On Thu, 10 Jul 2025 03:12:27 GMT, Serguei Spitsyn <sspit...@openjdk.org> wrote:
>> The VM option -XX:AllowRedefinitionToAddDeleteMethods was added in JDK 13 as >> a temporary backward compatibility flag under JDK-8192936 and was >> immediately marked as Deprecate. The fix is to obsolete this option in JDK >> 26 and expire in JDK 27. >> >> TBD: Need to submit a related CSR. >> >> There are two concerns which may require some negotiation with the Runtime >> (@coleenp @dcubed-ojdk @dholmes-ora) and SQE (@lmesnik) teams: >> - Class redefinition/retransformation can impact lambda expressions which >> are supported with private methods >> - Many tests depend on this VM option and are being removed. I'm not sure >> if it is okay to completely remove those e may want another way to handle >> this (e.g. problem-listing the impacted tests for now). >> >> Testing: >> - mach5 tiers 1-6 are good >> - may need to run mach5 tiers > 6 > > Serguei Spitsyn has updated the pull request incrementally with one > additional commit since the last revision: > > corrected one assert message This involved a lot more code than I had envisaged. The test situation seems problematic as it suggests to me that we have required functionality (redefine a method containing a lambda expression) that is not possible without the flag. And it seems this flag is also being used in the wild e.g. https://blog.picnic.nl/embracing-java-17-heres-what-we-learned-69779d95fdf2 > As of Java 16, JDK internals are strongly encapsulated by default ([JEP > 396](https://openjdk.java.net/jeps/396)). These and other changes mean that > some dependencies now > [require](https://github.com/reactor/BlockHound/issues/33) additional JVM > flags such as --add-opens and -XX:+AllowRedefinitionToAddDeleteMethods to > function properly. We updated our shared build system such that teams can > configure these flags in a single place, ensuring that test and production > runtimes remain in sync. With more info in https://github.com/reactor/BlockHound/issues/33 So I am quite concerned that this "workaround" has become entrenched. src/hotspot/share/prims/jvmtiRedefineClasses.cpp line 4053: > 4051: } > 4052: > 4053: void VM_RedefineClasses::compute_matching_methods() { I can't see that this method actually still does anything useful. ?? src/hotspot/share/runtime/arguments.cpp line 525: > 523: // -------------- Deprecated Flags -------------- > 524: // --- Non-alias flags - sorted by obsolete_in then expired_in: > 525: { "AllowRedefinitionToAddDeleteMethods", JDK_Version::jdk(13), > JDK_Version::jdk(26), JDK_Version::jdk(27) }, Please move this line to before line 535 (ParallelRefProcEnabled) so that we are sorted on obsolete_in as required. ------------- PR Review: https://git.openjdk.org/jdk/pull/26232#pullrequestreview-3004272187 PR Review Comment: https://git.openjdk.org/jdk/pull/26232#discussion_r2196808392 PR Review Comment: https://git.openjdk.org/jdk/pull/26232#discussion_r2196813023
