are you using a static HQL query? The HQL grammar also accepts other constructs which might fail at later stages, so just because it parses doesn’t mean it’s “supported”.

Multi-valued parameters are only allowed for the IN predicate. If you check the documentation, you will see that multi-valued parameters are only ever used in examples for the IN predicate:

In addition, the JPA specification explicitly states through the grammar that there is only one place where such a collection valued parameter is allowed, which is the IN predicate. Here the excerpt from the grammar:

It seems someone in the past found out that Hibernate 4 and 5 didn’t validate the uses of parameters well enough and started promoting this bad approach. Using a multi-valued parameter just happened to work by accident in other contexts, but was also producing garbage SQL in some cases. Until Hibernate 6 we simply didn’t have enough information in the AST to properly validate this and now that we do, many people complain that this doesn’t work anymore.

But you should be happy this doesn’t work anymore, because now you have the opportunity to fix your code and quite possibly get better performance from your query due to that.

Criteria API is not always possible to use, for example when using @Query in Spring Data repositories. The HQL grammar accepts the idiom and I could not find any reference in current documentation saying that that is not allowed.

This pattern is no longer allowed, you should avoid it and instead use Criteria API for conditional predicates. Please refer to 's comment in for more information.