There is a compatibility problem of DubboHeadersGetter#keys in Dubbo 2.7.6 and 2.7.7

[steverao]

Describe the bug

In Dubbo instrumentation, I found a compatibility problem of DubboHeadersGetter#keys in Dubbo 2.7.6, 2.7.7.
In related versions, the getAttachments is as follows:

@Deprecated
@Override
public Map<String, String> getAttachments() {
    return new AttachmentsAdapter.ObjectToStringMap(attachments);
}

public static class ObjectToStringMap extends HashMap<String, String> {
        private Map<String, Object> attachments;

        public ObjectToStringMap(Map<String, Object> attachments) {
            this.attachments = attachments;
        }

        @Override
        public String get(Object key) {
            Object obj = attachments.get(key);
            return convert(obj);
        }

        @Override
        public String put(String key, String value) {
            Object obj = attachments.put(key, value);
            return convert(obj);
        }

        @Override
        public String remove(Object key) {
            Object obj = attachments.remove(key);
            return convert(obj);
        }

        private String convert(Object obj) {
            if (obj instanceof String) {
                return (String) obj;
            }
            return null; // or JSON.toString(obj);
        }
    }

The ObjectToStringMap can't get all keySet by keySet method, so it can't get correct result of DubboHeadersGetter#keys in related version.

Steps to reproduce

We can compare the codes between Dubbo 2.7.6, 2.7.7 and others, we can get above conclusion by codes.

Expected behavior

DubboHeadersGetter#keys can't get correct result in Dubbo 2.7.6, 2.7.7

Actual behavior

DubboHeadersGetter#keys can get correct result in Dubbo 2.7.6, 2.7.7

Javaagent or library instrumentation version

2.11.0

Environment

No response

Additional context

No response

[laurit]

The ObjectToStringMap doesn't contain keySet method, so it can't get correct result of DubboHeadersGetter#keys in related version.

I don't get this. ObjectToStringMap extends HashMap that has keySet method. Elements added by super.put that is called in the constructor of ObjectToStringMap should be in that set. The implementation for ObjectToStringMap is different for versions 2.7.6 and 2.7.7 where super.put is not called in the constructor for ObjectToStringMap.

[steverao]

I don't get this. ObjectToStringMap extends HashMap that has keySet method. Elements added by super.put that is called in the constructor of ObjectToStringMap should be in that set. The implementation for ObjectToStringMap is different for versions 2.7.6 and 2.7.7 where super.put is not called in the constructor for ObjectToStringMap.

Yes, as your said, there are something wrong in previous description, I have corrected them.

[laurit]

Yes, as your said, there are something wrong in previous description, I have corrected them.

I think the title of the issue could also be changed to indicate that the issue is present only in a specific versions. Currently it leaves an impression that there is a problem in all versions later and including 2.7.6.

[steverao]

I think the title of the issue could also be changed to indicate that the issue is present only in a specific versions. Currently it leaves an impression that there is a problem in all versions later and including 2.7.6.

Sure, done