Even approaching this as a mostly Java person, I'd have to say I'd expect C Ruby behavior. Not sure if there would be a good/easy way to provide a switch to JRuby that could toggle the behavior (or, alert you if it does something "unexpected" for Java - or Ruby for that matter).
Jerry On Nov 18, 11:04 pm, Charles Oliver Nutter <head...@headius.com> wrote: > Hiya folks. I have a conundrum. > > As you know, the JDK (at least in Hotspot/OpenJDK) does not close NIO > channels that are not closed explicitly...i.e. it does not close them > during finalization, and from looking at the source it appears they do > not define finalizers at all. I was under the impression that "Java" > still finalized IO channels for bad users, but found some whispers on > a couple forums that this behavior was changed around Java 1.5 because > of the impact of finalizers on GC. Mark Reinhold's name was mentioned, > and it is said that he helped make this change happen. > > In any case, the fact of the matter is that JVM users should not > depend on IO channels getting closed by a finalizer. I agree with that > decision...code that leaves IO to finalization is broken. > > My problem, put simply, is that C Ruby *does* close IO streams you > don't close on your own, and users may often expect that behavior. > > Up through the current release version of JRuby, we mimicked that > behavior by defining our own finalizer on our channel wrapper, and > everyone was happy. However, it's become apparent that by doing this > we have introduced subtle bugs over the years, such as when a channel > we don't own enters Ruby, we wrap it, and then our finalization closes > it prematurely. In an effort to fix that bug, I eliminated "close" > from our finalization of those channel wrappers, which is much cleaner > and I don't have to guess whether we own the channel or not. But now > we're not matching Ruby behavior, and I've had about half the folks I > polled say they'd find this change to be a major bug in JRuby. > > In between closing and not closing is a complicated dance of ownership > flags, wherein I'd try to track whether JRuby initiated the channel or > it came from outside, only closing in finalize in the former case. It > turns my stomach a bit just to think about doing that, but I fear it > might be my only option. > > So I'm stuck in a bad place. > > First off, can anyone confirm the reasons why Hotspot/OpenJDK doesn't > close NIO channels via a finalize method? How about other JVM/JDK > impls? > > Second...I'd like to know how you all might handle this situation. I'm > stuck between what I believe is a technically correct solution (not > closing in finalize) and the expectations of users who want arguably > broken code to behave as it does in C Ruby. > > - Charlie -- You received this message because you are subscribed to the Google Groups "JVM Languages" group. To post to this group, send email to jvm-langua...@googlegroups.com. To unsubscribe from this group, send email to jvm-languages+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/jvm-languages?hl=en.
