Derived delete queries not working for Spring Data JDBC

[LarsKaulen]

I try implementing a repository using Spring Data JDBC as described in the documentation, using an (embedded) HSQL database.

When using derived delete queries (see Example 6 in the linked documentation), I encounter two issues:

1. When trying to return the number of deleted records (domain class com.example.demo.db.User), I get a ClassCastException (java.lang.ClassCastException: com.example.demo.db.User cannot be cast to java.lang.Long).
2. When using a query with either void or with the domain object as return type, the method successfully completes, but the record is never deleted. It looks like only a SELECT statement is performed on the database, but not the DELETE statement.

It doesn't matter if I try to remove by id or by a custom attribute of my entity.
The default void deleteById(Integer id) method and using custom queries (with the @Query annotation) both works.
For other queries (e.g. findByUsername) everything seems to work.

I have created a minimal reproducer to showcase the problem: when running the com.example.demo.db.UserRepositoryTest class, the tests using the default method or the explicit query methods (those with @Query) work, but those with the derived queries fail.

Is this a bug or do I misunderstand/misconfigure something?

[schauder]

Duplicate of #771

[LarsKaulen]

Hi @schauder I also saw this issue but there it is stated that

Derived delete/removeByXxx queries work as expected for return type void

which isn't the case in my example. And the exception for long return value was also different.

But I guess #771 has developed into an accumulative issue regarding this? Maybe as long as #771 isn't fixed, there should be a note in the documentation, that the given examples actually aren't working...

[gregturn]

Duplicates #771.