Reintroduce `Specification.where(Specification)`

[mp911de]

See #3893 and user feedback:

Specifically, the static where(...) method now expects a PredicateSpecification instead of a Specification. This causes compile-time errors in existing projects that rely on Specification builders.

Would it be possible to provide an overload of where(...) that still accepts Specification (delegating internally to PredicateSpecification), or any kind of polymorphic support? This would greatly simplify migration by avoiding a large-scale refactor of existing specifications.

We should consider reintroducing Specification.where(Specification) to simplify the migration to Spring Data JPA 4.0.

[nam0oo]

Hi, I'm interested in working on this issue.

I've reviewed the background and agree that reintroducing the Specification.where(Specification) overload is a great enhancement for backward compatibility.

I can prepare a pull request with the required changes and unit tests. Please let me know if I can take this on and be assigned.

Thank you! 🙂

[injae-kim]

Fix PR: #3998 👍 PTAL :)