We are working on the migration from WildFly 26.1.2 to 27.0.0 for several large applications (totaling millions of lines of code). With this also comes the migration from Hibernate ORM 5.3.28 to 6.1.5. During some pioneering work for one of these applications, we’ve already identified 4 blocking (for us) regressions in Hibernate ORM (HHH-15694, HHH-15699, HHH-15708 and HHH-15716). Of these, HHH-15708 is particularly troublesome as it is preventing us from running about 90% of our test suite. The other issues we can work around in our tests by disabling batch fetching and entity and query caching (which is fine for tests only), but for HHH-15708 we do not see a viable workaround.
We’ve looked at the exception and the code in LazyTableGroup and it seems it is trying to navigate the path beyond where it should have. However this piece of code goes beyond our understanding of the Hibernate ORM internals. We could really use some help with trying to find a fix or a temporary workaround that would allow us to continue testing. Given the fact that we’ve only covered about 10% of one of the smaller applications, we suspect we will hit more issues. We’d rather find and report those as soon as possible to allow us to continue with the migration.