Re: [protobuf] proto3 backward compatibility problem

[sam sun]

I knew it, because yarn depends on proto2 but my lib depends on proto3. The 
reason is that proto3 runtime doesn't keep backward compatibility. The 
problem can be reproduced if set option java_generate_equals_and_hash = 
true with proto2.

I hope msg with proto2 still work with proto3 jar since proto2 has been 
widely used in opensource system like yarn, hbase, etc.



在 2015年9月7日星期一 UTC+8下午2:31:04，Feng Xiao写道：
>
> On Sat, Sep 5, 2015 at 9:08 PM, sam sun  
> wrote:
>
>> I use proto3 to log user event and then run a mapreduce to stat same 
>> metrics. But it reports an error:
>>
>> Exception in thread "Thread-2" java.lang.NoSuchMethodError: 
>> org.apache.hadoop.yarn.proto.YarnProtos$LocalResourceProto.hashLong(J)I
>> at 
>> org.apache.hadoop.yarn.proto.YarnProtos$LocalResourceProto.hashCode(YarnProtos.java:11555)
>> at 
>> org.apache.hadoop.yarn.api.records.impl.pb.LocalResourcePBImpl.hashCode(LocalResourcePBImpl.java:62)
>> at java.util.HashMap.hash(HashMap.java:338)
>> at java.util.HashMap.put(HashMap.java:611)
>>
>> The problem is proto3 doesn't keep backward compatibility with proto2. 
>> hashLong is no longer exists in generated code with proto3. Now I faced a 
>> deed situation that neither proto2 nor proto3 can be loaded when i run a 
>>  mapreduce job.
>>
> It seems the problem is that your binary depends on both proto2 Java 
> runtime and also proto3 Java runtime. One of them will be shadowed by the 
> other and you will see such runtime errors. The suggestion is to stick with 
> one version through out your project (including all your project's 
> dependencies).
>  
>
>>
>>
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>>
>
>

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Re: [protobuf] proto3 backward compatibility problem

['Feng Xiao' via Protocol Buffers]

On Sat, Sep 5, 2015 at 9:08 PM, sam sun  wrote:

> I use proto3 to log user event and then run a mapreduce to stat same
> metrics. But it reports an error:
>
> Exception in thread "Thread-2" java.lang.NoSuchMethodError:
> org.apache.hadoop.yarn.proto.YarnProtos$LocalResourceProto.hashLong(J)I
> at
> org.apache.hadoop.yarn.proto.YarnProtos$LocalResourceProto.hashCode(YarnProtos.java:11555)
> at
> org.apache.hadoop.yarn.api.records.impl.pb.LocalResourcePBImpl.hashCode(LocalResourcePBImpl.java:62)
> at java.util.HashMap.hash(HashMap.java:338)
> at java.util.HashMap.put(HashMap.java:611)
>
> The problem is proto3 doesn't keep backward compatibility with proto2.
> hashLong is no longer exists in generated code with proto3. Now I faced a
> deed situation that neither proto2 nor proto3 can be loaded when i run a
>  mapreduce job.
>
It seems the problem is that your binary depends on both proto2 Java
runtime and also proto3 Java runtime. One of them will be shadowed by the
other and you will see such runtime errors. The suggestion is to stick with
one version through out your project (including all your project's
dependencies).


>
>
> --
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> To post to this group, send email to protobuf@googlegroups.com.
> Visit this group at http://groups.google.com/group/protobuf.
> For more options, visit https://groups.google.com/d/optout.
>

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