AbstractClientConnector violates basic Java contract of equals and hashcode and therefore should be replaced

[tangomannX]

Vaadin Framework version: 8.x

In AbstractClientConnector.equals you define your own implementation of how vaadin handles equality of UI classes in order to handle proxies (see #5655). Since you are using this implementation in several other classes internally in vaadin core one should not be able to override this with different behaviour. So equals method of AbstractClientConnector should either be final or another internal method should be used for proxy handling.

A follow up problem of this design glitch is that any class inheriting from vaadin component will cause a sonar violation (java:S2160) unless you provide your own equals method. In order to not break the vaadin ccore code by accident this implementation could only be: return super.equals(); This will for sure cause antoher sonar violation...

[tangomannX]

Two other problems I see here:

1. hashcode() method has no proxy handling, and therefore violating the api contract of hashcode
2. equals implementaion is violating the api contract since is is not symetric:
   myComponent.equals(myComponentProxied) => true
   myComponentProxied.equals(myComponent) => false

[stale]

Hello there!

We are sorry that this issue hasn't progressed lately. We are prioritizing issues by severity and the number of customers we expect are experiencing this and haven't gotten around to fix this issue yet.

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