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From "Colin P. McCabe" <cmcc...@apache.org>
Subject Re: Protocol Buffers version
Date Tue, 19 May 2015 16:59:26 GMT
I agree that the protobuf 2.4.1 -> 2.5.0 transition could have been
handled a lot better by Google.  Specifically, since it was an
API-breaking upgrade, it should have been a major version bump for the
Java library version.  I also feel that removing the download links
for the old versions of the native libraries was careless, and
certainly burned some of our Hadoop users.

However, I don't see any reason to believe that protobuf 2.6 will not
be wire-compatible with earlier versions.  Google has actually been
pretty good about preserving wire-compatibility... just not about API
compatibility.  If we want to get a formal statement from the project,
we can, but I would be pretty shocked if they decided to change the
protocol in a backwards-incompatible way in a minor version release.

I do think there are some potential issues for our users of bumping
the library version in a minor Hadoop release.  Until we implement
full dependency isolation for Hadoop, there may be some disruptions to
end-users from changing Java dependency versions.  Similarly, users
will need to install a new native protobuf library version as well.
So I think we should bump the protobuf versions in Hadoop 3.0, but not
in 2.x.

cheers,
Colin

On Fri, May 15, 2015 at 4:55 AM, Alan Burlison <Alan.Burlison@oracle.com> wrote:
> On 15/05/2015 09:44, Steve Loughran wrote:
>
>> Now: why do you want to use a later version of protobuf.jar? Is it
>> because "it is there"? Or is there a tangible need?
>
>
> No, it's because I'm looking at this from a platform perspective: We have
> other consumers of ProtoBuf beside Hadoop and we'd obviously like to
> minimise the versions of PB that we ship, and preferably just ship the
> latest version. The fact that PB seems to often be incompatible across
> releases is an issue as it makes upgrading and dropping older versions
> problematic.
>
> --
> Alan Burlison
> --

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