consensus-specs Remove SSZ unions

SSZ unions are not used and have never been used in any version of deployed consensus-layer Ethereum. Align spec with this.

Aug 29 '24 13:08 tersec

unions were used in very old versions of sharding specs, and its possible we could use them in future iterations of the spec

instead of deleting them, we could add a note that they are not part of a "core" or "minimum required functionality" SSZ implementation

Aug 29 '24 19:08 ralexstokes

another data point:

Portal uses unions in their networking specs here: https://github.com/ethereum/portal-network-specs/blob/master/portal-wire-protocol.md

Sep 05 '24 20:09 ralexstokes

I am closing this issue because it seems stale. Please, do not hesitate to reopen it if this is a mistake

Jun 04 '25 08:06 leolara

Yeah, I've been monitoring the relevant conditions for this.

The last real user was Portal, which is why I didn't take further action on it. But conditions around Portal changed.I

I'm not sure I can reopen, but it should be reopened.

Jun 04 '25 10:06 tersec

Has this been discussed in an EIP? If we want to modify the SSZ standard, I guess the community should give feedback through the EIP process?

Jun 10 '25 12:06 leolara