On 8/9/2022 11:56 PM, Peter Levart wrote:
On Sun, 7 Aug 2022 08:14:58 GMT, Alan Bateman <al...@openjdk.org> wrote:
Sorry for joining late. I noticed that modsHashCode is a private method and it
takes Iterable as a parameter. But everywhere it is called, a Set is passed to
it. So why not just calling the set.hashCode() and be done with it? It may be
even more optimal in some cases.
There's a lot going on here as the hash code is generated at link time and we
also want it to be reproducible across builds. We also had a CDS bug with the
the way that Enum objects were archived - Ioi has fixed that in JDK 19 so we
have one less thing to be concerned about now.
Ah, I see. Enum.hashCode() is identity hash code. I have been beaten by that in
the past and apparently this is a sore point for many. I wonder if it could be
changed. Is unstable hashCode (accross JVM instances) a feature here or just
unfortunate implementation detail?
We've gotten a few issues filed about Enum.hashCode() over the years,
one more recent one is
JDK-8050217: Enum.hashCode() should return ordinal value for the
enum, for better consistency
Current thinking per that issue is the present behavior is more of a
feature than a bug.
-Joe
