On Tue, 1 Jun 2021 09:30:40 GMT, Jaroslav Tulach <github.com+26887752+jaroslavtul...@openjdk.org> wrote:
> There doesn't seem to be much support for the complete changes in #4245. To > get at least something useful from that endeavor I have extracted the test > for existing behavior of `-XX:+PreserveAllAnnotations` and I am offering it > in this pull request without any changes to the JVM behavior. To share the information... I contacted one of the original authors of Java annotations, but he doesn't remember anything about the option. Here's the conversation... On Thu, Jun 3, 2021 at 11:53 PM Peter Levart <peter.lev...@gmail.com> wrote: > > There is an undocumented JVM flag called > "-XX+PreserveAllAnnotations" > which according to JVM code affects the way > "RuntimeInvisibleAnnotations" kind of class attributes are > treated at > runtime. Normally they are ignored (since they normally contain > only > metadata for annotation types with CLASS retention), but when > this flag > is passed to JVM, such attributes are also passed to > AnnotationParser > together with "RuntimeVisibleAnnotations" kind of class > attributes. > > So the question is: "What was the original intent of this JVM > flag". A > debate sprung in a review thread on JDK GitHub and some say that > this is > probably just a "leftover from an early implementation" and are > proposing to deprecate and remove it. Others (me mostly) see some > sense > in the feature as it allows migrating an annotation type from > CLASS > retention to RUNTIME without recompiling all the classes that use > the > annotation. Do you happen to know the original intent of this JVM > flag? On Fri, Jun 4, 2021 at 6:54 AM Neal Gafter <n...@gafter.com> wrote: > > I don’t recall that flag, but my suspicion is that it was used to > assist testing. > If you ask me, I think the ecosystem would be better without it. On 04/06/2021 15:56, Neal Gafter wrote: > > One more thing. You don’t have to recompile uses of an annotation to > migrate > from class to runtime retention. You only have to recompile the > attribute declaration. On Fri, Jun 4, 2021 at 7:15 AM Peter Levart <peter.lev...@gmail.com> wrote: > > Not really. The AnnotationParser does filter out annotations based on > current "retention" > of annotation type which is just a meta-annotation on the annotation > type, so it would appear > that only the annotation declaration has to be recompiled, but as I > described, the annotation > uses in classes that use the annotation get compiled into two kinds of > class attributes: > RuntimeVisibleAnnotations (those with RUNTIME retention) and > RuntimeInvisibleAnnotations > (those with CLASS retention). Only those from RuntimeVisibleAnnotations > are passed to > AnnotationParser at runtime unless this VM flag is given which makes the > VM pass a concatenation > of RuntimeVisibleAnnotations and RuntimeInvisibleAnnotations to the > AnnotationParser. > So merely changing the annotation retention and recompiling the > annotation declaration is not enough. > You have to also either recompile annotation uses or pass this VM flag. > So I was wondering if the flag was actually meant for this purpose. On 04/06/2021 17:30, Neal Gafter wrote: > > Got it. I don't remember anything about the VM flag, but I doubt it was > designed to be used for this purpose. ------------- PR: https://git.openjdk.java.net/jdk/pull/4280
