Dubbo throws exception when use java serializer

[qixiaobo]

The same problem like 2.6.x.
issues:
#3951
#3698

related-pr:
#2656

Since we have no reason make the method first line before decode!

We can see code from @liangfei0201 below

 // decode request.
            Request req = new Request(id);
            req.setVersion("2.0.0");
            req.setTwoWay((flag & FLAG_TWOWAY) != 0);
            if ((flag & FLAG_EVENT) != 0) {
                req.setEvent(Request.HEARTBEAT_EVENT);
            }
            try {
                Object data;
                if (req.isHeartbeat()) {
                    data = decodeHeartbeatData(channel, deserialize(s, channel.getUrl(), is));
                } else if (req.isEvent()) {
                    data = decodeEventData(channel, deserialize(s, channel.getUrl(), is));
                } else {
                    DecodeableRpcInvocation inv;
                    if (channel.getUrl().getParameter(
                        Constants.DECODE_IN_IO_THREAD_KEY,
                        Constants.DEFAULT_DECODE_IN_IO_THREAD)) {
                        inv = new DecodeableRpcInvocation(channel, req, is, proto);
                        inv.decode();
                    } else {
                        inv = new DecodeableRpcInvocation(channel, req,
                                                          new UnsafeByteArrayInputStream(readMessageData(is)), proto);
                    }
                    data = inv;
                }
                req.setData(data);
            } catch (Throwable t) {
                if (log.isWarnEnabled()) {
                    log.warn("Decode request failed: " + t.getMessage(), t);
                }
                // bad request
                req.setBroken(true);
                req.setData(t);
            }
            return req;

This code works well for java serializer.
We can see no call for method deserialize before DecodeableRpcInvocation.
#4530

[codecov-io]

Codecov Report

Merging #4613 into master will increase coverage by <.01%.
The diff coverage is 50%.

@@             Coverage Diff              @@
##             master    #4613      +/-   ##
============================================
+ Coverage     64.16%   64.17%   +<.01%     
  Complexity      452      452              
============================================
  Files           768      768              
  Lines         32873    32875       +2     
  Branches       5181     5181              
============================================
+ Hits          21093    21097       +4     
+ Misses         9363     9361       -2     
  Partials       2417     2417

Impacted Files	Coverage Δ	Complexity Δ
...rg/apache/dubbo/rpc/protocol/dubbo/DubboCodec.java	57.28% <50%> (-1.14%)	0 <0> (ø)
.../apache/dubbo/qos/protocol/QosProtocolWrapper.java	69.23% <0%> (-12.83%)	0% <0%> (ø)
...onfig/spring/extension/SpringExtensionFactory.java	80.48% <0%> (-4.88%)	0% <0%> (ø)
...he/dubbo/registry/multicast/MulticastRegistry.java	67.87% <0%> (-1.81%)	0% <0%> (ø)
.../dubbo/remoting/transport/netty4/NettyChannel.java	64.7% <0%> (-1.18%)	0% <0%> (ø)
...g/apache/dubbo/registry/consul/ConsulRegistry.java	61.87% <0%> (-0.63%)	29% <0%> (ø)
...exchange/support/header/HeaderExchangeHandler.java	67.21% <0%> (+2.45%)	0% <0%> (ø)	⬇️
.../apache/dubbo/remoting/transport/AbstractPeer.java	67.39% <0%> (+4.34%)	0% <0%> (ø)	⬇️
.../org/apache/dubbo/remoting/ExecutionException.java	21.05% <0%> (+5.26%)	0% <0%> (ø)	⬇️
...ng/transport/dispatcher/all/AllChannelHandler.java	57.14% <0%> (+5.71%)	0% <0%> (ø)	⬇️
... and 2 more

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[beiwei30]

LGTM.

[beiwei30]

@qixiaobo would you mind to double check if the same issue still exists on 2.6.x branch?

[qixiaobo]

@qixiaobo would you mind to double check if the same issue still exists on 2.6.x branch?
Yeah,I will check. I make pull request here #4530.
We use dubbo 2.6.x most.

[beiwei30]

ok, it's been merged already.