Panache doesn't support method reference

[DavideD]

Describe the bug

You can see this error by updating the hibernate-reactive-panche-quickstart.

Replace the FruitResource#delete with:

   @DELETE
   public Uni<Response> deleteAll() {
       return Panache.withTransaction(Fruit::deleteAll)
               .map(deleted -> Response.ok("Number of fruits deleted: " + deleted).build());
   }

Calling the rest point via HTTP will cause:

➜  hibernate-reactive-panache-quickstart git:(main) ✗ http DELETE localhost:8080/fruits
HTTP/1.1 500 Internal Server Error
Content-Type: application/json;charset=UTF-8
content-length: 189

{
    "code": 500,
    "error": "This method is normally automatically overridden in subclasses: did you forget to annotate your entity with @Entity?",
    "exceptionType": "java.lang.IllegalStateException"
}

Expected behavior

If I change the method to:

    @DELETE
    public Uni<Response> deleteAll() {
        return Panache
                .withTransaction( () -> Fruit.deleteAll() )
                .map( deleted -> Response.ok( "Number of fruits deleted: " + deleted ).build() );
    }

everything works as expected:

➜  hibernate-reactive-panache-quickstart git:(main) ✗ http DELETE localhost:8080/fruits
HTTP/1.1 200 OK
Content-Type: application/json;charset=UTF-8
content-length: 27

Number of fruits deleted: 3

[quarkus-bot]

/cc @FroMage (panache), @loicmathieu (panache)

[FroMage]

It's the Fruit::deleteAll that is the problem, I bet. It will work if you do () -> Fruit.deleteAll().

Besides transforming these lambdas with build transformers, I'm not sure how to fix this.

[DavideD]

Yes, that solved the issue.
Annoying, but if there's nothing we can do, I will just close it.

Thanks.

[FroMage]

There might be ways to solve those, I'd have to look at the bytecode. But I am not sure it's worth spending that time, as the error is pretty rare. I think you're the first to report it.

[DavideD]

It's OK, it's not critical. And, It's relatively easy to find workarounds.
If you don't have time maybe somewhere else will.

It's just annoying not to be able to use method reference.
Maybe a note on the website or in the documentation can be helpful.