On 2016-01-22 19:43, Stuart Marks wrote:
On 1/22/16 7:44 AM, Claes Redestad wrote:
It would seem the assessment that serialVersionUID is not needed when
using the serial proxy pattern might be misguided (or is this a bug in
ObjectInputStream)?
It is debate-able whether this is a test bug or not. But I think
we should not change the serialVersionUID for this class, whether
truly Serializable or not. Even though in practice it is not all
that useful.
Can you please revert the serialization parts of the change, and
rerun the test? To see if still passes or fails.
I backed out the serial version UID change and reran the test, same
thing.
I dug deeper, as this is a bit vexxing...
While a static field does not in and of itself cause the generated
UID to change,
the private ZERO_LENGTH_ENUM_ARRAY is being accessed from
SerializationProxy
class, thus javac generates a package-private synthetic method
(access$000) which
will be accounted for when generating serialVersionUID. That's
unfortunate.
I ran a few experiments to confirm this:
- Adding a package-private static method to EnumSet makes the test fail
- Adding any static field and the test keep passing
So it seems our options here are limited.
I think this is a bug in the test (BogusEnumSet.java).
EnumSet, a class in the runtime, should never appear in a serialized
stream, thus it shouldn't have to declare a serialVersionUID in order
to remain compatible with anything.
The test deliberately attempts to create a serialized stream that
should never occur in actual use, so the test should be responsible
for constructing that stream properly. Unfortunately, the test doesn't
actually construct that stream; instead it's a bunch of hex constants.
It's tedious but not difficult to patch the constants with the
modified value. I've appended a patch below that does this, along with
removing EnumSet's serialVersionUID and restoring the @SuppressWarnings.
I can post a webrev if this doesn't come through properly.
s'marks
Thanks Stuart!
I've posted a webrev including your changes here:
http://cr.openjdk.java.net/~redestad/8148044/webrev.03/
If there's a preference for this version I'll push it after the weekend.
Thanks!
/Claes
