On Tue, 30 Jun 2026 15:58:10 GMT, Jorn Vernee <[email protected]> wrote:
> Unsafe was changed recently through: > https://github.com/openjdk/jdk/pull/31249 to no longer treat any non-zero > byte read as a `boolean` through Unsafe as `true`, but only treat the > 'canonical' representation, where only the least significant bit in the byte > is set, as `true`. > > This change inadvertently leaked out through the memory access var handles. A > user can write a `byte` into a memory segment (on or off-heap), and then read > it back as a `boolean`, making this behavior change observable. Since the > fallback linker depends on the previous behavior in the implementation, the > tier5 test from the title was failing. But, there is really a gap in testing > here, and we can observe the difference in behavior when just using the > memory access parts of the API as well. > > It is important that the normalization of boolean values is the same in all > these scenarios: > - Normalizing a value returned from native code by a downcall > - Normalizing an argument passed by native code to an upcall stub > - Normalizing a value read from a memory segment using a var handle or the > MemorySegment::get accessor > > To that end, this patch tweaks the memory segment var handles for boolean > access to restore the old normalization behavior. I've also added the missing > testing for this case. > > --------- > - [x] I confirm that I make this contribution in accordance with the [OpenJDK > Interim AI Policy](https://openjdk.org/legal/ai). This pull request has now been integrated. Changeset: dca8681f Author: Jorn Vernee <[email protected]> URL: https://git.openjdk.org/jdk/commit/dca8681fb737a9a71ddb06169f6202ac1cf64be3 Stats: 184 lines in 5 files changed: 105 ins; 2 del; 77 mod 8386848: testBool in java/foreign/normalize/TestNormalize.java fails on Zero VM with expected [true] but found [false] Reviewed-by: mcimadamore, vlivanov ------------- PR: https://git.openjdk.org/jdk/pull/31727
