On Thu, 18 Dec 2025 20:00:45 GMT, Alex Menkov <[email protected]> wrote:
> Updated implementation of ObjectReference.equals and ObjectReference.hashCode
> to comply the spec for value objects.
> Added the test for value object ctor debugging, the test verifies the
> behaviour is expected.
> There is an issue with instance filter, it till be fixed separately (it's not
> yet clear how it would be better to fix it)
>
> testing: tier1..4, hs-tier5-svc
src/jdk.jdi/share/classes/com/sun/tools/jdi/ObjectReferenceImpl.java line 150:
> 148: public boolean equals(Object obj) {
> 149: if (obj instanceof ObjectReferenceImpl other) {
> 150: if (ref() == other.ref() && super.equals(obj)) {
I'm wondering if the super.equals(obj) call is necessary. The way JDI is
implemetned, there is a 1-to-1 relationship between the ObjectID and the
ObjectReference. If the ObjectIDs match, then the ObjectRefernces instances
should be one in the same. So either one of these checks should be sufficient.
I don't think both are needed.
src/jdk.jdi/share/classes/com/sun/tools/jdi/ObjectReferenceImpl.java line 159:
> 157: } catch (JDWPException exc) {
> 158: throw exc.toJDIException();
> 159: }
So the downside here is that when we don't have equality w.r.t. ObjectIDs, we
do the heavyweight call over JDWP. A while back I did a scan of users of
equals() in the JDI implementation and jdb, and it seemed it was always done on
known subtypes (ClassLoaderReference, ThreadReference, ClassReference, etc). So
I doubt in practice you would ever see two value types being compared, unless
the debugger was doing it for some reason. So if you did limit this JDWP call
to value types, probably it would be rare to non-existent that it would ever be
called.
src/jdk.jdwp.agent/share/native/libjdwp/ObjectReferenceImpl.c line 410:
> 408:
> 409: ref = commonRef_idToRef(env, id);
> 410: (void)outStream_writeInt(out, objectHashCode(ref));
Interesting that the debug agent already has an objectHashCode() but there were
no users of it.
-------------
PR Review Comment:
https://git.openjdk.org/valhalla/pull/1834#discussion_r2632512266
PR Review Comment:
https://git.openjdk.org/valhalla/pull/1834#discussion_r2632527382
PR Review Comment:
https://git.openjdk.org/valhalla/pull/1834#discussion_r2632506961
