RpcContext's ServerContext can not transform data from provider to consumer when using sync invoke mode

[tswstarplanet]

• I have searched the issues of this repository and believe that this is not a duplicate.
• I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

• Dubbo version: 2.7.x
• Operating System version: MacOS
• Java version: 1.8

Steps to reproduce this issue

1. Execute following code in a method of a dubbo service on provider side:

RpcContext.getServerContext().setAttachment("abc", "123");

2. Execute following code in the same thread that invoke the remote dubbo service after the invoking:

Map<String, String> map = RpcContext.getServerContext().getAttachments();
System.out.println("context: " + map.get("abc"));

Pls. provide [GitHub address] to reproduce this issue.

Expected Result

Console output:
context: 123

Actual Result

context: null

What actually happens?

If there is an exception, please attach the exception trace:

Just put your stack trace here!

[tswstarplanet]

#3664

[carryxyh]

I think your pr will cause new problems.
@chickenlj Would you like to check this pr twice?

By the way, why create a new issue. Focus on #3620?

[tswstarplanet]

Because this pr cannot solve the problem when using async invoke

[carryxyh]

But it will cause another problem.
Pls check my comment under your pr.

[tswstarplanet]

I am not sure if the remove operation of servercontext that is execute in the onResponse method is equal to be executed in the invoke method.

[carryxyh]

of course not....
The two are not equal..

Since this pr can't fix the problem, I think we can close this issue and focus on #3620. What do u think

[tswstarplanet]

I think it is two problems, one is sync invoke, the other is async. We can remains them both, or merge to one

[carryxyh]

Maybe merge to one is better. We can change the title of #3620 to indicate there are some problems on server context.

[tswstarplanet]

OK

[carryxyh]

hi, @tswstarplanet
I'd like close this issue and pr.
Maybe we need more discuss with it.

[tswstarplanet]

I think the pr can be remained. It need some time to test ifit can solve the problem when using sync invoke without impacting async invoke. We donnot need to close one pr so quickly

[cvictory]

http://dubbo.apache.org/zh-cn/docs/user/demos/attachment.html

I remember the attachment value is transfered from consumer to provider but not provider to consumer.

[chickenlj]

I tried both sync and async invoke on 2.7.5, failed to reproduce, I think this issue does not exist or it's been fixed.